CN-122021164-A - Numerical calculation method for slope collapse process caused by toe scouring

CN122021164ACN 122021164 ACN122021164 ACN 122021164ACN-122021164-A

Abstract

The invention provides a numerical calculation method for a slope collapse process caused by toe flushing, which relates to the technical field of slope collapse numerical calculation, and specifically comprises the steps of constructing a finite element model of a toe flushing core area, determining a simulated flushing duration and a time interval, dividing a future window and tracing a history window; and combining the long-term and short-term memory network model with finite element simulation, predicting future window coupling basic parameters, water flow flushing strength, soil body critical shear strength and slope displacement through historical and current window data, fitting a polynomial curve of the water flow flushing strength and accumulated displacement, and determining flushing and collapse starting time to calculate the hysteresis time. The invention realizes a complete time sequence chain of history, current and future, precisely excavates the relation between the parameter evolution law and the scouring-collapsing time sequence, takes the quantized lag time as a hierarchical early warning time reference, and effectively solves the problem that the prior art can not provide effective time support for early warning deployment.

Inventors

ZHANG DONGFANG
LIU HAO
WANG WENLONG
LIU XIAOCHONG
WANG JINZHE

Assignees

中建八局第四建设有限公司

Dates

Publication Date: 20260512
Application Date: 20260131

Claims (7)

1. A numerical calculation method for a slope collapse process caused by toe scouring is characterized by comprising the following specific steps: s1, defining a toe flushing core area, constructing a finite element model of the toe flushing core area, determining a simulated flushing time length based on Froude number at the current time, and determining a simulated flushing time interval by combining the current time; s2, uniformly dividing the simulated flushing time interval into N continuous non-overlapping future windows, and tracing M window durations forward by taking the current moment as an end point to obtain a current window and a front M-1 history windows; S3, collecting coupling basic parameters of a current window and a first M-1 historical windows, inputting the coupling basic parameters into a finite element model, obtaining water flow scouring strength, soil body critical shear strength and slope displacement at the end moment of each window, inputting the coupling basic parameters of the current window and the first M-1 historical windows, the water flow scouring strength and the soil body critical shear strength into a long-short-period memory network model with training completed, outputting the coupling basic parameters of the next future window, repeating iteration until the coupling basic parameters of N future windows are obtained, inputting the coupling basic parameters into the finite element model, and obtaining the water flow scouring strength, the soil body critical shear strength and the slope displacement at the end moment of each future window; S4, fitting a polynomial curve of water flow flushing intensity based on the water flow flushing intensity at each future window ending moment, obtaining flushing starting moment when the water flow flushing intensity exceeds the soil body critical shear intensity for the first time, calculating accumulated displacement quantity from the 2 nd to the N th future window ending moment, fitting the polynomial curve of the accumulated displacement quantity, obtaining collapse starting moment when the accumulated displacement quantity exceeds the threshold value for the first time, and performing difference operation on the 2 starting moments to obtain the lag time.
2. The numerical calculation method for the shoreside slope collapse process caused by toe scouring according to claim 1, wherein the coupling basic parameters comprise a shoreside soil body parameter, a water flow power parameter and a shoreside slope topography parameter, the shoreside soil body parameter comprises cohesive force, an internal friction angle, dry density and porosity, the water flow power parameter comprises flow velocity, water depth and sand content, and the shoreside topography parameter comprises slope angle, slope height and slope length.
3. The method for calculating the numerical value of the slope collapse process caused by toe flushing according to claim 1, wherein the specific logic is as follows: selecting a plurality of characteristic points at equal intervals along the trend of the slope foot line, and taking the midpoint of the slope foot line as an origin Along the direction of the slope foot line The axis of the shaft is provided with a plurality of grooves, the vertical slope foot line points to the direction of the slope body The vertical upward direction of the shaft is Shaft, build three-dimensional coordinate system Collecting coordinates of all characteristic points on a toe line, inputting the coordinates into a finite element model, and completing space calibration of the toe line; for each characteristic point on the toe line Edge of the flange Extending the distance of the slope body side in the axial direction Edge of the flange Extending the water flow side distance in the axial direction Edge of the flange Height of extending in axial direction Edge of the flange Depth of extension in the negative axial direction ; Wherein, the Respectively points on the toe line A shaft(s), A shaft(s), Coordinate values in the axial direction; Wherein, the The value is 1/3 to 1/2 times of the slope height at the current moment, The value is 1.5 times to 2.5 times of the water depth under the current moment, The value is 1/2 to 1 times of the slope height at the current moment, The value is 1 to 1.5 times of the water depth at the current moment; sequentially connecting all the slope body side extending points corresponding to the characteristic points to form a slope body side boundary, and connecting all the water flow side extending points to form a water flow side boundary; Edge of the frame The axial direction is connected with the corresponding boundary points of the two end points of the slope toe line, forming a closed boundary at two ends of the region along And stretching all the two-dimensional boundaries in the axial direction to set height and depth to finally form a three-dimensional space range of the toe flushing core area.
4. The method for calculating the numerical value of the slope collapse process caused by toe flushing according to claim 1, wherein the simulated flushing time length is determined based on the froude number at the current time, and the specific logic is as follows: judging the flow state type according to the value of the Froude number, and assigning a corresponding flow state correction coefficient for each flow state type, wherein the specific rule is as follows: Froude number Judging that the flow state of water is slow flow, and assigning a flow state correction coefficient to be ; Froude number Judging the water flow state as critical flow, and assigning a flow state correction coefficient as ; Froude number Judging the flow state of water as the rapid flow, and assigning a flow state correction coefficient as ; Wherein, the ; Acquiring a corresponding flow state correction coefficient based on the flow state type of the Froude number at the current time; calculating the simulated flushing time by using the flow state correction coefficient and the initial flushing time according to the following formula: Wherein, the In order to simulate the duration of the flush, The initial flushing time length is the reference flushing time length of the toe under the critical flow working condition.
5. The method for calculating the numerical value of the slope collapse process caused by toe flushing according to claim 1, wherein the current moment is taken as an end point, and M window durations are traced back to obtain a current window and M-1 history windows, and the specific logic is as follows: a single history window of length At the current moment of The total time length of the forward trace is The corresponding time interval is Will be divided into Evenly dividing the window into M continuous non-overlapping sub-windows; will be close to the current time The last sub-window of (a) is used as the current window, and the time interval is that The rest M-1 sub-windows are the 1 st to M-1 st history windows from far to near in time, and the corresponding time intervals are respectively 。
6. The method for calculating the numerical value of the slope collapse process caused by toe flushing according to claim 1, wherein a polynomial curve of the water flow flushing intensity is fitted based on the water flow flushing intensity at the end time of each future window, and the specific logic is as follows: The end time of each future window is taken as an independent variable, and the water flow flushing intensity corresponding to the end time of each future window is taken as a dependent variable, so that a one-to-one water flow flushing intensity data set is constructed , wherein, Is the first The end time of each future window and the corresponding water flow flushing intensity, For the index of the future window(s), ; A polynomial curve of the water flow scouring intensity is constructed based on the water flow scouring intensity data set, and the polynomial curve has the following function expression: Wherein, the To be at the moment The fitting value of the corresponding water flow scouring intensity is lower, Are the first fitting coefficients to be solved, For the first order of the fit, , To simulate the time variable in the flushing time interval; solving fitting coefficients by adopting a least square method, taking the minimum sum of squares of residuals of polynomial fitting values and actual values of a dataset as a target, and solving partial derivatives of each first fitting coefficient to be solved based on a water flow scouring strength dataset until each partial derivative is equal to 0, so as to obtain specific values of all the first fitting coefficients to be solved; Substituting all specific values of the first fitting coefficient to be solved into a function expression of a water flow scouring strength polynomial curve to obtain a polynomial curve of the water flow scouring strength after fitting, and taking the moment when the water flow scouring strength of the polynomial curve exceeds the critical shear strength of the soil body for the first time as the scouring starting moment.
7. The method for calculating the numerical value of the slope collapse process caused by toe flushing according to claim 6, wherein the cumulative displacement amount from the 2 nd to the N th future window end time is calculated, and a polynomial curve of the cumulative displacement amount is fitted, and the specific logic is as follows: acquiring the displacement of the slope body corresponding to the end moments of N future windows, and marking as , wherein, Is the first Slope displacement at the end time of each future window; for each future window, calculating the accumulated value of the slope displacement of the end time of the future window and all the end times of the previous future windows to be used as the accumulated displacement of the end time of the future window; constructing a one-to-one cumulative displacement data set by taking the end time of each future window as an independent variable and the cumulative displacement corresponding to the end time of each future window as a dependent variable , wherein, Is the first The end time of each future window and the corresponding accumulated displacement; Constructing a polynomial curve of the accumulated displacement based on the accumulated displacement data set, wherein the polynomial curve has the following function expression: Wherein, the To be at the moment The corresponding cumulative displacement amount fitting value is then obtained, Are the second fitting coefficients to be solved, For the second order of the fit, ; Solving fitting coefficients by adopting a least square method, taking the minimum sum of squares of residuals of polynomial fitting values and actual values of the accumulated displacement data set as a target, and solving the fitting coefficients for each second to-be-solved based on the accumulated displacement data set Obtaining partial derivatives until each partial derivative is equal to 0, and obtaining specific numerical values of all second fitting coefficients to be solved; Substituting the specific values of all the second fitting coefficients to be solved into the functional expression of the polynomial curve of the accumulated displacement to obtain the polynomial curve of the accumulated displacement after fitting, and taking the moment of the first exceeding of the threshold value of the accumulated displacement in the polynomial curve as the collapse starting moment.

Description

Numerical calculation method for slope collapse process caused by toe scouring Technical Field The invention relates to the technical field of calculation of a collapse value of a bank slope, in particular to a calculation method of a collapse process of the bank slope caused by toe scouring. Background The flushing of the slope toe is one of the core causes for inducing the collapse of the bank slope, especially the continuous flushing of water flow to the slope toe of the bank slope on the periphery of water areas such as rivers, lakes and the like can cause the damage of a slope body supporting structure, thereby causing collapse disasters and threatening flood control safety, river channel shipping and coastal engineering facility safety. Along with the development of numerical simulation technology, numerical methods such as finite elements and the like are widely applied to simulation analysis of a slope collapse process caused by toe flushing, and become an important means for evaluating the stability of a slope. In engineering practice, after the water flow scouring strength exceeds the critical shear strength of soil body for the first time, the bank slope does not collapse immediately, but a hysteresis process of scouring accumulation, slope deformation development and final instability exists. The existing numerical calculation method for the slope collapse process caused by toe flushing can realize basic simulation of the flushing and collapse processes, but has the design defects that the effective flushing time or collapse instability time is judged independently, the water flushing strength is not definitely used as a core time node for the first time, the pertinence judgment logic of the collapse starting time is not formed, the time difference between the flushing and collapse starting time cannot be captured accurately, the delay time cannot be quantized, and an operable time reference cannot be provided for the establishment of an early warning scheme finally. The above information disclosed in the background section is only for enhancement of understanding of the background of the disclosure and therefore it may include information that does not form the prior art that is already known to a person of ordinary skill in the art. Disclosure of Invention The invention aims to provide a numerical calculation method for a shoreside collapse process caused by toe scouring, so as to solve the problems in the background art. In order to achieve the above purpose, the present invention provides the following technical solutions: A numerical calculation method for a slope collapse process caused by toe scouring specifically comprises the following steps: s1, defining a toe flushing core area, constructing a finite element model of the toe flushing core area, determining a simulated flushing time length based on Froude number at the current time, and determining a simulated flushing time interval by combining the current time; s2, uniformly dividing the simulated flushing time interval into N continuous non-overlapping future windows, and tracing M window durations forward by taking the current moment as an end point to obtain a current window and a front M-1 history windows; S3, collecting coupling basic parameters of a current window and a first M-1 historical windows, inputting the coupling basic parameters into a finite element model, obtaining water flow scouring strength, soil body critical shear strength and slope displacement at the end moment of each window, inputting the coupling basic parameters of the current window and the first M-1 historical windows, the water flow scouring strength and the soil body critical shear strength into a long-short-period memory network model with training completed, outputting the coupling basic parameters of the next future window, repeating iteration until the coupling basic parameters of N future windows are obtained, inputting the coupling basic parameters into the finite element model, and obtaining the water flow scouring strength, the soil body critical shear strength and the slope displacement at the end moment of each future window; S4, fitting a polynomial curve of water flow flushing intensity based on the water flow flushing intensity at each future window ending moment, obtaining flushing starting moment when the water flow flushing intensity exceeds the soil body critical shear intensity for the first time, calculating accumulated displacement quantity from the 2 nd to the N th future window ending moment, fitting the polynomial curve of the accumulated displacement quantity, obtaining collapse starting moment when the accumulated displacement quantity exceeds the threshold value for the first time, and performing difference operation on the 2 starting moments to obtain the lag time. Further, the coupling basic parameters comprise a shore soil body parameter, a water flow power parameter and a shore topography parameter, wherein the shore soil