diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-document-info.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-document-info.mdx new file mode 100644 index 000000000..f907f8c5c --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-document-info.mdx @@ -0,0 +1,25 @@ +--- +title: Document Info +reportDate: October 2026 +reportType: Technical Reference +reportTitle: Concentrated Leak Erosion Core Compaction Screening Technical Reference Manual +reportSubTitle: System Response Library +reportAuthors: ['Adam Gohs, P.E.'] +reportAbstract: Technical reference documenting the concentrated leak erosion (CLE) core compaction screening model in the System Response library. The model computes a system response probability (SRP) at each headwater level for concentrated leak erosion through a continuous zone of poorly compacted soil within the embankment core. The probability of the flaw is estimated by risk-factor and likelihood-factor scoring of the core compaction category, the width and width-to-height ratio of the embankment section, and borrow variability, followed by a flaw-continuity stage keyed to the compaction category; an observation of embankment leakage or wet spots overrides the flaw probability to certainty and sets the flaw elevation. Initiation is evaluated by a Monte Carlo cylindrical-pipe hydraulic shear stress analysis at the base of the flaw, and the remaining nodes of the eight-node CLE event tree follow the methods shared by the CLE screening family. The model applies simplifications appropriate for screening-level risk analysis. +reportSubjectTerms: ['CLE', 'Concentrated Leak Erosion', 'Core Compaction', 'Poor Compaction', 'Screening', 'Event Tree', 'System Response Probability', 'System Response Curve', 'Risk Factor', 'Likelihood Factor', 'Cylindrical Pipe', 'Critical Shear Stress', 'Monte Carlo'] +citationGuide: 'U.S. Army Corps of Engineers, Risk Management Center, Concentrated Leak Erosion Core Compaction Screening Technical Reference Manual, Lakewood, CO: U.S. Army Corps of Engineers, Risk Management Center, 2026.' +--- + +import Link from '@docusaurus/Link'; +import DocumentMetadata from '@site/src/components/DocumentMetadata'; +import NavContainer from '@site/src/components/NavContainer'; + + + +# Document Information + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-version-history.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-version-history.mdx new file mode 100644 index 000000000..27589fe61 --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/00-version-history.mdx @@ -0,0 +1,23 @@ +--- +title: Version History +--- + +import NavContainer from '@site/src/components/NavContainer'; +import TableVersionHistory from '@site/src/components/TableVersionHistory'; + + + +# Version History + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/01-preface.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/01-preface.mdx new file mode 100644 index 000000000..594c550ea --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/01-preface.mdx @@ -0,0 +1,42 @@ +--- +title: Preface +--- + +import NavContainer from '@site/src/components/NavContainer'; + + + +# Preface + +This document provides a technical reference for the concentrated leak erosion (CLE) core compaction screening model in the System Response +library. The model computes a system response probability (SRP) as a function of headwater elevation for concentrated leak erosion through a +continuous zone of poorly compacted soil within the embankment core. It is a screening-level model: it applies simplifications intended to reduce +input burden while avoiding false negatives, and any application that performs screening-level risk analysis can use it. + +The model is one of eight CLE screening models that share one event tree and most of their methods. Those shared methods are documented once, in +the [Concentrated Leak Erosion Common Methods Screening Technical Reference Manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/preface), +and the continuation node is evaluated by the shared method documented in the +[Continuation (Filter Evaluation) Screening Technical Reference Manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/preface). +This document covers what is specific to the core compaction mechanism: its flaw assessment, its mechanism-specific inputs, how it populates each +node of the shared event tree, the assumptions it adds, and the results it reports. Each section that relies on a shared method links the chapter +that documents it. + +The intended audience includes dam safety engineers evaluating whether the model is appropriate for their assessment, and peer reviewers checking +the technical basis of screening-level results. Readers are assumed to have a general background in internal-erosion risk analysis — event trees, +concentrated leak erosion mechanics, and probability concepts — but no familiarity with the software implementation is required. + +## Document Organization + +- **[Model Overview](./02-model-overview.mdx)** — The model's purpose and intended use, a summary of its execution pathway from inputs to + results, its engineering basis, a comparison with detailed methods, and how it relates to the shared CLE methods and the toolbox methods. +- **[Input Parameters](./03-input-parameters.mdx)** — The mechanism-specific inputs (the normal pool elevation, the core compaction category, the + leakage observation and its elevation, and the optional flaw base width and height), and how the model takes each of the inputs it shares with + the CLE family. +- **[Flaw Assessment](./04-flaw-assessment.mdx)** — The three scored factors, the weighted sum and its flaw-probability curve, the flaw-continuity + stage, the resulting flaw probabilities, the observation override, and the base-of-flaw elevation. +- **[Event Tree](./05-event-tree.mdx)** — How the model populates each of the eight nodes, including the cylindrical-pipe initiation analysis and + the continuation method it delegates to, and how the SRP is computed. +- **[Assumptions and Limitations](./06-assumptions-and-limitations.mdx)** — Each assumption the model adds to the shared CLE assumptions, with its + engineering basis, its effect on results, and the conditions under which it may not hold. +- **[Output and Interpretation](./07-output-and-interpretation.mdx)** — The results the model produces, how to read the flaw assessment and the + system response curve, checks on a result, and the role of screening results relative to detailed analysis. diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/02-model-overview.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/02-model-overview.mdx new file mode 100644 index 000000000..4d4039bda --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/02-model-overview.mdx @@ -0,0 +1,140 @@ +--- +title: Model Overview +--- + +import Citation from '@site/src/components/Citation'; +import CitationFootnote from '@site/src/components/CitationFootnote'; +import NavContainer from '@site/src/components/NavContainer'; +import TableReference from '@site/src/components/TableReference'; +import TableVertical from '@site/src/components/TableVertical'; + + + +# Model Overview + +## Purpose + +The CLE core compaction screening model computes a system response curve for concentrated leak erosion through a continuous zone of poorly +compacted soil within the embankment core, as a function of headwater elevation. The system response probability (SRP) at each headwater level is +the conditional probability of breach of the embankment by concentrated leak erosion along such a zone, given that pool level. + +The flaw is a zone of poorly compacted soil that runs continuously through the core from the upstream face to the downstream face, so that water +from the reservoir can flow along it. The model idealizes the zone as a horizontal cylindrical pipe at a base-of-flaw elevation. Erosion begins when +the hydraulic shear stress of the flow on the pipe wall exceeds the critical shear stress of the core soil, and breach requires the further +conditions common to every concentrated leak erosion failure mode: an unfiltered exit, a pipe that stays open and is neither filled nor starved of +flow, unsuccessful intervention, and an uncontrolled release of the impounded water (see the +[Model Overview](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#purpose) of the CLE Common Methods +manual). + +## Intended Use + +The model is a screening-level assessment of concentrated leak erosion through poorly compacted core material. Like the other CLE screening models, +it makes simplifying and generally conservative assumptions with two goals +(see [Intended Use](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#intended-use) in the CLE Common +Methods manual): + +- **Preventing false negatives** — The model is designed to avoid underestimating risk at the screening level, so that embankments with a + potential core compaction concern are flagged for further analysis. +- **Reducing input burden** — A qualitative core compaction category and the dimensions of the embankment section stand in for a detailed review of + construction records, and default distributions cover the critical shear stress of the core soil and the initial diameter of the flaw. Where the + compaction of the core is not known, the user selects Unknown rather than guessing. + +The model is not intended for detailed or semi-quantitative risk assessments. For those, the concentrated leak erosion toolbox methods and the +internal-erosion probability methods of Fell et al. (2024) provide the complete methodologies (see +[Comparison with Detailed Models](#comparison-with-detailed-models)). + +## How the Model Works + +The model executes three stages: + +1. **Flaw assessment** — The model scores three factors: the core compaction category, the continuity of the embankment section (its base width and + its width-to-height ratio), and borrow variability, which is fixed. The weighted sum of the scores is converted to a raw flaw probability, which + is multiplied by a flaw-continuity probability keyed to the compaction category. The base of the flaw is placed one third of the way from the + normal pool to the crest. An observation of embankment leakage or wet spots replaces both results: the flaw probability becomes 1.0 and the base + of the flaw becomes the observed elevation. The flaw probability is the same at every pool level (see [Flaw Assessment](./04-flaw-assessment.mdx)). + +2. **Pathway resolution** — The flaw is at one elevation, so the failure pathway is fixed: the user states whether a filter intercepts it by + supplying, or omitting, the filter and base-soil description, and lists the embankment materials the pipe passes through and the upstream + seepage-limiting elements present. A wall whose top is below the base of the flaw is set aside (see [Event Tree](./05-event-tree.mdx)). + +3. **Event-tree assembly** — At each headwater level, the model multiplies the probabilities of the eight CLE event-tree nodes to produce the SRP. + Initiation is evaluated by a Monte Carlo cylindrical-pipe analysis of the hydraulic shear stress at the base of the flaw and is the only node that + varies with pool level; the other seven nodes are each one value (see [Event Tree](./05-event-tree.mdx)). + +## Physics Basis + +The model combines the following engineering methods: + +- **Risk-factor and likelihood-factor scoring** for the probability that a continuous poorly compacted zone exists, in which each factor is + assigned a likelihood factor, weighted by a risk factor, and the weighted sum is mapped to a flaw probability + (see the [Risk-Factor and Likelihood-Factor Scoring](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#risk-factor-and-likelihood-factor-scoring) + section of the CLE Common Methods manual) +- **Hydraulic shear stress on the wall of a cylindrical pipe**, compared with the critical shear stress of the core soil, for the initiation of + erosion, as documented in the + [Cylindrical Pipe](/docs/toolbox-technical-manuals/internal-erosion-suite/concentrated-leak-erosion-initiation/v1.0/cylindrical-pipe) chapter + of the Concentrated Leak Erosion Initiation manual +- **Filter evaluation** for the probability that erosion continues past a filter intercepting the pathway, through the shared continuation method + documented in the + [Method Selection and Governing Base Soil](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/method-selection-and-governing-base-soil) + chapter and the method chapters of the Continuation (Filter Evaluation) Screening manual +- **Roof-support, crack-filling, and flow-limitation probabilities** for the progression conditions , as + documented in the + [Failure Pathway and Progression](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression) + chapter of the CLE Common Methods manual + +## Comparison with Detailed Models + +The detailed counterparts of the screening model are the concentrated leak erosion toolbox methods and the internal-erosion probability methods of +Fell et al. (2024) applied in full. The comparison that holds for the whole CLE family is given in +[Comparison with Detailed Models](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#comparison-with-detailed-models) +in the CLE Common Methods manual. summarizes the differences specific to a core +compaction flaw. + + + +## Relationship to the Common Methods and Toolbox Models + +The core compaction model is one of the four compaction models of the CLE family (see +[The Two Model Groups](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/model-overview#the-two-model-groups) in the CLE +Common Methods manual). It shares the following with the family, and this manual links the shared documentation rather than repeating it: + +- **The eight-node event tree and the SRP computation** — the + [Event Tree](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree) chapter of the CLE Common Methods manual. +- **The scoring scheme, the flaw-continuity stage, and the normal-pool heuristic for the base of the flaw** — the + [Flaw Conventions](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions) chapter. +- **The cylindrical-pipe initiation analysis**, which the model hands to the same method as the standalone Concentrated Leak Erosion Initiation + toolbox, supplying the base of the flaw, the embankment section, and default distributions for the critical shear stress and the initial pipe + diameter — the + [Delegated Method: Cylindrical Pipe Initiation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#delegated-method-cylindrical-pipe-initiation) + section of the Initiation chapter. +- **The continuation, roof-support, crack-filling, and flow-limitation nodes** — the + [Failure Pathway and Progression](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression) + chapter, with the continuation method itself in the Continuation (Filter Evaluation) Screening manual. + +What this manual documents in full is the flaw assessment ([Flaw Assessment](./04-flaw-assessment.mdx)), the mechanism-specific inputs +([Input Parameters](./03-input-parameters.mdx)), and the choices this model makes where the family allows more than one +([Event Tree](./05-event-tree.mdx)). + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/03-input-parameters.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/03-input-parameters.mdx new file mode 100644 index 000000000..5fdcda1ed --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/03-input-parameters.mdx @@ -0,0 +1,157 @@ +--- +title: Input Parameters +--- + +import NavContainer from '@site/src/components/NavContainer'; +import TableReference from '@site/src/components/TableReference'; +import TableVertical from '@site/src/components/TableVertical'; + + + +# Input Parameters + +The core compaction model takes two kinds of input. Most are the inputs shared by the CLE family, documented in full in the +[Common Input Parameters](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters) chapter of the CLE Common +Methods manual: the hydraulic loading, the units and datum convention, the embankment description, the failure-pathway inputs, the upstream +seepage-limiting elements, the initiation material inputs of the compaction models, and the intervention and breach probabilities. The rest are +specific to this mechanism: the normal pool elevation, the flaw inputs, and two optional dimensions that replace the section geometry in the flaw +scoring. This chapter documents the mechanism-specific inputs in full, then states how the model takes each shared input where the family allows +more than one form. + +## Mechanism-Specific Inputs + + lists the mechanism-specific inputs. All elevations are on the datum of the +headwater series and all lengths are in its unit (see +[Units and Datum](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#units-and-datum) in the CLE Common +Methods manual). + +np', '—', '—', 'zlk', 'W', 'H'], + ['elevation', 'selection', 'yes or no', 'elevation', 'length', 'length'], + [ + 'Finite; below the crest', + 'One of four categories', + 'Yes or no', + 'Finite; within the embankment section', + '> 0', + '> 0', + ], + [ + 'Required', + 'Required unless leakage is observed', + 'No', + 'Required when leakage is observed', + 'Derived from the section', + 'Derived from the section', + ], + ]} +/> + +### Normal pool elevation + +The normal pool elevation $z_{np}$ is the lower reference of the heuristic that places the base of the flaw one third of the way from the normal +pool to the crest (see [Flaw Assessment](./04-flaw-assessment.mdx#base-of-the-flaw)). It is supplied by the user and is not taken from the headwater +series. The crest elevation $z_c$ must be above it. The normal pool is required even when an observation of leakage sets the base of the flaw, +although it then has no effect on the result. + +### Core compaction category + +The core compaction category describes the compaction of the core material and is the most heavily weighted factor of the flaw assessment (see +[Flaw Assessment](./04-flaw-assessment.mdx#compaction-factor)). The choices are: + +- **Well compacted** — the least likely condition for a continuous poorly compacted zone. +- **Poorly compacted** +- **Very poorly compacted** — the most likely condition for a continuous poorly compacted zone. +- **Unknown** — the compaction of the core cannot be judged from the available information. + +The category is required unless an observation of leakage or wet spots is reported. When the observation is reported, the category is optional; if +it is supplied, the model still scores it and reports the scores, but the scores do not affect the result. + +:::warning[INPUT NEEDED IN-01 — Definition] +The four core compaction categories (Well compacted, Poorly compacted, Very poorly compacted, Unknown) are offered without a definition. State what +construction practice or evidence each category represents — for example, the compaction equipment, lift thickness, moisture control, and density +testing that place a core in each category — so that the user can select between them, or cite the table in Fell et al. (2024) that defines them. +State also when Unknown should be selected rather than a judged category, given that Unknown scores between Poorly compacted and Very poorly +compacted (see [Flaw Assessment](./04-flaw-assessment.mdx#compaction-factor)). +::: + +### Embankment leakage or wet spots observed + +Reporting that leakage or wet spots have been observed on the embankment states that the flaw is demonstrated. The flaw probability is then 1.0, +whatever the compaction category and the section geometry would score, and the base of the flaw is set to the observed elevation (see +[Flaw Assessment](./04-flaw-assessment.mdx#observation-override)). When no observation is reported, the flaw probability is scored. + +### Leakage or wet-spot elevation + +The leakage or wet-spot elevation $z_{lk}$ is the elevation of the observed leakage or wet spots. It is required when an observation is reported +and becomes the base of the flaw, replacing the normal-pool heuristic. Like any base of the flaw, it must lie within the embankment section used for +initiation: at or below the top of that section, at or above the lowest segment bottom of each face, and at a positive elevation (see +[Flaw Assessment](./04-flaw-assessment.mdx#base-of-the-flaw)). What the elevation should represent is requested at marker IN-08 in +[Flaw Assessment](./04-flaw-assessment.mdx#observation-override). + +### Flaw base width and flaw height + +The continuity factor of the flaw assessment bands the base width $W$ of the embankment section and its width-to-height ratio $W/H$ (see +[Flaw Assessment](./04-flaw-assessment.mdx#continuity-factor)). By default both are derived from the embankment section the model uses — the core +section when one is supplied, the shell section otherwise — as described in +[Section Geometry Used in Scoring](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#section-geometry-used-in-scoring) +in the CLE Common Methods manual: $W$ is the top width of the section plus the horizontal spans of both faces down to its lowest segment bottom, and +$H$ is the height of the section from that bottom to its top. + +Either dimension may be supplied instead, and each must then be positive. A supplied value replaces the derived value in the flaw scoring only; the +initiation analysis always uses the embankment section itself. The section must still resolve to a positive height and base width. + +:::warning[INPUT NEEDED IN-02 — Definition] +State what the user-supplied flaw base width $W$ and flaw height $H$ are meant to represent and when they should be supplied in place of the +dimensions derived from the embankment section — for example, where the low-permeability part of the section is bounded by a drain or filter zone +that the slope-segment tables do not describe, or where the core section is not supplied. + +Proposed (unconfirmed): $W$ is the horizontal width of the section at its base, measured from the upstream toe to the first drain or filter zone the +pathway meets (or from toe to toe when there is none), and $H$ is the height from the crest to the lower of the two toes. Confirm or replace. +::: + +## How the Model Takes the Shared Inputs + +The shared inputs are documented in the CLE Common Methods manual. Where the family allows a choice, the core compaction model takes them as +follows. + +- **Hydraulic loading** — a headwater series and an optional tailwater series, as described in + [Hydraulic Loading](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#hydraulic-loading). Tailwater + reduces the net head across the flaw in the initiation analysis. +- **Embankment description** — the crest elevation $z_c$, the embankment type, the shell section, and the optional core section, as described in + [Embankment Description](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#embankment-description). + When a core section is supplied, it is used for both the flaw scoring and the initiation analysis, whatever the embankment type; + otherwise the shell section is used. A partially described core section leaves the inputs inconsistent, and the analysis is not evaluated; the shell is not substituted for it. The embankment type sets only the crack-filling probability. The crest elevation, not the top of the core, + is the upper reference of the base-of-flaw heuristic. +- **Filter presence and continuation inputs** — this model has no separate filter-presence selection. Supplying the filter and base-soil + description of the shared continuation method states that a filter intercepts the failure pathway at the base of the flaw; omitting it states + that none does (see + [Failure-Pathway Inputs](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#failure-pathway-inputs) and + the [Input Parameters](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/input-parameters) chapter of the Continuation (Filter + Evaluation) Screening manual). The model does not compare the filter with any elevation, so the user decides whether the filter reaches the base + of the flaw. +- **Embankment materials** — the USCS classes of the materials the pipe passes through, at least one, which set the roof-support probability. The + core soil classification is not added to this list automatically; the core material is listed here if the pipe passes through it. +- **Upstream seepage-limiting elements and top-of-wall elevation** — as described in + [Upstream Seepage-Limiting Elements](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#upstream-seepage-limiting-elements). + A top-of-wall elevation may be given only when a wall is among the elements, and is compared once with the base of the flaw. +- **Initiation material inputs** — the core soil classification and the optional critical shear stress, initial pipe diameter, and seepage path + length, as described in + [Initiation Material Inputs](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#initiation-material-inputs). + Left blank, the initial pipe diameter defaults to a triangular distribution with a low value of 2 mm, a most likely value of 3 mm, and a high + value of 5 mm (see [Event Tree](./05-event-tree.mdx#node-2-initiation)). +- **Intervention and breach** — the probabilities of unsuccessful intervention and of breach, each defaulting to 1.0, as described in + [Intervention and Breach](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/input-parameters#intervention-and-breach). diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/04-flaw-assessment.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/04-flaw-assessment.mdx new file mode 100644 index 000000000..f9e6f5838 --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/04-flaw-assessment.mdx @@ -0,0 +1,277 @@ +--- +title: Flaw Assessment +--- + +import Citation from '@site/src/components/Citation'; +import CitationFootnote from '@site/src/components/CitationFootnote'; +import Equation from '@site/src/components/Equation'; +import EquationReference from '@site/src/components/EquationReference'; +import NavContainer from '@site/src/components/NavContainer'; +import TableReference from '@site/src/components/TableReference'; +import TableVertical from '@site/src/components/TableVertical'; + + + +# Flaw Assessment + +Node 1 of the event tree is the probability $P_{flaw}$ that a continuous zone of poorly compacted soil exists through the embankment core. The flaw +assessment also fixes the base-of-flaw elevation $z_f$, which sets the pipe invert of the initiation analysis (Node 2) and is the elevation the +top of any upstream wall is compared with (Node 6); the other nodes do not use it. The assessment is deterministic and does not depend on pool level, so $P_{flaw}$ and $z_f$ are the same at every headwater. + +The assessment follows the conventions shared by the CLE family, documented in the +[Flaw Conventions](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions) chapter of the CLE Common Methods +manual. It runs in two stages: + +1. **Scoring** — three factors are scored and combined into a weighted sum, which is converted to a raw flaw probability $P_{raw}$. +2. **Flaw continuity** — $P_{raw}$ is multiplied by a flaw-continuity probability $P_{cf}$ keyed to the compaction score, giving $P_{flaw}$. + +An observation of embankment leakage or wet spots overrides both stages and the base-of-flaw heuristic (see +[Observation Override](#observation-override)). + +## Factors + +The model scores the three factors of by the risk-factor and likelihood-factor +scheme of Fell et al. (2024) , described in +[Risk-Factor and Likelihood-Factor Scoring](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#risk-factor-and-likelihood-factor-scoring) +in the CLE Common Methods manual. Each factor carries a risk factor $RF$, its weight, and a likelihood factor $LF$ on a scale on which 1 is the least +likely condition for a flaw and 4 the most likely. + + + +:::warning[INPUT NEEDED IN-03 — Engineering Basis] +The choice of the three factors and their risk factors (core compaction 3, continuity 2, borrow variability 1) requires an engineering basis. +Provide the table of Fell et al. (2024) from which the factors and weights are taken, or the engineering-judgment attribution to state here. +::: + +### Compaction factor + +The likelihood factor of the core compaction factor, $LF_{comp}$, is set by the core compaction category +(). The table also gives the flaw-continuity probability $P_{cf}$ that the same +score selects in the second stage (see [Flaw Continuity](#flaw-continuity)). + +-3', '1 × 10-1', '1 × 10-2'], + ]} +/> + +No category carries a likelihood factor of 2. The Unknown category scores 3.5, between Poorly compacted and Very poorly compacted, so selecting +Unknown gives a higher flaw probability than selecting Poorly compacted. + +:::warning[INPUT NEEDED IN-04 — Engineering Basis] +The compaction likelihood factors of (Well compacted 1, Poorly compacted 3, +Very poorly compacted 4, Unknown 3.5) require an engineering basis. State the source of the values, why no category scores 2, and why Unknown is +scored at 3.5 — above Poorly compacted — rather than at a central value. Provide the table of Fell et al. (2024) they are taken from, or the +engineering-judgment attribution. + +Proposed (unconfirmed): Unknown is scored toward the poorly compacted end of the scale as a conservative screening posture, so that a core whose +compaction cannot be judged is not credited as better compacted than the evidence supports. Confirm or replace. +::: + +### Continuity factor + +The continuity factor scores the dimensions of the embankment section through which a poorly compacted zone would have to run. Its likelihood +factor $LF_{cont}$ is the larger of two banded scores, one of the base width $W$ and one of the width-to-height ratio $W/H$: + + + + + +where $W$ and $H$ are the base width and height of the embankment section — the core section when one is supplied, otherwise the shell — or the +user-supplied flaw base width and flaw height (see [Input Parameters](./03-input-parameters.mdx#flaw-base-width-and-flaw-height)). The section +height $H$ is the quantity written $H_s$ in +[Section Geometry Used in Scoring](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#section-geometry-used-in-scoring) +in the CLE Common Methods manual. The base width is in the length unit of the elevations. lists the bands. + + + +Taking the larger of the two scores means that either a narrow section or a slender one is enough to make a continuous flaw more likely: a section +scores 1 only when it is both wider than 50 and more than twice as wide as it is high. A band boundary itself belongs to the band below it; for +example, a base width of exactly 50 scores 2. + +:::warning[INPUT NEEDED IN-05 — Engineering Basis] +The continuity bands of (base width boundaries 50, 30, and 15; width-to-height +boundaries 2, 0.75, and 0.25) and the rule that the larger of the two scores governs () +require an engineering basis. Provide the source table or the engineering-judgment attribution, and state the unit of the base-width boundaries: +the model applies them to the base width in whatever length unit the elevations use, with no conversion. + +Proposed (unconfirmed): the base-width boundaries are in feet, so a user working in meters should convert the section before running the model. +Confirm or replace. +::: + +### Borrow variability factor + +The borrow variability factor has a fixed likelihood factor $LF_{var} = 2.5$. It is not a user selection and does not vary between sites. + +:::warning[INPUT NEEDED IN-06 — Engineering Basis] +The borrow variability factor and its fixed likelihood factor of 2.5 require a definition and an engineering basis. State what the factor represents +physically (for example, the variability of the borrow material placed in the core, which can leave zones of more erodible or less compactable +soil), why it is fixed rather than selected by the user, and the basis for the value of 2.5, between likelihood factors 2 and 3. +::: + +## Weighted Sum and Raw Flaw Probability + +The three scores combine into the weighted sum + + + +with $LF_{var} = 2.5$, which ranges from 7.5 (well compacted, continuity score 1) to 22.5 (very poorly compacted, continuity score 4). The raw flaw probability $P_{raw}$ is +interpolated from , linearly in the logarithm of the probability between +tabulated points, as described in +[Flaw Probability from the Weighted Sum](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#flaw-probability-from-the-weighted-sum) +in the CLE Common Methods manual. + +-4', '5 × 10-4', '2 × 10-3', '4 × 10-2', '5 × 10-1'], + ]} +/> + +Every attainable weighted sum lies inside the tabulated range, so the end values are never held. Because the lowest point carries a negligible +probability, the raw probability falls steeply below a weighted sum of 9; at the lowest attainable sum of 7.5 it is several orders of magnitude +below 1 × 10-4. That range matters only for a well-compacted core, whose flaw probability is negligible after the flaw-continuity stage +in any case. The model applies no lower threshold and no incompatible-condition factor, so no score forces $P_{raw}$ to zero. + +:::warning[INPUT NEEDED IN-07 — Engineering Basis] +The tabulated raw flaw probabilities of (weighted sum 6, 9, 11, 13, 18, 24 → +negligible, 1 × 10-4, 5 × 10-4, 2 × 10-3, 4 × 10-2, 5 × 10-1) require an engineering +basis. Provide the figure or table of Fell et al. (2024) from which they are taken, or the engineering-judgment attribution, including the basis for +anchoring the curve at a negligible probability at a weighted sum of 6, below the lowest attainable sum of 7.5. +::: + +## Flaw Continuity + +The second stage multiplies the raw probability by the flaw-continuity probability $P_{cf}$, interpolated log-linearly from the compaction score +on the curve the model shares with the wall or cliff and the foundation or abutment compaction models (see +[Flaw-Continuity Stage](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#flaw-continuity-stage) in the CLE +Common Methods manual): + + + +The value for each category is listed in . The Unknown score of 3.5 is +interpolated between the points at 3 and 4, giving 1 × 10-2. The point of the curve at a score of 2 (1 × 10-4) is not used +by this model, because no category scores 2. + +The compaction category therefore enters the flaw probability twice: through its weight of 3 in the weighted sum, and again through $P_{cf}$. The +section geometry enters only through the weighted sum. + +## Resulting Flaw Probability + +Because borrow variability is fixed, the flaw probability depends only on the compaction category and the continuity score. + lists every combination. + +-6', '1.6 × 10-3', '6.6 × 10-5'], + ['Negligible', '8.9 × 10-6', '4.9 × 10-3', '2.2 × 10-4'], + ['Negligible', '3.0 × 10-5', '1.1 × 10-2', '6.1 × 10-4'], + ['Negligible', '7.5 × 10-5', '2.7 × 10-2', '1.4 × 10-3'], + ]} +/> + +A well-compacted core has a negligible flaw probability whatever the section geometry, because its flaw-continuity +probability is negligible. For the other categories, each step in the continuity score raises the flaw probability by a factor of about 2 to 3.5, +while moving from Poorly compacted to Very poorly compacted raises it by a factor of about 350 to 600, with Unknown in between. + +### Example + +An embankment section with a base width of 350 and a height of 60 (from its base at elevation 205 to a crest at elevation 265), a core of Unknown +compaction, and a normal pool at elevation 235 scores as follows: + +- $W = 350$ is greater than 50, so $LF_W = 1$; $W/H = 5.83$ is greater than 2, so $LF_{W/H} = 1$; hence $LF_{cont} = 1$. +- Unknown compaction gives $LF_{comp} = 3.5$. +- $\Sigma = 3 \times 3.5 + 2 \times 1 + 2.5 = 15$. +- Between the tabulated points at 13 and 18, $P_{raw} = 2 \times 10^{-3} \times (20)^{0.4} \approx 6.6 \times 10^{-3}$. +- $P_{cf}(3.5) = 1 \times 10^{-2}$, so $P_{flaw} \approx 6.6 \times 10^{-5}$. +- The base of the flaw is $z_f = 235 + (265 - 235)/3 = 245$. + +## Observation Override + +When embankment leakage or wet spots are reported as observed, the flaw is taken as demonstrated: + + + +where $z_{lk}$ is the observed leakage or wet-spot elevation. The override replaces the scored probability and the normal-pool heuristic together. +It is the only CLE compaction override that also moves the flaw elevation (see +[Observation Overrides](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#observation-overrides) in the CLE +Common Methods manual). If a compaction category is supplied with the observation, the factors are still scored and reported, but they do not +affect the result; without a category, no scores are reported. The override sets only Node 1 and the flaw elevation: every downstream node is +evaluated as usual at the observed elevation. + +:::warning[INPUT NEEDED IN-08 — Definition] +State which elevation the user should enter as the leakage or wet-spot elevation $z_{lk}$ — for example, the elevation of the observed seepage exit +on the downstream face, or the lowest observed wet spot when several are observed — and the basis for taking it as the invert of a horizontal pipe +through the core. The pipe is analyzed at this elevation from the upstream face to the downstream face, so an exit that the flaw reaches by a +sloping path would place the pipe at the exit elevation rather than at the elevation of the flaw within the core. +::: + +## Base of the Flaw + +Without an observation, the base of the flaw is placed by the normal-pool heuristic shared with the abutment case of the foundation or abutment +compaction model, one third of the way from the normal pool elevation $z_{np}$ to the crest elevation $z_c$: + + + +The heuristic is documented in +[Compaction Models: Base of the Flaw](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#compaction-models-base-of-the-flaw) +in the CLE Common Methods manual. The upper reference is always the crest of the embankment, even when a core section with a lower top is supplied. + +Whichever way it is resolved, the base of the flaw is the invert of the pipe in the initiation analysis and must lie within the embankment section +used for initiation: at or below the top of that section (the core top when a core section is supplied, otherwise the crest), at or above the lowest +segment bottom of each face, and at a positive elevation. An analysis whose base of the flaw falls outside these limits — for example, a core top +below the heuristic elevation — is not evaluated, because its inputs are inconsistent. + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/05-event-tree.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/05-event-tree.mdx new file mode 100644 index 000000000..e15699192 --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/05-event-tree.mdx @@ -0,0 +1,179 @@ +--- +title: Event Tree +--- + +import Equation from '@site/src/components/Equation'; +import NavContainer from '@site/src/components/NavContainer'; +import TableReference from '@site/src/components/TableReference'; +import TableVertical from '@site/src/components/TableVertical'; + + + +# Event Tree + +The core compaction model computes the SRP at each headwater level from the eight-node event tree shared by the CLE family. The structure of the +tree, how it relates to the concentrated leak erosion trees of the Typical Event Tree Database, the headwater grid on which it is evaluated, and the +general form of each node are documented in the +[Event Tree](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree) chapter of the CLE Common Methods manual. This +chapter states how the core compaction model populates each node. + +## Node Summary + + summarizes the nodes. Only initiation varies with pool level: the flaw is at +one elevation, so the filter it meets, the materials it passes through, and the walls that reach it are the same at every pool level (see +[Pool Dependence](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree#pool-dependence) in the CLE Common Methods +manual). + + + +## Node 1: Flaw + +*Question:* Does a continuous zone of poorly compacted soil exist through the embankment core? + +$P_{flaw}$ and the base-of-flaw elevation $z_f$ come from the flaw assessment documented in [Flaw Assessment](./04-flaw-assessment.mdx). + +## Node 2: Initiation + +*Question:* At each pool level, does the flow through a pipe of initial diameter $D$ at the base of the flaw exert a hydraulic shear +stress on the pipe wall that exceeds the critical shear stress $\tau_c$ of the core soil? + +The model hands this question to the cylindrical-pipe initiation analysis, documented for the compaction models in +[Delegated Method: Cylindrical Pipe Initiation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#delegated-method-cylindrical-pipe-initiation) +in the CLE Common Methods manual, with its theory in the +[Cylindrical Pipe](/docs/toolbox-technical-manuals/internal-erosion-suite/concentrated-leak-erosion-initiation/v1.0/cylindrical-pipe) chapter of the +Concentrated Leak Erosion Initiation manual. The analysis compares the two stresses over Monte Carlo realizations of $\tau_c$ and $D$, and the +initiation probability $P_{init}(h)$ at each pool level is the fraction of realizations in which the hydraulic shear stress exceeds $\tau_c$. + +The core compaction model supplies the analysis with: + +- **The pipe invert** — the base of the flaw $z_f$ from the flaw assessment: the normal-pool heuristic, or the observed leakage elevation. +- **The embankment section** — the core section when one is supplied, otherwise the shell section, from which the seepage path length is measured + as a horizontal line at the invert (see + [Seepage Path Length](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#seepage-path-length) in the CLE Common + Methods manual), unless the user supplies a seepage path length. +- **The critical shear stress** — a triangular distribution over the range for the core soil classification (see + [Critical Shear Stress](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#critical-shear-stress) in the CLE + Common Methods manual), unless the user supplies a distribution. +- **The initial pipe diameter** — a triangular distribution with a low value of 2 mm, a most likely value of 3 mm, and a high value of 5 mm, the + range the model shares with the foundation or abutment compaction model (see + [Initial Pipe Diameter](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#initial-pipe-diameter) in the CLE + Common Methods manual), unless the user supplies a distribution. +- **The headwater and tailwater series** — evaluated on the headwater grid described in + [Headwater Grid](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree#headwater-grid) in the CLE Common Methods + manual. + +The model makes no adjustment to the analysis beyond the screening-level choices common to the compaction models (see +[Screening-Level Adjustments](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#screening-level-adjustments) in +the CLE Common Methods manual). Because the pipe invert is at the base of the flaw, initiation is zero at every pool level at or below $z_f$. + +## Node 3: Continuation + +*Question:* Does a filter intercepting the failure pathway at the base of the flaw fail to stop the erosion, so that the eroded soil +leaves the embankment through an unfiltered exit? + +Where a filter intercepts the pathway, the model hands this question to the shared continuation method, which selects a method for each base soil +from the information supplied and takes the governing result, as documented in +[Method Selection and Governing Base Soil](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/method-selection-and-governing-base-soil) +in the Continuation (Filter Evaluation) Screening manual. The model's use of it is documented in +[Node 3: Continuation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#node-3-continuation) +in the CLE Common Methods manual. The core compaction model applies it as follows: + + + +where $P_{ce}$ is the probability of continuing erosion from the continuation method. Supplying the filter and base-soil description is how the +user states that a filter intercepts the pathway; the model has no separate filter-presence selection and does not compare the filter with the +base of the flaw or with any other elevation. Because the base of the flaw is fixed, $P_{cont}$ is one value at every pool level. The +continuation method is not evaluated when no filter inputs are supplied. + +The user resolves the filter question at the base of the flaw $z_f$, whichever way it is set. A filter whose top lies below $z_f$ — the +heuristic elevation or the observed leakage elevation $z_{lk}$ — does not intercept the pathway at the flaw elevation and should not be supplied. +For example, when the base of the flaw comes from the normal-pool heuristic, its elevation is $z_{np} + (z_c - z_{np})/3$ (see +[Flaw Assessment](./04-flaw-assessment.mdx#base-of-the-flaw)), and only a filter whose top reaches that elevation should be supplied. + +## Node 4: Progression — Roof Support + +*Question:* Does a continuous stable roof form over the enlarging pipe, so that it stays open? + +$P_{roof}$ is the minimum of the roof-support probabilities of the embankment materials the user lists, from the table in +[Node 4: Progression — Roof Support](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#node-4-progression--roof-support) +in the CLE Common Methods manual. At least one material must be listed. The same value applies at every pool level. + +## Node 5: Progression — No Crack Filling + +*Question:* Does the enlarging pipe remain unfilled by material carried in from upstream? + +$P_{nf}$ is set by the embankment type, from the table in +[Node 5: Progression — No Crack Filling](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#node-5-progression--no-crack-filling) +in the CLE Common Methods manual. The embankment type has no other effect in this model. + +## Node 6: Progression — No Flow Limitation + +*Question:* Does the flow into the enlarging pipe remain unrestricted by upstream seepage-limiting elements? + +$P_{nl}$ is the minimum of the probabilities of no flow limitation of the upstream elements that apply, or 1.0 when none is listed, from the table +in +[Node 6: Progression — No Flow Limitation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#node-6-progression--no-flow-limitation) +in the CLE Common Methods manual. When a top-of-wall elevation $z_{tw}$ is supplied, the walls are judged once against the base of the flaw, as +described in +[Walls That Stop Below the Crest](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/failure-pathway-and-progression#walls-that-stop-below-the-crest): + +- $z_{tw} \ge z_f$ — the wall reaches the flaw, and every listed element applies. +- $z_{tw} < z_f$ — the walls drop out, and only the upstream facing element, if listed, applies. + +With no top-of-wall elevation, every listed element applies. Under an observation override, the comparison is made against the observed leakage +elevation, since that is then the base of the flaw. Either way, one value applies at every pool level. + +## Nodes 7 and 8: Unsuccessful Intervention and Breach + +*Questions:* Do detection and intervention fail (Node 7)? Does an uncontrolled release of impounded water occur (Node 8)? + +$P_{int}$ and $P_{br}$ are the user-specified values, each defaulting to 1.0, applied at every pool level (see +[Nodes 7 and 8](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree#nodes-7-and-8-unsuccessful-intervention-and-breach) +in the CLE Common Methods manual). + +## SRP Computation + +The SRP at each pool level $h$ is the product of the eight node probabilities, of which only initiation depends on $h$: + + + +A product smaller than a negligibly small value, including a product of zero, is reported as that value instead (see +[SRP Computation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/event-tree#srp-computation) in the CLE Common Methods +manual). The SRP takes this value at every pool level at or below the base of the flaw, where initiation is zero, and at every pool level when the +core is well compacted and no observation override applies, because its flaw probability is smaller still. diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/06-assumptions-and-limitations.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/06-assumptions-and-limitations.mdx new file mode 100644 index 000000000..ac6f14de8 --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/06-assumptions-and-limitations.mdx @@ -0,0 +1,114 @@ +--- +title: Assumptions and Limitations +--- + +import Citation from '@site/src/components/Citation'; +import CitationFootnote from '@site/src/components/CitationFootnote'; +import NavContainer from '@site/src/components/NavContainer'; + + + +# Assumptions and Limitations + +The core compaction model makes every assumption shared by the CLE family — the product form of the event tree, the cylindrical-pipe idealization +of a compaction flaw, the default critical shear stress ranges, the fixed failure pathway of a compaction flaw, and the tabulated progression +probabilities — each listed with its basis, effect, and limits in the +[Assumptions and Limitations](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/assumptions-and-limitations) chapter of the +CLE Common Methods manual. This chapter lists the assumptions the core compaction model adds or makes specific. Each states its engineering basis, +its effect on results, and the conditions under which it may not hold. Where a basis is still awaiting confirmation, the assumption +cross-references the input marker at its primary location. + +## Flaw Assessment + +1. **The likelihood of a continuous poorly compacted zone is captured by three factors: core compaction, the continuity of the section, and borrow + variability.** No other influence on the flaw is scored (see [Flaw Assessment](./04-flaw-assessment.mdx#factors)). + - *Engineering basis:* The risk-factor and likelihood-factor scheme of Fell et al. (2024) ; the basis of the + factors and weights is requested at marker IN-03 in [Flaw Assessment](./04-flaw-assessment.mdx#factors). + - *Effect on results:* The core compaction factor, with a weight of 3, moves the weighted sum by up to 9; the continuity factor, with a weight of + 2, by up to 6; borrow variability adds a constant 2.5. + - *When it may not hold:* Where site information bears on the flaw in ways the three factors do not represent; the risk team's estimate then + replaces the screening value. +2. **The compaction of the core is described by one of four qualitative categories, and Unknown is scored between Poorly compacted and Very poorly + compacted.** + - *Engineering basis:* Requested at markers IN-01 in [Input Parameters](./03-input-parameters.mdx#core-compaction-category) and IN-04 in + [Flaw Assessment](./04-flaw-assessment.mdx#compaction-factor). + - *Effect on results:* Selecting Unknown gives a flaw probability about 19 to 25 times that of Poorly compacted for the same section (see + [Resulting Flaw Probability](./04-flaw-assessment.mdx#resulting-flaw-probability)). + - *When it may not hold:* Where the core's compaction varies along its length or with depth; one category represents the whole core. +3. **The continuity of a poorly compacted zone is scored from the base width and width-to-height ratio of the section, and the less favorable of the + two governs.** + - *Engineering basis:* Requested at marker IN-05 in [Flaw Assessment](./04-flaw-assessment.mdx#continuity-factor). + - *Effect on results:* Without an observation, a narrow or slender section raises the flaw probability by a factor of about 2 to 3.5 per band + for a Poorly compacted, Very poorly compacted, or Unknown core. A well-compacted core stays negligible whatever the geometry, and under the + observation override the geometry does not affect the flaw probability. + - *When it may not hold:* Where the section is described in a length unit other than the one the base-width bands assume (see marker IN-05), or + where the low-permeability part of the section differs from the section described by the slope-segment tables; the flaw base width and height + can then be supplied (see [Input Parameters](./03-input-parameters.mdx#flaw-base-width-and-flaw-height)). +4. **Borrow variability is fixed at a likelihood factor of 2.5 for every site.** + - *Engineering basis:* Requested at marker IN-06 in [Flaw Assessment](./04-flaw-assessment.mdx#borrow-variability-factor). + - *Effect on results:* Borrow variability contributes the same 2.5 to every weighted sum, so it never distinguishes between sites. + - *When it may not hold:* Where the borrow sources are known to be uniform, the fixed 2.5 overstates the flaw probability; where they are known + to be highly variable, it understates it. +5. **The compaction category enters the flaw probability twice** — through its weight in the weighted sum and again through the flaw-continuity + probability (see [Flaw Assessment](./04-flaw-assessment.mdx#flaw-continuity)). + - *Engineering basis:* The flaw-continuity stage shared with the wall or cliff and foundation or abutment compaction models, documented in the + [Flaw-Continuity Stage](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#flaw-continuity-stage) + section of the CLE Common Methods manual. + - *Effect on results:* A well-compacted core has a negligible flaw probability whatever the section geometry, and the flaw probability spans + many orders of magnitude across the four categories. + - *When it may not hold:* Where compaction records conflict with field performance, such as observed seepage through a core rated well + compacted; the observation override then applies. +6. **An observation of embankment leakage or wet spots demonstrates the flaw and locates it.** The flaw probability is set to 1.0 and the base of the + flaw to the observed elevation (see [Flaw Assessment](./04-flaw-assessment.mdx#observation-override)). + - *Engineering basis:* Engineering judgment that an observation demonstrates the flaw, as for every CLE observation override (see the + [assumptions of the CLE Common Methods manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/assumptions-and-limitations#flaw)); + the meaning of the observed elevation is requested at marker IN-08 in + [Flaw Assessment](./04-flaw-assessment.mdx#observation-override). + - *Effect on results:* The SRP is governed entirely by the downstream nodes, and initiation, flow limitation, and the user's filter judgment are + all evaluated at the observed elevation. + - *When it may not hold:* Where the leakage or wet spots have another source, such as seepage through the foundation or along a conduit, or where + the observed exit lies below or above the flaw within the core. +7. **Without an observation, the base of the flaw is one third of the way from the normal pool to the crest, measured to the crest even when a lower + core top is described.** + - *Engineering basis:* The normal-pool heuristic shared with the abutment case of the foundation or abutment compaction model, documented in + [Compaction Models: Base of the Flaw](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/flaw-conventions#compaction-models-base-of-the-flaw) + in the CLE Common Methods manual. + - *Effect on results:* The SRP is negligible at pool levels at or below this elevation, and a wall is credited only if its top reaches it. A + core top below this elevation leaves the inputs inconsistent, and the analysis is not evaluated. + - *When it may not hold:* Where construction records or performance locate the poorly compacted zone. A zone lower in the core carries more + head at every pool level and begins to initiate at a lower pool, so the heuristic is unconservative there: the SRP at normal pool, for + example, is negligible even if the zone lies below normal pool. When leakage or wet spots locate the zone, the observation override should be + used. + +## Failure Pathway and Initiation + +8. **The user decides whether a filter intercepts the pathway, and the continuation probability is one value at every pool level.** Supplying the + filter and base-soil description states that a filter is present; the model does not compare the filter with the base of the flaw (see + [Event Tree](./05-event-tree.mdx#node-3-continuation)). + - *Engineering basis:* Engineering judgment: a compaction flaw is at one elevation, so the filter it meets does not change with the pool (see + the [assumptions of the CLE Common Methods manual](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/assumptions-and-limitations#failure-pathway-and-progression)). + - *Effect on results:* A supplied filter multiplies the SRP at every pool level by the continuation probability $P_{ce}$, which lowers it + whenever $P_{ce}$ is below 1.0. + - *When it may not hold:* Where the filter's top lies near the base of the flaw, or where the base of the flaw is uncertain; supplying a filter + that does not reach the flaw credits it wrongly, so the user should confirm that it reaches the base of the flaw. +9. **When a core section is supplied, it governs both the flaw scoring and the initiation analysis, whatever the embankment type.** + - *Engineering basis:* The pipe-length measurement of the Concentrated Leak Erosion Initiation toolbox, which measures across the impervious core + of a zoned embankment with very permeable outer zones (see + [Seepage Path Length](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#seepage-path-length) in the CLE + Common Methods manual); for the flaw scoring, the dimensions the continuity factor should measure are requested at marker IN-02 in + [Input Parameters](./03-input-parameters.mdx#flaw-base-width-and-flaw-height). + - *Effect on results:* A core narrower than the shell gives a shorter seepage path, a steeper gradient, and a higher initiation probability, and + can raise the continuity score. + - *When it may not hold:* Where the shells are not free draining and share the head loss with the core; the shell section or a supplied seepage + path length then describes the flaw better. +10. **The default initial pipe diameter is a triangular distribution from 2 mm to 5 mm, most likely 3 mm.** + - *Engineering basis:* See + [Initial Pipe Diameter](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/initiation#initial-pipe-diameter) in the CLE + Common Methods manual. + - *Effect on results:* The hydraulic shear stress is proportional to the diameter, so the range sets how high the pool must rise before + initiation becomes likely; larger diameters (a range shifted upward) lower that pool level. The critical shear stress and the seepage path + length also set that pool level. + - *When it may not hold:* Where the poorly compacted zone is expected to carry a larger or smaller initial opening; a site-specific distribution + should then be supplied. + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/07-output-and-interpretation.mdx b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/07-output-and-interpretation.mdx new file mode 100644 index 000000000..50658d0da --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/07-output-and-interpretation.mdx @@ -0,0 +1,104 @@ +--- +title: Output and Interpretation +--- + +import Citation from '@site/src/components/Citation'; +import CitationFootnote from '@site/src/components/CitationFootnote'; +import EquationNoRef from '@site/src/components/EquationNoRef'; +import NavContainer from '@site/src/components/NavContainer'; + + + +# Output and Interpretation + +The core compaction model reports the SRP at each evaluated pool level together with the probability of each of the eight nodes and the supporting +results of the flaw assessment and the initiation analysis. The results it shares with the other compaction models — the pool-independent node +values, the pool-dependent series, and the initiation results — are described in the +[Output and Interpretation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/output-and-interpretation) chapter of the CLE +Common Methods manual. This chapter describes the results specific to this model and how to read them. + +## Results + +**Pool-independent results:** + +- **Flaw probability** $P_{flaw}$ — Node 1, from the flaw assessment; 1.0 when the observation override applies. +- **Continuation probability** $P_{cont}$ — Node 3: the continuation method's result when filter inputs are supplied, otherwise 1.0. When the + continuation method is evaluated, its own results are reported with it — the governing base soil and method and the result for each base soil + (see the [Output and Interpretation](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/continuation-screening/v1.0/output-and-interpretation) chapter of the + Continuation (Filter Evaluation) Screening manual). +- **Roof-support probability** $P_{roof}$ — Node 4, the minimum across the embankment materials. +- **Crack-filling probability** $P_{nf}$ — Node 5, for the embankment type. +- **Flow-limitation probability** $P_{nl}$ — Node 6, after any wall below the base of the flaw has dropped out. + +**Pool-dependent series**, at every evaluated pool level: the pool level, the tailwater, the initiation probability, the flow-limitation, +unsuccessful-intervention, and breach probabilities (each the same at every pool level), and the SRP. Where there is no tailwater, the tailwater +entry is the base-of-flaw elevation, the level at which tailwater gives no submergence. + +**Flaw assessment results:** + +- The compaction, continuity, and borrow variability likelihood factors $LF_{comp}$, $LF_{cont}$, and $LF_{var}$. +- The weighted sum $\Sigma$, the raw flaw probability $P_{raw}$, and the flaw-continuity probability $P_{cf}$. +- The base width $W$, the height $H$, and the ratio $W/H$ that the continuity factor scored — the user-supplied values when given, otherwise those + of the section. +- The base-of-flaw elevation $z_f$, and whether the observation override applied. + +When the override applies with no compaction category, no scoring is performed, so the flaw probability rests on the observation alone. + +**Initiation results:** at each pool level, the upstream and downstream heads above the pipe invert, the hydraulic gradient, and the mean and 5th, +50th, and 95th percentiles of the hydraulic shear stress; the seepage path length; and the low, most likely, and high values of the critical shear +stress and initial pipe diameter distributions used. + +## Reading the Flaw Assessment + +The flaw assessment results show what sets the level of the curve: + +- **The compaction category** acts through two stages. Without an observation, a well-compacted core gives a negligible flaw probability and a + negligible curve at every pool level, whatever the other inputs; for the same section, the other three categories differ from each other by one to three orders of magnitude (see + [Resulting Flaw Probability](./04-flaw-assessment.mdx#resulting-flaw-probability)). Because Unknown scores above Poorly compacted, replacing + Unknown with a judged category of Poorly compacted lowers the flaw probability by a factor of about 19 to 25. +- **The continuity score** shows whether the section's width or its slenderness is raising the probability. The reported $W$ and $H$ show which + dimensions were scored; if they are not the intended dimensions of the low-permeability section, the flaw base width and height can be supplied. +- **Whether the observation override applied** shows whether the observation set the flaw probability to 1.0. With the override, the curve reflects the observed + elevation, not the heuristic. + +## Interpreting the System Response Curve + +The curve has the shape described for the compaction models in +[Interpreting the System Response Curve](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/output-and-interpretation#interpreting-the-system-response-curve) +in the CLE Common Methods manual. It is negligible at and below the base of the flaw and rises with pool level as the hydraulic gradient through the +pipe grows. Because only initiation varies with pool level, the curve approaches the product of the other seven nodes, + + + +as the initiation probability approaches 1.0. The pool level at which the curve begins to rise depends on the base of the flaw, the seepage path +length (measured from the section, or as supplied), the tailwater, and the critical shear stress and initial pipe diameter ranges; how close it comes to $\mathrm{SRP}_{max}$ within the evaluated pool range depends on how many +realizations initiate before the highest headwater. The node breakdown shows which node limits the curve (see +[Reading the Node Breakdown](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/output-and-interpretation#reading-the-node-breakdown) +in the CLE Common Methods manual). + +## Checking the Result + +The checks of +[Checking the Result](https://usace-rmc.github.io/RMC-Software-Documentation/docs/web-applications/system-response/cle-common-methods-screening/v1.0/output-and-interpretation#checking-the-result) in +the CLE Common Methods manual apply. In addition: + +- **Flaw probability** — without the observation override, the reported $P_{flaw}$ can be reproduced from the reported likelihood factors with + [Flaw Assessment](./04-flaw-assessment.mdx#resulting-flaw-probability), and should match the entry of the table for the reported category and + continuity score. +- **Base of the flaw** — without the override, the reported $z_f$ equals $z_{np} + (z_c - z_{np})/3$. A curve that rises from an unexpected pool + level can point to a normal pool or crest elevation on a different datum from the headwater series. +- **Filter credit** — a continuation probability below 1.0 means filter inputs were supplied; confirm that the filter reaches the reported base of + the flaw. +- **Wall credit** — when a top-of-wall elevation below $z_f$ is given, the reported flow-limitation probability $P_{nl}$ should equal the value + for the upstream elements other than walls (or 1.0 when no other element is listed). + +## Screening Results Relative to Detailed Analysis + +The core compaction model is a screening tool. Its result indicates whether concentrated leak erosion through poorly compacted core material +warrants detailed analysis; it is not a substitute for a detailed assessment. The compaction category, the continuity bands, the fixed borrow +variability score, the normal-pool heuristic for the flaw elevation, and the default critical shear stress and initial pipe diameter ranges are +screening values. Where the result is significant to a decision, the governing nodes should be re-examined with site-specific information — +construction records, compaction test data, erodibility testing, and the location of any observed seepage — and the detailed toolbox methods, the +methods of Fell et al. (2024) , and the judgment of the risk team should replace the screening values. + + diff --git a/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/_input-needed.md b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/_input-needed.md new file mode 100644 index 000000000..c08a60f70 --- /dev/null +++ b/docs/web-applications/system-response/cle-core-compaction-screening/v1.0/_input-needed.md @@ -0,0 +1,124 @@ +# Input Needed — Concentrated Leak Erosion Core Compaction Screening Technical Reference Manual (v1.0) + +Answer inline and return this file (or paste its contents into the conversation). Leave an +Answer blank to keep that marker in place. Do not renumber — the IDs tie each entry to its +admonition in the document. + +The bases of the methods this model shares with the CLE family (the log-linear interpolation of +the flaw-probability curves, the flaw-continuity curve, the normal-pool heuristic for the base +of the flaw, the default critical shear stress and initial pipe diameter ranges, and the +progression tables) are requested in the CLE Common Methods manual and are not repeated here. + +--- + +## IN-01 — Definition — `03-input-parameters.mdx` + +**Regarding:** The four core compaction categories (Well compacted, Poorly compacted, Very +poorly compacted, Unknown), offered without a definition. + +**Needed:** What construction practice or evidence each category represents (for example, +compaction equipment, lift thickness, moisture control, and density testing), or the table of +Fell et al. (2024) that defines them; and when Unknown should be selected rather than a judged +category, given that Unknown scores between Poorly compacted and Very poorly compacted. + +**Answer:** + +--- + +## IN-02 — Definition — `03-input-parameters.mdx` + +**Regarding:** The optional user-supplied flaw base width W and flaw height H, which replace the +dimensions derived from the embankment section in the continuity scoring only. + +**Needed:** What W and H are meant to represent and when they should be supplied in place of +the derived dimensions. + +**Proposed (unconfirmed):** W is the horizontal width of the section at its base, measured from +the upstream toe to the first drain or filter zone the pathway meets (or toe to toe when there +is none), and H is the height from the crest to the lower of the two toes. + +**Answer:** + +--- + +## IN-03 — Engineering Basis — `04-flaw-assessment.mdx` + +**Regarding:** The choice of the three scored factors and their risk factors (core compaction 3, +continuity 2, borrow variability 1). + +**Needed:** The table of Fell et al. (2024) from which the factors and weights are taken, or the +engineering-judgment attribution. + +**Answer:** + +--- + +## IN-04 — Engineering Basis — `04-flaw-assessment.mdx` + +**Regarding:** The compaction likelihood factors (Well compacted 1, Poorly compacted 3, Very +poorly compacted 4, Unknown 3.5). + +**Needed:** The source of the values, why no category scores 2, and why Unknown is scored at 3.5 +(above Poorly compacted) rather than at a central value; the table of Fell et al. (2024) they are +taken from, or the engineering-judgment attribution. + +**Proposed (unconfirmed):** Unknown is scored toward the poorly compacted end of the scale as a +conservative screening posture, so that a core whose compaction cannot be judged is not +credited as better compacted than the evidence supports. + +**Answer:** + +--- + +## IN-05 — Engineering Basis — `04-flaw-assessment.mdx` + +**Regarding:** The continuity bands (base width boundaries 50, 30, 15; width-to-height +boundaries 2, 0.75, 0.25) and the rule that the larger of the two scores governs. + +**Needed:** The source table or the engineering-judgment attribution, and the unit of the +base-width boundaries (the model applies them in whatever length unit the elevations use, with +no conversion). + +**Proposed (unconfirmed):** The base-width boundaries are in feet, so a user working in meters +should convert the section before running the model. + +**Answer:** + +--- + +## IN-06 — Engineering Basis — `04-flaw-assessment.mdx` + +**Regarding:** The borrow variability factor and its fixed likelihood factor of 2.5. + +**Needed:** What the factor represents physically, why it is fixed rather than selected by the +user, and the basis for the value of 2.5. + +**Answer:** + +--- + +## IN-07 — Engineering Basis — `04-flaw-assessment.mdx` + +**Regarding:** The raw flaw probability curve (weighted sum 6, 9, 11, 13, 18, 24 → negligible, +1e-4, 5e-4, 2e-3, 4e-2, 0.5). + +**Needed:** The figure or table of Fell et al. (2024) from which the values are taken, or the +engineering-judgment attribution, including the basis for anchoring the curve at a negligible +probability at a weighted sum of 6, below the lowest attainable sum of 7.5. + +**Answer:** + +--- + +## IN-08 — Definition — `04-flaw-assessment.mdx` + +**Regarding:** The leakage or wet-spot elevation, which becomes the base of the flaw (the invert +of a horizontal pipe through the core) under the observation override. + +**Needed:** Which elevation the user should enter (for example, the elevation of the observed +seepage exit on the downstream face, or the lowest wet spot when several are observed), and the +basis for taking it as the invert of a horizontal pipe through the core. + +**Answer:** + +--- diff --git a/src/docConfig.js b/src/docConfig.js index 3aa150ad4..922a2f52b 100644 --- a/src/docConfig.js +++ b/src/docConfig.js @@ -372,8 +372,9 @@ const docs = [ category: 'web-applications', software: 'system-response', doc_location: 'web-applications/system-response/cle-core-compaction-screening', - doc_name: 'CLE Core Compaction Screening Technical Reference Manual', - active: false, + doc_name: 'Concentrated Leak Erosion Core Compaction Screening Technical Reference Manual', + sidebar_label: 'Concentrated Leak Erosion Core Compaction Screening', + active: true, draft: true, }, { diff --git a/static/bibliographies/web-applications/system-response/cle-core-compaction-screening/v1.0/bib.json b/static/bibliographies/web-applications/system-response/cle-core-compaction-screening/v1.0/bib.json new file mode 100644 index 000000000..e5c80cf3b --- /dev/null +++ b/static/bibliographies/web-applications/system-response/cle-core-compaction-screening/v1.0/bib.json @@ -0,0 +1,17 @@ +[ + { + "citationKey": "Fell2024", + "entryType": "report", + "author": [ + "R. Fell", + "M.A. Foster", + "J. Cyganiewicz", + "R.R. Davidson", + "G.L. Sills" + ], + "title": "Methods for Estimating Probability of Failure of Embankment Dams by Internal Erosion and Piping (The Piping Toolbox 2024)", + "year": 2024, + "institution": "University of New South Wales, School of Civil and Environmental Engineering", + "report": "Report No. 470" + } +]