CN-122021449-A - Method and related device for simulating overtopping and breaking of clay dike

CN122021449ACN 122021449 ACN122021449 ACN 122021449ACN-122021449-A

Abstract

The invention discloses a method and a related device for simulating the overtravel and break of a clay dike, which are used for correcting the vertical erosion rate of a grid node according to the gradient of the grid node, the erosion correction coefficient of the abrupt bank and the gradient threshold of an identified abrupt bank, accurately simulating the unique vertical abrupt bank tracing erosion process of the clay dike, increasing the burst width increment caused by gravity collapse when calculating the burst width, accurately simulating the nonlinear width burst caused by the conversion from hydraulic erosion to gravity collapse, adopting random disturbance amplitude to simulate the erosion response of soil bodies at different positions, considering the heterogeneity of the clay dike, and having higher prediction accuracy on the break.

Inventors

Zhang Meiman
MA ZICAI
CHEN JIERONG
WANG LINGLING
WU MENGTIAN
ZHU HAI
XU JIN
HE WEI
WANG DUO
GU PENG

Assignees

河海大学

Dates

Publication Date: 20260512
Application Date: 20260210

Claims (10)

1. A method for simulating the break-over of the overtravel of a clay dike is characterized in that the longitudinal section of the dike body is discretized into grid nodes with fixed intervals, and the break-over process is subjected to synchronous iterative simulation; Wherein, the process of each simulation comprises: calculating the bottom shear stress of the water flow applied to the soil body surface at the current time point according to the width of the breach obtained by the simulation at the previous time point and the updated elevation of the longitudinal section of the dam body; Calculating the vertical erosion rate of the grid node according to the bottom tangential stress, and correcting the vertical erosion rate of the grid node according to the gradient of the grid node, the erosion correction coefficient of the steep bank and the gradient threshold of the identification steep bank, wherein the erosion response of soil bodies at different positions is simulated by adopting random disturbance amplitude when the vertical erosion rate is calculated; updating the elevation of the longitudinal section of the dam body according to the corrected vertical erosion rate; Judging a collapse stage of the current time point according to the updated elevation of the longitudinal section of the dam body, and calculating the width of the collapse mouth of the current time point according to the judging result, wherein when the width of the collapse mouth is calculated, if the collapse stage of the current time point is a gravity collapse leading stage, the increment of the collapse mouth width and the increment of the collapse mouth caused by gravity collapse are increased.
2. The method of claim 1, wherein calculating the bottom shear stress applied to the soil surface by the current time point water flow based on the width of the breach obtained by the last time point simulation and the updated elevation of the longitudinal section of the dam comprises: Calculating the discharge flow of the breach at the current time point according to the width of the breach obtained by the simulation at the last time point and the elevation of the bottom plate of the breach in the elevation of the longitudinal section of the updated dam body; According to the leakage flow of the crumple at the current time point, calculating the water depth and the flow velocity corresponding to the grid node; And calculating the bottom shear stress of the water flow applied to the soil surface at the current time point according to the water depth and the flow velocity.
3. The method of claim 2, wherein the water depth and flow rate are calculated as: ; ; Wherein h and v are water depth and flow velocity respectively, n is a Manning roughness coefficient, q is a single wide flow obtained by changing the leakage flow of a crumple and the width of the crumple, and S 0 is the gradient of a bottom slope; The calculation formula of the bottom shear stress is: ; In the formula, G is gravity acceleration, and ρ is water density.
4. The method of claim 1, wherein the vertical erosion rate of the grid node is calculated by the formula: ; Wherein E v is the vertical erosion rate, K d is the erosion coefficient of the soil body, Is the shear stress of the bottom part, For a critical start-up shear stress, Representation of To follow uniform distribution Delta is the random disturbance amplitude.
5. The method of claim 1, wherein the vertical erosion rate of the grid node is modified by: ; wherein E v is the vertical erosion rate, For the corrected E v ,λ headcut to be the erosion correction coefficient of the steepness, S 0,i is the corresponding gradient of the grid node, and S crit is the gradient threshold for identifying the steepness.
6. The method of claim 1, wherein the dam longitudinal section elevation is updated by the formula: ; In the formula, For the elevation of the dam body longitudinal section corresponding to the ith grid node after updating, Z i is the elevation of the dam body longitudinal section corresponding to the ith grid node before updating, Δt is the time step, and E v,i is the vertical erosion rate corresponding to the ith grid node.
7. The method of claim 1, wherein determining the collapse stage at the current point in time based on the updated elevation of the longitudinal section of the dam comprises: Calculating the stability safety coefficient of the side slope according to the updated elevation of the longitudinal section of the dam body; If the current time point is greater than the soil body saturation starting time and the slope stability safety coefficient is smaller than the safety threshold, judging that the current time point is in the gravity collapse leading stage, otherwise, the current time point is in the hydraulic erosion leading stage.
8. The method of claim 1, wherein calculating the vent width at the current time point is formulated as: ; Wherein B is the width of the crumple, t is the time point, K d is the erosion coefficient of soil body for the hydraulic side erosion rate, Is the shear stress of the bottom part, For critical onset shear stress, alpha is the coefficient of lateral erosion, To increase the burst width of the crumple due to gravity collapse, Is the collapse magnification factor.
9. A cohesive soil dike overtopping burst simulator, comprising: the iteration simulation module is used for dispersing the longitudinal section of the dam body of the earth dam into grid nodes with fixed intervals and carrying out equal-time iteration simulation on the breaking process; Wherein, the process of each simulation comprises: calculating the bottom shear stress of the water flow applied to the soil body surface at the current time point according to the width of the breach obtained by the simulation at the previous time point and the updated elevation of the longitudinal section of the dam body; Calculating the vertical erosion rate of the grid node according to the bottom tangential stress, and correcting the vertical erosion rate of the grid node according to the gradient of the grid node, the erosion correction coefficient of the steep bank and the gradient threshold of the identification steep bank, wherein the erosion response of soil bodies at different positions is simulated by adopting random disturbance amplitude when the vertical erosion rate is calculated; updating the elevation of the longitudinal section of the dam body according to the corrected vertical erosion rate; Judging a collapse stage of the current time point according to the updated elevation of the longitudinal section of the dam body, and calculating the width of the collapse mouth of the current time point according to the judging result, wherein when the width of the collapse mouth is calculated, if the collapse stage of the current time point is a gravity collapse leading stage, the increment of the collapse mouth width and the increment of the collapse mouth caused by gravity collapse are increased.
10. A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform the method of any of claims 1-8.

Description

Method and related device for simulating overtopping and breaking of clay dike Technical Field The invention relates to a method and a related device for simulating the overtopping and breaking of a viscous earth dike, and belongs to the field of numerical simulation of dam break. Background Earth-rock dams and river embankments are key links of flood control engineering systems, and flood break caused by overtopping often results in disastrous flood consequences. Unlike the uniform layer-by-layer erosion of non-clay soils (e.g., sandy soil), clay dikes exhibit very complex erosion dynamics under the action of a flood stream. Large scale field trials have shown that the process of breakup of clay dikes is not monotonic linear erosion, but rather exhibits significant "stepwise" and "burstiness", wherein the initial stage (i.e., the dominant stage of hydraulic erosion) is manifested as a typical steep-ridge trace-out, and the later stage (i.e., the dominant stage of gravity collapse) is converted to intermittent collapse that is dominant by gravity. This physical mechanism of destabilization from continuous hydraulic erosion to discrete rock and soil is a key contributor to dam-break flood peak surge. The existing simulation mostly adopts regular geometric generalization, is difficult to accurately simulate the unique vertical abrupt bank tracing flushing process of the clay dike and the nonlinear width sudden increase problem caused by the conversion from hydraulic erosion to gravity collapse, and is mostly based on homogeneous soil body assumption, ignores the heterogeneity of natural or filled dike, and causes the problem of larger deviation in burst prediction. Disclosure of Invention The invention provides a method and a related device for simulating the overtopping and breaking of a clay dike, which solve the problems disclosed in the background art. According to one aspect of the application, a method for simulating the overtopping and breaking of a viscous soil dike is provided, wherein the longitudinal section of a dam body of the soil dike is discretized into grid nodes with fixed intervals, and the breaking process is subjected to synchronous iterative simulation; Wherein, the process of each simulation comprises: calculating the bottom shear stress of the water flow applied to the soil body surface at the current time point according to the width of the breach obtained by the simulation at the previous time point and the updated elevation of the longitudinal section of the dam body; Calculating the vertical erosion rate of the grid node according to the bottom tangential stress, and correcting the vertical erosion rate of the grid node according to the gradient of the grid node, the erosion correction coefficient of the steep bank and the gradient threshold of the identification steep bank, wherein the erosion response of soil bodies at different positions is simulated by adopting random disturbance amplitude when the vertical erosion rate is calculated; updating the elevation of the longitudinal section of the dam body according to the corrected vertical erosion rate; Judging a collapse stage of the current time point according to the updated elevation of the longitudinal section of the dam body, and calculating the width of the collapse mouth of the current time point according to the judging result, wherein when the width of the collapse mouth is calculated, if the collapse stage of the current time point is a gravity collapse leading stage, the increment of the collapse mouth width and the increment of the collapse mouth caused by gravity collapse are increased. Further, calculating the bottom shear stress of the water flow at the current time point applied to the soil surface according to the width of the breach obtained by the simulation at the previous time point and the updated elevation of the longitudinal section of the dam body, wherein the method comprises the following steps: Calculating the discharge flow of the breach at the current time point according to the width of the breach obtained by the simulation at the last time point and the elevation of the bottom plate of the breach in the elevation of the longitudinal section of the updated dam body; According to the leakage flow of the crumple at the current time point, calculating the water depth and the flow velocity corresponding to the grid node; And calculating the bottom shear stress of the water flow applied to the soil surface at the current time point according to the water depth and the flow velocity. Further, the calculation formula of the water depth and the flow rate is as follows: ; ; Wherein h and v are water depth and flow velocity respectively, n is a Manning roughness coefficient, q is a single wide flow obtained by changing the leakage flow of a crumple and the width of the crumple, and S 0 is the gradient of a bottom slope; The calculation formula of the bottom shear stress is: ; In the formula, G is gravity accel