An impervious control system for earth and rockfill cofferdams

Abstract

The present application relates to the technical field of hydraulic engineering, and more particularly to a seepage control system for earth-rock cofferdams. The present application periodically collects external hydro-meteorological data and internal structural response data of the cofferdam through sensors based on a monitoring unit; a multi-field coupling model is established based on the finite element method through a model construction unit, dynamically coupling wave load, tidal level and seepage pressure field; the minimum cofferdam top elevation is determined by comparing the difference between the minimum safety factor and the preset safety factor based on a decision unit; and the minimum cofferdam top elevation is input into the multi-field coupling model based on an analysis unit to obtain the maximum value of the hydraulic slope of the backwater slope escape point within a third preset time period, the seepage state is determined based on the maximum value, and the related parameters are adjusted based on the seepage state. The present application reduces the leakage rate of earth-rock cofferdams through real-time monitoring, prediction and active control of cofferdam seepage risk.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydraulic engineering, and in particular to a seepage control system for earth-rock cofferdams. BACKGROUND

[0002] In the marine environment, the cofferdam needs to withstand typhoons, astronomical tides, storm surges and other extreme loads. The existing design method mostly uses static load design, which cannot accurately simulate the complex interaction of wave load, dynamic water level change and internal seepage field of the cofferdam under the coupling action of typhoons, astronomical tides and storm surges. This leads to excessive design safety margin, resulting in economic waste, or underestimation under extreme working conditions, which poses a risk of overtopping and cofferdam collapse.

[0003] Chinese Patent Publication No. CN114969933A discloses a method for constructing a parameterized model of an earth-rock cofferdam, an electronic device and a storage medium. The method includes constructing a topographic surface of the earth-rock cofferdam filling area; determining the arrangement position of the cofferdam center line and drawing the cofferdam center line at the arrangement position; determining the cofferdam crest design elevation; according to the drawing standard, changing the characteristics and style of the longitudinal section drawing, customizing the required longitudinal section drawing style set, and then combining the cofferdam crest design elevation to draw the longitudinal section drawing and the cofferdam crest design elevation control line on the longitudinal section drawing; constructing a cofferdam parameterized cross section; creating a cross section assembly, loading the cofferdam parameterized cross section and inserting it into the cross section assembly; when the geometric parameters of the cofferdam parameterized cross section meet the requirements, selecting the cofferdam center line, the cofferdam crest design elevation control line and the cofferdam parameterized cross section drawn or constructed in the cofferdam creation interface to generate a parameterized model of the earth-rock cofferdam.

[0004] As can be seen, the prior art has the following problems: the load calculation under extreme working conditions and the construction optimization of the cofferdam crest elevation lack systematic theoretical support, resulting in high seepage rate. SUMMARY

[0005] To this end, the present application provides a seepage control system for earth-rock cofferdams to overcome the problem of lack of systematic theoretical support for load calculation under extreme working conditions and construction optimization of cofferdam crest elevation in the prior art, thereby reducing seepage rate.

[0006] To achieve the above-mentioned purpose, the present application provides a seepage control system for earth-rock cofferdams, comprising:

[0007] a monitoring unit for periodically monitoring a data set based on a sensor set, including a set of hydro-meteorological sensors for collecting external environmental data of the cofferdam and a set of structural response sensors for collecting internal state data of the cofferdam;

[0008] a model construction unit connected with the monitoring unit, configured to construct a multi-field coupling model based on a finite element method, wherein the multi-field coupling model dynamically and iteratively couples wave load, tidal level and seepage pressure field in the data set within a first preset time length;

[0009] a decision unit connected with the monitoring unit and the model construction unit, configured to calculate a difference between a minimum safety factor determined by inputting the data set and hydrological condition predicted after a second preset time length into the multi-field coupling model and a preset safety factor, and determine the minimum cofferdam top elevation based on a comparison result of the difference and a preset threshold;

[0010] an analysis unit connected with the decision unit, configured to input the minimum cofferdam top elevation into the multi-field coupling model to obtain a maximum value of hydraulic gradient of a back-slope escape point within a third preset time length, determine a seepage prevention state based on the maximum value, adjust the preset threshold based on the seepage prevention state, and adjust the first preset time length based on the seepage prevention state after the preset threshold is adjusted.

[0011] Further, the model construction unit further comprises: a boundary condition driving module configured to receive wave load time series data and tidal level difference time series data, and convert the wave load time series data and the tidal level difference time series data into dynamic boundary conditions for seepage field calculation; a seepage field analysis module connected with the boundary condition driving module, configured to calculate a seepage control equation based on the dynamic boundary conditions to determine pore water pressure distribution and phreatic line position inside the cofferdam; a stress field analysis module connected with the seepage field analysis module, configured to convert the pore water pressure distribution into seepage volume force acting on soil skeleton and determine displacement field and stress field of the cofferdam based on the external environment data; a coupling module connected with the seepage field analysis module and the stress field analysis module, respectively, configured to calculate volume strain of each finite element unit based on the stress field and the displacement field, and periodically update porosity of the corresponding finite element unit based on the volume strain of each finite element unit, and calculate the corresponding permeability coefficient; and a feedback module connected with the seepage field analysis module and the coupling module, respectively, configured to feed back the permeability coefficient to the seepage field analysis module, and repeat iteration of the coupling module at least once every time step within the first preset time length until the difference between the displacement fields of two consecutive iterations is less than a tolerance or the total iteration time is equal to the first preset time length.

[0012] Further, the decision unit further comprises a judging module configured to run the multi-field coupling model based on a set initial cofferdam top elevation to determine a minimum safety factor; an adjusting module connected with the judging module and configured to adjust the initial cofferdam top elevation based on a comparison result of the minimum safety factor and a preset safety factor; and an iteration module connected with the judging module and the adjusting module respectively, and configured to cyclically execute the judging module and the adjusting module at least once based on the adjusted initial cofferdam top elevation until the difference between the minimum safety factor determined at the iteration and the preset safety factor is greater than zero and less than or equal to the preset threshold value, and to determine the cofferdam top elevation determined after the iteration is stopped as the minimum cofferdam top elevation.

[0013] Further, the analysis unit is further configured to, in a case where the impermeability state is determined to be unqualified, calculate a variance of a maximum value of the water-side slope out escape point hydraulic gradient in the third preset time length; and to, in a case where the variance is less than a preset variance, adjust the preset threshold value based on a ratio of the variance to the preset variance; wherein the impermeability state is determined to be unqualified in a case where the maximum value of the water-side slope out escape point hydraulic gradient in the third preset time length is greater than a preset value.

[0014] Further, the analysis unit is further configured to reduce the preset threshold value based on the ratio of the variance to the preset variance, and the reduction amplitude of the preset threshold value is inversely proportional to the ratio.

[0015] Further, the analysis unit is further configured to, in a case where the impermeability state is unqualified after the preset threshold value is adjusted, repeatedly adjust the preset threshold value at least once until the adjustment times is less than a preset number of times and the impermeability state is qualified or the adjustment times is equal to the preset number of times, and to, in a case where the impermeability state is unqualified after the adjustment is stopped, plot a time-hydraulic gradient curve based on the water-side slope out escape point hydraulic gradient at the plurality of times in the third preset time length; and to calculate an integral of the curve and, in a case where the integral is greater than a preset integral, adjust the tolerance based on a ratio of the integral to the preset integral.

[0016] Further, the analysis unit is further configured to reduce the tolerance based on the ratio of the integral to the preset integral, and the reduction amplitude of the tolerance is proportional to the ratio.

[0017] Further, the analysis unit is further configured to, in a case where the impermeability state is unqualified after the tolerance is adjusted, obtain a difference value of the displacement field corresponding to each two consecutive iterations in the first preset time length; and to calculate an average value of absolute values of the plurality of difference values and, in a case where the average value is greater than a preset average value, adjust the first preset time length based on a ratio of the average value to the preset average value.

[0018] Further, the analysis unit is also used to increase the first preset time length based on the ratio of the average value to the preset average value, and the increase amplitude of the first preset time length is proportional to the ratio.

[0019] Further, the analysis unit is also used to acquire the number of times that the maximum value of the water slope at the backwater slope out escape point within the third preset time length is greater than a preset value at multiple historical moments in the case that the anti-seepage state after the adjustment of the first preset time length is unqualified; and the analysis unit is also used to decrease the period of monitoring the data set by the sensor group based on the difference between the number of times and the preset number of times in the case that the number of times is greater than the preset number of times, and the decrease amplitude of the period is proportional to the difference.

[0020] Compared with the prior art, the beneficial effects of the present application are that the present application is based on the monitoring unit to periodically collect the external hydro-meteorological data and internal structure response data of the cofferdam through the sensor group; the model construction unit is based on the finite element method to establish a multi-field coupling model, dynamically coupling the wave load, tidal level and seepage pressure field; the decision unit is based on the difference between the minimum safety factor and the preset safety factor to determine the minimum cofferdam top elevation; and the analysis unit is based on the minimum cofferdam top elevation input to the multi-field coupling model to acquire the maximum value of the water slope at the backwater slope out escape point within the third preset time length, based on the maximum value to determine the anti-seepage state, and based on the anti-seepage state to adjust the related parameters. The present application reduces the leakage rate of the earth-rock cofferdam through real-time monitoring, prediction and active control of the seepage risk of the cofferdam.

[0021] Further, the present application defines the specific implementation mechanism of the multi-field coupling model, through the closed-loop iteration of "boundary condition driving-seepage field analysis-stress field analysis-coupling feedback", the model can truly reflect how the dynamic load such as wave and tide affects the seepage field and structural stress inside the cofferdam, and how the soil deformation affects the seepage characteristics in return, thereby further improving the accuracy and reliability of the prediction, and further reducing the leakage rate of the earth-rock cofferdam.

[0022] Further, the present application determines the iterative algorithm of "the minimum cofferdam top elevation", through the automated process of "judgment-adjustment-iteration", the system can intelligently find an optimal solution that meets the preset safety standard and avoids excessive conservative design, which can further reduce the deviation, thereby further reducing the leakage rate of the earth-rock cofferdam.

[0023] Further, the present application determines whether to adjust the preset threshold based on the variance of the maximum value of the water slope at the backwater slope out escape point within the third preset time length at multiple historical moments, which can more accurately determine the reason for the unqualified anti-seepage state, so that the subsequent adjustment of the related parameters is more effective, thereby further reducing the leakage rate of the earth-rock cofferdam.

[0024] Further, the present application adjusts the preset threshold based on the ratio of the variance and the preset variance, can make the preset threshold more accurate adjustment, so as to more accurately determine the minimum cofferdam top elevation, and further reduce the seepage rate of the earth-rock cofferdam while ensuring the cost saving of the project.

[0025] Further, the present application determines whether to adjust the tolerance based on the integral of the time-water slope curve, can more accurately determine the reason for the unqualified seepage state, and more effectively adjust the related parameters based on the reason, thereby further reducing the seepage rate of the earth-rock cofferdam.

[0026] Further, the present application adjusts the tolerance based on the ratio of the integral and the preset integral, can make the setting of the tolerance more accurate, so that the feedback module in the multi-field coupling module is more effectively iterated, the model is more effectively fitted, and the seepage rate of the earth-rock cofferdam is further reduced.

[0027] Further, the present application determines whether to adjust the preset time length based on the average value of the absolute value of the difference between the displacement fields corresponding to each of the two consecutive iterations within the preset time length, can more accurately determine the reason for the unqualified seepage state, and more effectively adjust the related coefficients based on the accurate reason, thereby further reducing the seepage rate of the earth-rock cofferdam.

[0028] Further, the present application adjusts the preset time length based on the ratio of the average value and the preset average value, can make the feedback module more effectively iterated, so that the model result is more accurate, and the seepage rate of the earth-rock cofferdam is further reduced.

[0029] Further, the present application adjusts the period of the sensor group monitoring data group based on the number of times that the maximum value of the backwater slope out escape point hydraulic gradient is greater than the preset value within the plurality of preset time lengths, can make the model deduction result more accurate based on the more effective data obtained, thereby further reducing the seepage rate of the earth-rock cofferdam. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 It is a structural schematic diagram of the seepage control system for the earth-rock cofferdam of the embodiment of the present application.

[0031] Figure 2 It is a step flow chart of the seepage control method for the earth-rock cofferdam of the embodiment of the present application.

[0032] Figure 3 It is a step flow chart of the determination based on the comparison result of the maximum value of the backwater slope out escape point hydraulic gradient and the preset value within the third preset time length of the embodiment of the present application.

[0033] Figure 4 It is a step flow chart of the determination based on the seepage state after adjusting the preset threshold of the embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the objects and advantages of the present application clearer, the following further describes the present application with reference to examples; it should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0035] The preferred embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art will understand that the embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0036] It should be noted that, in the description of the present application, unless explicitly defined and limited, the terms "mounting", "connection", "linking" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral connection; it can be mechanical connection, or electrical connection; it can be direct connection, or indirect connection through intermediate medium, or internal connection of two elements. Those skilled in the art can understand the specific meaning of the above terms in the present application according to specific circumstances.

[0037] Please refer to Figure 1 Fig. 1 is a structural schematic diagram of a seepage control system for an earth-rock cofferdam according to an embodiment of the present application.

[0038] The system comprises a monitoring unit, a model construction unit, a decision unit and an analysis unit.

[0039] The monitoring unit is used to periodically monitor a data group based on a sensor group, which comprises a hydro-meteorological sensor group for collecting external environmental data of the cofferdam and a structure response sensor group for collecting internal state data of the cofferdam;

[0040] The model construction unit is connected with the monitoring unit, and is used to construct a multi-field coupling model based on a finite element method, wherein the multi-field coupling model dynamically couples and iterates wave load, tidal level and seepage pressure field in the data group within a first preset time length;

[0041] The decision unit is connected with the monitoring unit and the model construction unit respectively, and is used to calculate a difference between a minimum safety factor determined by inputting hydrological condition predicted after a second preset time length into the multi-field coupling model and a preset safety factor, and determine a minimum cofferdam top elevation based on a comparison result of the difference and a preset threshold value;

[0042] The analysis unit is connected with the decision unit, which is used to input the minimum cofferdam top elevation into the multi-field coupling model to obtain a maximum value of the hydraulic slope of the backwater slope escape point within a third preset time length, determine the anti-seepage state based on the maximum value, adjust the preset threshold based on the anti-seepage state, and adjust the first preset time length based on the anti-seepage state after the adjustment of the preset threshold.

[0043] Specifically, the monitoring unit includes wave meters, tide gauges, flow meters, rainfall monitoring stations and the like arranged inside and outside the cofferdam, for real-time collection of external environmental data, and includes pore water pressure gauges, soil pressure cells, strain gauges, inclinometers, displacement monitoring points and the like embedded in the cofferdam and steel sheet piles, for real-time monitoring of the internal state of the cofferdam such as the phreatic line, deformation and stress.

[0044] Specifically, the model construction unit adopts a third-generation wave model such as SWAN or Boussinesq equation, takes the measured wind field as input, calculates the wave pressure distribution time curve of the cofferdam water surface, and solves the modified seepage control equation based on the finite element method, that is, where K is the unsaturated permeability coefficient tensor, which is a function of the matrix suction and the effective stress , so as to introduce the influence of the stress state on the permeability, represents the water capacity, and the position water head reflects the influence of gravity on seepage. The boundary conditions are: the water surface is a pressure water head boundary varying with time, which is determined by the tide level and the wave pressure; the backwater surface is a flow boundary or a known water head boundary.

[0045] The seepage volume force calculated by the seepage calculation and the wave load are applied as body force loads to the cofferdam for stress-deformation analysis, and the Mohr-Coulomb elastic-plastic constitutive model is used to calculate the displacement field U and the stress field . The calculated volume strain updates the porosity and permeability coefficient of the soil, and is fed back to the seepage field analysis module. In one time step, the seepage-stress iterative calculation is carried out until the result converges, and then the next time step is entered to realize full coupling analysis.

[0046] Specifically, the decision unit initially drafts an initial cofferdam top elevation, and drives a multi-field coupling model to perform time-history analysis on the safety of the cofferdam under various possible hydrological combinations in the future, and calculates a key indicator: the minimum safety factor, i.e., the minimum anti-sliding stability safety factor Fs_min of the slope, if Fs_min is less than a preset safety factor, the initial cofferdam top elevation is automatically increased, if Fs_min is much greater than the preset safety factor, the initial cofferdam top elevation is appropriately reduced, and the multi-field coupling model is driven again based on the adjusted initial cofferdam top elevation, the iteration is stopped when the difference between Fs_min and the preset safety factor is controlled within a preset range, the preset range is greater than zero and less than or equal to a preset threshold, and the cofferdam top elevation after stopping iteration is determined as the minimum cofferdam top elevation.

[0047] Please refer to Figure 2 Fig. 1 is a step flow chart of the method for seepage control of the earth-rock cofferdam according to an embodiment of the present application.

[0048] The steps of the method for seepage control of the earth-rock cofferdam according to the present application include:

[0049] S1, periodically monitoring a data set by a sensor set in a monitoring unit, wherein the sensor set includes a hydro-meteorological sensor set for collecting external environmental data of the cofferdam and a structure response sensor set for collecting internal state data of the cofferdam;

[0050] S2, constructing a multi-field coupling model based on a finite element method by a model construction unit connected to the monitoring unit, wherein the multi-field coupling model dynamically couples and iterates the wave load, the tidal level and the seepage pressure field in the data set within a first preset time length;

[0051] S3, calculating, by a decision unit connected to the monitoring unit and the model construction unit respectively, a difference between a minimum safety factor determined based on the data set and the hydrological condition input into the multi-field coupling model after a second preset time length and a preset safety factor, and determining a minimum cofferdam top elevation based on a comparison result of the difference and a preset threshold;

[0052] S4, inputting, by an analysis unit connected to the decision unit, the minimum cofferdam top elevation into the multi-field coupling model to obtain a maximum value of the hydraulic slope of the back-slope outflow point within a third preset time length, determining a seepage state based on the maximum value, adjusting the preset threshold based on the seepage state, and adjusting the first preset time length based on the seepage state after adjusting the preset threshold.

[0053] Please refer to Figure 3 Fig. 4 is a step flow chart of the determination step based on the comparison result of the maximum value of the hydraulic slope of the back-slope outflow point within the third preset time length and the preset value according to an embodiment of the present application.

[0054] Specifically, taking the seepage control of the earth-rock cofferdam as an example, and based on the physical performance limits of the seepage prevention materials such as the clay core, the physical performance limits of the geomembrane, and the structural fault tolerance requirements of the cofferdam under actual wave, tidal load, and combined with historical seepage monitoring, critical hydraulic slope of the phreatic line evolution, piping occurrence, and other historical data obtained during the statistical analysis of the risk disposal process, the subsequent numerical setting of the preset or critical parameters is carried out.

[0055] Specifically, taking the cohesive soil as an example, the preset value L0 of the maximum value of the hydraulic slope of the outflow point of the landward slope in the third preset time period is 1.5, and the comparison process based on the maximum value L of the hydraulic slope of the outflow point of the landward slope in the third preset time period and the preset value L0 is as follows:

[0056] If the maximum value L of the hydraulic slope of the outflow point of the landward slope in the third preset time period is less than or equal to the preset value L0, it is determined that the seepage prevention state is qualified.

[0057] If the maximum value L of the hydraulic slope of the outflow point of the landward slope in the third preset time period is greater than the preset value L0, it is determined that the seepage prevention state is unqualified.

[0058] Specifically, in the case where the seepage prevention state is unqualified, the variance of the maximum value of the hydraulic slope of the outflow point of the landward slope in the third preset time period is calculated; if the variance is less than the preset variance, it indicates that the minimum cofferdam top elevation determined by the decision unit has a problem, thereby causing the maximum value of the hydraulic slope of the outflow point of the landward slope to be greater than the preset value, and then the preset threshold value is adjusted based on the ratio of the variance to the preset variance, wherein the preset ratio P0 of the variance to the preset variance is 0.62, and the comparison process based on the ratio P of the variance to the preset variance and the preset ratio P0 is as follows:

[0059] If the ratio P of the variance to the preset variance is less than or equal to the preset ratio P0, the preset threshold value is adjusted to 0.83 times the original preset threshold value.

[0060] If the ratio P of the variance to the preset variance is greater than the preset ratio P0, the preset threshold value is adjusted to 0.91 times the original preset threshold value.

[0061] Specifically, the above multiple values are determined according to the corresponding values with the best effect in the historical experience and experimental data analysis results.

[0062] Please refer to Figure 4 , which is a step flow chart for determining the seepage prevention state based on the adjusted preset threshold value according to an embodiment of the present application.

[0063] Specifically, the anti-seepage state after adjusting the preset threshold value is determined, if the anti-seepage state is unqualified, the preset threshold value is repeatedly adjusted at least once, until the adjustment times is less than the preset times and the anti-seepage state is qualified or the adjustment times is equal to the preset times, and the adjustment is stopped; if the anti-seepage state is unqualified after the adjustment is stopped, a time-hydraulic gradient curve is drawn based on the hydraulic gradient of the backwater slope out escape point at multiple moments in the third preset time period, an integral of the curve is calculated, if the integral is greater than a preset integral, it indicates that the hydraulic gradient is large for a long time, and the reason is that the feedback module in the multi-field coupling module has a problem, that is, the iteration is insufficient, resulting in that the model is not fitted, so that the result is inaccurate, and then the tolerance is adjusted based on the ratio of the integral to the preset integral, wherein the preset ratio Q0 of the integral to the preset integral is 1.4, and the comparison process of the ratio Q of the integral to the preset integral to the preset ratio Q0 is specifically as follows:

[0064] If the ratio Q of the integral to the preset integral is less than or equal to the preset ratio Q0, the tolerance is adjusted to 0.93 times of the original tolerance.

[0065] If the ratio Q of the integral to the preset integral is greater than the preset ratio Q0, the tolerance is adjusted to 0.76 times of the original tolerance.

[0066] Specifically, the above multiple values are determined according to the corresponding values with the best effect in the historical experience and experimental data analysis results.

[0067] Specifically, the anti-seepage state after adjusting the adjustment tolerance is determined, if the anti-seepage state is unqualified, the difference value of the displacement field corresponding to each continuous two iterations in the first preset time period is obtained, the average value of the absolute values of the plurality of difference values is calculated, if the average value is greater than a preset average value, it indicates that the iteration of the feedback module is still insufficient, so that the model is not fitted, so that the model result is inaccurate, and then the first preset time period is adjusted based on the ratio of the average value to the preset average value, wherein the preset ratio R0 of the average value to the preset average value is 1.89, and the comparison process of the ratio R of the average value to the preset average value to the preset ratio R0 is specifically as follows:

[0068] If the ratio R of the average value to the preset average value is less than or equal to the preset ratio R0, the first preset time period is adjusted to 1.7 times of the original first preset time period, and the adjusted first preset time period is all rounded up.

[0069] If the ratio R of the average value to the preset average value is greater than the preset ratio R0, the first preset time period is adjusted to 2.5 times of the original first preset time period, and the adjusted first preset time period is all rounded up.

[0070] Specifically, the above multiple values are determined according to the corresponding values with the best effect in the historical experience and experimental data analysis results.

[0071] Specifically, the anti-seepage state after the first preset time length is re-determined, if the anti-seepage state is unqualified, the number of times that the maximum value of the water slope of the backwater slope escape point in the third preset time length is greater than the preset value is obtained, if the number of times is greater than the preset number of times, it means that if the predicted value deviates from the subsequent measured value seriously in a plurality of continuous periods, especially when the external environment changes rapidly, it means that the "old data" based on the model has been unable to effectively deduce the "new state", the monitoring period has not kept up with the speed of environmental change, then the period of the sensor group monitoring the data group is adjusted based on the difference between the number of times and the preset number of times, wherein the preset difference T0 between the number of times and the preset number of times is 3, and the comparison process of the difference T between the number of times and the preset number of times and the preset difference T0 is as follows:

[0072] If the difference T between the number of times and the preset number of times is less than or equal to the preset difference T0, the period of the sensor group monitoring the data group is adjusted to 0.87 times the original period, and the adjusted period is all rounded up;

[0073] If the difference T between the number of times and the preset number of times is greater than the preset difference T0, the period of the sensor group monitoring the data group is adjusted to 0.64 times the original period, and the adjusted period is all rounded up.

[0074] Specifically, the above multiple values are determined according to the corresponding values with the best effect in the historical experience and experimental data analysis results.

[0075] So far, the technical scheme of the present application has been described in conjunction with the preferred embodiments shown in the drawings, but those skilled in the art will readily understand that the protection scope of the present application is obviously not limited to these specific embodiments. Those skilled in the art can make equivalent changes or replacements to related technical features without departing from the principles of the present application, and the technical scheme after the changes or replacements will fall within the protection scope of the present application.

[0076] The above description is only the preferred embodiments of the present application and is not intended to limit the present application; for those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A seepage prevention control system for earth-rock cofferdams, characterized in that, include: The monitoring unit is used to periodically monitor the data set based on the sensor set, including the hydro-meteorological sensor set for collecting external environmental data of the cofferdam and the structural response sensor set for collecting internal state data of the cofferdam. A model building unit, which is connected to the monitoring unit, is used to build a multi-field coupling model based on the finite element method. The multi-field coupling model dynamically couples and iterates the wave load, tidal level and seepage pressure field in the data set within a first preset time period. The decision-making unit, which is connected to the monitoring unit and the model building unit respectively, is used to calculate the difference between the minimum safety factor determined by inputting the hydrological conditions predicted after the data set and the second preset time into the multi-field coupling model and the preset safety factor, and to determine the minimum cofferdam crest elevation based on the comparison result of the difference and the preset threshold. An analysis unit, connected to the decision unit, is used to input the minimum cofferdam crest elevation into the multi-field coupling model to obtain the maximum value of the hydraulic gradient at the back slope outlet point within a third preset time period, determine the seepage prevention status based on the maximum value, and adjust the preset threshold based on the seepage prevention status, and adjust the first preset time period based on the seepage prevention status after adjusting the preset threshold. The model building unit also includes: The boundary condition driving module is used to receive wave load time series data and tidal level difference time series data, and convert the wave load time series data and the tidal level difference time series data into dynamic boundary conditions for seepage field calculation. The seepage field analysis module, which is connected to the boundary condition driving module, is used to calculate the seepage control equation based on the dynamic boundary conditions in order to determine the pore water pressure distribution and the location of the phreatic line inside the cofferdam. The stress field analysis module, which is connected to the seepage field analysis module, is used to convert the pore water pressure distribution into seepage volume forces acting on the soil skeleton and the external environmental data to determine the displacement field and stress field of the cofferdam. A coupling module, which is connected to the seepage field analysis module and the stress field analysis module respectively, is used to calculate the volumetric strain of each finite element based on the stress field and the displacement field, and to periodically update the porosity of the corresponding finite element based on the volumetric strain of each finite element, and to calculate the corresponding permeability coefficient. The feedback module is connected to the seepage field analysis module and the coupling module respectively, and is used to feed back the permeability coefficient to the seepage field analysis module. The coupling module is iterated at least once every time step within the first preset time period until the difference between the displacement fields corresponding to two consecutive iterations is less than the tolerance or the total iteration time is equal to the first preset time period and the iteration stops.

2. The seepage prevention control system for earth-rock cofferdams according to claim 1, characterized in that, The decision-making unit also includes: The judgment module is used to run the multi-field coupled model based on the set initial cofferdam crest elevation to determine the minimum safety factor; An adjustment module, which is connected to the judgment module, is used to adjust the initial cofferdam crest elevation based on the comparison result between the minimum safety factor and the preset safety factor. An iteration module, which is connected to the judgment module and the adjustment module respectively, executes the judgment module and the adjustment module at least once based on the adjusted initial cofferdam crest elevation, until the difference between the minimum safety factor determined during iteration and the preset safety factor is greater than zero and less than or equal to the preset threshold, and stops the iteration, and determines the cofferdam crest elevation determined after the iteration stops as the minimum cofferdam crest elevation.

3. The seepage prevention control system for earth-rock cofferdams according to claim 2, characterized in that, The analysis unit is also used to calculate the variance of the maximum value of the hydraulic gradient at the back slope outlet point within the third preset time period when it is determined that the seepage prevention status is unqualified. The analysis unit is also used to adjust the preset threshold based on the ratio of the variance to the preset variance when the variance is less than the preset variance. If the maximum value of the hydraulic gradient at the outlet point of the back slope within the third preset time period is greater than the preset value, the seepage prevention status is deemed unqualified.

4. The seepage prevention control system for earth-rock cofferdams according to claim 3, characterized in that, The analysis unit is also used to reduce the preset threshold based on the ratio of the variance to the preset variance, and the reduction of the preset threshold is inversely proportional to the ratio.

5. The seepage prevention control system for earth-rock cofferdams according to claim 4, characterized in that, The analysis unit is also used to repeatedly adjust the preset threshold at least once if the seepage prevention status is not qualified after adjusting the preset threshold, until the adjustment is stopped when the number of adjustments is less than the preset number and the seepage prevention status is qualified or the number of adjustments is equal to the preset number. The analysis unit is also used to plot a time-hydraulic gradient curve based on the hydraulic gradient of the back slope outlet point at multiple times within the third preset time period when the seepage prevention state is unqualified after the adjustment is stopped. The analysis unit is also used to calculate the integral of the curve and, if the integral is greater than a preset integral, to adjust the tolerance based on the ratio of the integral to the preset integral.

6. The seepage prevention control system for earth-rock cofferdams according to claim 5, characterized in that, The analysis unit is also used to reduce the tolerance based on the ratio of the integral to a preset integral, and the reduction in tolerance is proportional to the ratio.

7. The seepage prevention control system for earth-rock cofferdams according to claim 6, characterized in that, The analysis unit is also used to obtain the difference in the displacement field corresponding to each consecutive two iterations within the first preset time period when the seepage prevention state is unqualified after adjusting the tolerance. The analysis unit is also used to calculate the average of the absolute values ​​of multiple differences and, if the average value is greater than a preset average value, to adjust the first preset duration based on the ratio of the average value to the preset average value.

8. The seepage prevention control system for earth-rock cofferdams according to claim 7, characterized in that, The analysis unit is also used to increase the first preset duration based on the ratio of the average value to the preset average value, and the increase in the first preset duration is proportional to the ratio.

9. The seepage prevention control system for earth-rock cofferdams according to claim 8, characterized in that, The analysis unit is also used to obtain the number of times the maximum value of the hydraulic gradient at the back slope outlet point within the third preset time period is greater than the preset value when the seepage prevention status is unqualified after adjusting the first preset time period. The analysis unit is also used to reduce the period of the sensor group monitoring the data group based on the difference between the number of times and the preset number of times when the number of times exceeds the preset number of times, and the reduction in period is proportional to the difference.

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