CN-122021041-A - Dynamic expansion evaluation method for dike breach based on dam body permeability

CN122021041ACN 122021041 ACN122021041 ACN 122021041ACN-122021041-A

Abstract

The invention discloses a dam breach dynamic expansion evaluation method based on dam permeability, which comprises the steps of S1, constructing a simplified model of a breach slope collapse body based on the structure of the breach slope collapse body, defining the physical form of the breach slope collapse body, dividing a collapse stress area at the same time, obtaining a breach dynamic expansion evaluation parameter, S2, calculating the maximum shear stress on a potential damage surface, the positive stress on a potential damage surface with unit width and the soil shear strength by adopting the breach dynamic expansion evaluation parameter, S3, calculating the collapse body width according to the calculation result of S2, constructing a shear damage criterion, estimating the collapse body width when a shear damage occurs node, S4, carrying out dynamic expansion evaluation of the dike breach based on the collapse body width when the shear damage occurs, taking the permeability parameter as a key variable, making up the defect that the existing evaluation method ignores or is difficult to quantify the influence of seepage inside the soil, and only needing a group of parameters, and directly calculating the collapse body width, and inputting the parameters are few and clear.

Inventors

LIU ZHENZHEN
HUANG XIXUAN
SI KAI
LIU YINGRAN

Assignees

郑州工程技术学院

Dates

Publication Date: 20260512
Application Date: 20260207

Claims (10)

1. The dynamic expansion evaluation method for the dike breach based on the dam permeability is characterized by comprising the following steps of: S1, constructing a simplified model of a collapsible body of a crumple side slope based on the collapsible body structure of the crumple side slope, defining the physical form of the collapsible body of the crumple side slope, dividing a collapse stress area at the same time, and obtaining a crumple dynamic expansion evaluation parameter; s2, calculating the maximum shear stress on the potential damaged surface, the normal stress on the potential damaged surface with unit width and the soil shear strength by adopting the dynamic expansion evaluation parameters of the crumple, wherein the normal stress is calculated based on the permeability of the dam body; s3, calculating the width of the collapse body according to the calculation result of the S2, constructing a shear failure criterion, and predicting the width of the collapse body when a shear failure occurs at the node; And S4, dynamically expanding and evaluating the dike breach based on the width of the collapse body when the shear damage occurs.
2. The dynamic expansion evaluation method of the dike breach based on the dam permeability is characterized in that defining the physical form of the breach slope collapse body and dividing collapse stress areas simultaneously comprises dividing the collapse body into a plurality of areas from top to bottom according to the structural shape and the permeability, wherein the plurality of areas comprise an area above a water surface line of the collapse body, an area between the water surface of the collapse body and the critical position of the breach and the collapse body breach area, and the evaluation parameters of the dynamic expansion of the breach comprise the height of the dam body, the average water depth in the breach, the erosion height at the breach of the collapse body and the soil body weight of the plurality of areas.
3. The dynamic expansion evaluation method for the dike breach based on the dam permeability according to claim 1 or 2 is characterized in that the shear failure criterion is that the maximum shear stress along the shear failure surface in the collapse body caused by driving force is less than or equal to the shear strength of soil.
4. The method for dynamically expanding and evaluating the breach of a dike based on the permeability of the dike according to claim 1 or 2, wherein the maximum shear stress on the potential damage surface comprises the self weight of the collapsed dike and the water pressure born by the vertical of the collapsed dike, and the maximum shear stress is calculated by subtracting the difference value of the ratio of the self weight of the collapsed dike to the height of the dike from the ratio of the water pressure born by the vertical of the collapsed dike to the height of the dike.
5. The dynamic expansion evaluation method of the dike breach based on the dam permeability of claim 4, wherein the collapse body dead weight calculation comprises the following steps: Wherein H is the height of a dam body, H w is the average water depth in a breach, H e is the erosion height at a breach of a collapse body, l e is the width of the collapse body, the collapse body is divided into three areas according to the shape and the permeability characteristics, the first area is a rectangular area above a water surface line, the soil body weight of the first area is gamma 1 , the second area is a rectangular area of the collapse body between the position below the water surface and the critical position of the breach, the soil body weight of the second area is gamma 2 , the third area is an underwater breach triangular area of the collapse body, the soil body weight of the third area is the same as that of the second area, and gamma 2 is taken.
6. The method for dynamically expanding and evaluating the breach of a dike based on the permeability of a dam body according to claim 4, wherein the calculation of the water pressure born by the vertical direction of the collapse body comprises the following steps: Gamma w is the water gravity, h w is the average water depth in the crumple, h e is the erosion height at the collapse body notch, and l e is the collapse body width.
7. The method for dynamically expanding and evaluating the dam breach based on the permeability of a dam body according to claim 1, wherein the normal stress on a potential damage surface of a unit width is a ratio of a normal force of the unit width to the height of the dam body applied to the potential damage surface, the normal force of the unit width is composed of three parts of water pressures respectively represented by U N1 ,U N2 and U N3 , U N1 is a unit width pressure acting on a collapse body and generated by water pressure at the lower part of the breach, U N2 is a unit width water pressure acting on the outer side of the collapse body and generated by water pressure inside the breach, and U N3 is a unit width water pressure acting on the side of the collapse body away from the breach and generated by water pressure inside a soil body of the dam body.
8. The method for dynamically expanding and evaluating the breach of the dike based on the permeability of the dam body according to claim 7, wherein the calculation of U N1 ,U N2 and U N3 comprises the following steps: Wherein, alpha represents the permeability of the dam body, the size of U N3 is determined by the permeability of the dam body, h w is the average water depth in the crumple, h e is the erosion height at the notch of the collapse body, and gamma w is the water gravity.
9. The dynamic expansion evaluation method for the dike breach based on the dam permeability of claim 3, wherein the soil shear strength calculation comprises the following steps: Wherein c 'is the effective cohesive force of the soil body, phi' is the effective internal friction angle of the soil body, and the two are related to the soil body material for damming, and are obtained through experiments, and sigma n is the normal stress on the potential damage surface of the unit width.
10. The method for dynamically expanding and evaluating the dike breach based on the dam permeability according to claim 1, wherein the calculating of the width of the collapse body comprises the following steps: wherein, alpha represents the permeability of the dam body, c 'is the effective cohesive force of the soil body, gamma w is the weight of water, H w is the average water depth in the burst opening, H is the height of the dam body, and phi' is the effective internal friction angle of the soil body; The method comprises the steps of dividing a collapse body into three areas according to the shape and permeability characteristics, wherein h e is the erosion height of a notch of the collapse body, the first area is a rectangular area above a water surface line, the soil body weight of the area is gamma 1 , the second area is a rectangular area between the position below the water surface of the collapse body and the critical position of a bursting opening, the soil body weight of the area is gamma 2 , the third area is an underwater bursting opening triangular area of the collapse body, the soil body weight of the area is the same as that of the second area, and gamma 2 is taken.

Description

Dynamic expansion evaluation method for dike breach based on dam body permeability Technical Field The invention relates to the technical field of flood control, in particular to a dynamic expansion evaluation method for a dike breach based on dam permeability. Background The dam body breaking quick and accurate assessment is realized, the decision safety and effectiveness are ensured, and the method is an effective way for reducing flood risks. At present, the dam breach expansion evaluation method mainly comprises a parameterized model based on regression analysis, a semi-parameterized model and a numerical model based on a physical mechanism. The parameterized and semi-parameterized crumple expansion model is based on historical crumple expansion statistical data analysis, and can only give final crumple width, and can not dynamically evaluate crumple expansion. Meanwhile, the model parameters only relate to physical parameters such as the height, the width and the like of the dam body, and important influencing factors such as the mechanical property, the permeability and the like of the dike building material cannot be fully considered. The numerical model based on the physical mechanism needs to adopt large finite element software to carry out the hydrodynamics simulation, combines slope stability numerical simulation analysis and the like, has high calculation force requirement, consumes long time in the calculation process, and is difficult to meet the emergency response requirement. The patent with publication number CN115935651A provides a complete process crumple development calculation method which has few parameters and is easy to implement, and the physical property and the practicability of simulation are improved. But neglect or hardly quantify the effect of seepage inside the soil. The patent publication CN119761833a requires the construction of a complete numerical model, relies on a large amount of terrain, hydrology, boundary condition data, and performs long-term simulation calculations. And therefore less efficient. Based on the above, the invention aims to establish a dynamic evaluation method for dam body permeability parameters-breach expansion, rapidly evaluate the breach expansion width, and provide algorithm support for dam body breach expansion evaluation and risk coping decision. Disclosure of Invention The invention provides a dynamic expansion evaluation method for a dike breach based on dam permeability, which is suitable for predicting the breach process of a homogeneous soil dike under the condition of high water level in a flood season in real time and provides a quantitative basis for risk coping decision. The invention provides a dynamic expansion evaluation method of a dike breach based on dam permeability, which comprises the following steps of S1, constructing a simplified model of the collapsible of the breach slope based on the collapse structure of the breach slope, defining the physical form of the collapsible of the breach slope, dividing collapse stress areas and obtaining dynamic expansion evaluation parameters of the breach, S2, calculating the maximum shear stress on a potential damage surface, the normal stress on a potential damage surface with unit width and the soil shear strength by adopting the dynamic expansion evaluation parameters of the breach, wherein the normal stress is calculated based on the dam permeability, S3, calculating the width of the collapsible according to the calculation result of S2, constructing a shear damage criterion, estimating the width of the collapsible when a shear damage occurs, and S4, carrying out dynamic expansion evaluation of the dike breach based on the width of the collapsible when the shear damage occurs. The dam body permeability-based dynamic expansion evaluation method for the dike breach comprises the steps of defining the physical form of the breach slope collapse body, dividing collapse stress areas, dividing the collapse body into a plurality of areas from top to bottom according to the structural shape and permeability, wherein the plurality of areas comprise an area above the water surface of the collapse body, an area between the water surface of the collapse body and the critical position of the breach and the breach area of the collapse body, and the dynamic expansion evaluation parameters of the breach comprise the height of the dam body, the average water depth in the breach, the erosion height of the breach of the collapse body and the soil weight of the plurality of areas. The shearing damage criterion is that the maximum shearing stress along the shearing damage surface in the collapse body caused by the driving force is less than or equal to the shearing strength of the soil body. The maximum shear stress on the potential damaged surface comprises the dead weight of the collapse body and the water pressure born by the vertical direction of the collapse body, and the maximum shear stress is calcul