Method for analyzing soil pressure on high toe wall in water storage period of dam body structure

Abstract

The invention discloses a method for analyzing the soil pressure on a high toe wall in the water storage period of a dam body structure, belongs to the technical field of dam body engineering, and can solve the problem that in the prior art, a soil pressure calculation method in the current specification is directly applied, and the difference between the soil pressure calculation method and the soil pressure distribution condition calculated by a finite element is large. The method comprises the steps that S1, the completion period soil pressure on the interface of the high toe wall and the rock-fill dam is determined; s2, the ratio of the water storage depth to the rock-fill dam height serves as an independent variable, the ratio of the soil pressure increase value on the interface of the high toe wall and the rock-fill dam in the water storage period to the soil pressure in the completion period serves as a dependent variable, and an S-shaped growth curve equation is constructed; and S3, empirical parameters in the S-shaped growth curve equation are determined, and according to the S-shaped growth curve equation and the empirical parameters thereof, the water storage period soil pressure on the interface of the high toe wall and the rock-fill dam is determined. The method is used for calculating the soil pressure on the high toe wall in the water storage period of the dam body structure.

Description

Technical Field

[0001] The invention relates to an analysis method for soil pressure on a high toe wall of a dam structure during water storage period, belonging to the technical field of dam engineering. Background Art

[0002] In recent years, a large number of domestic projects have applied the concrete high toe wall technology to the panel rockfill dam project to transform the unfavorable terrain and geological conditions, so that the concrete panel is connected with the high toe wall to form a complete anti-seepage system. The shape and structural stress conditions of the high toe wall are relatively complex. At the same time, as a component of the toe plate anti-seepage body of the concrete panel rockfill dam, its safety and stability are extremely important to the normal operation of the panel rockfill dam.

[0003] Most high toe walls are submerged and are subject to the combined effects of rockfill pressure, water pressure and other loads. Their working conditions are more complex than those of conventional retaining walls. In the prior art, the rockfill pressure at the interface between the high toe wall and the rockfill body is often calculated using the Coulomb earth pressure theory. Regardless of whether it is active earth pressure or passive earth pressure, this method assumes that the earth pressure changes in a triangular distribution pattern along the back and height of the wall. However, the surface load of the submerged high toe wall is distributed vertically on the slope of the dam body. Directly applying the calculation method in the current specification is quite different from the earth pressure distribution calculated by finite element method. Summary of the invention

[0004] The present invention provides an analysis method for the earth pressure on the high toe wall of a dam structure during the water storage period, which can solve the problem that the earth pressure calculation method in the current specification directly applied in the prior art is quite different from the earth pressure distribution calculated by finite element method.

[0005] The present invention provides a method for analyzing earth pressure on a high toe wall of a dam structure during a water storage period, the method comprising: S1. Determine the earth pressure at the interface between the high toe wall and the rockfill dam at the completion period; S2. Taking the ratio of water storage depth to the height of the rockfill dam as the independent variable and the ratio of the earth pressure increase at the interface between the high toe wall and the rockfill dam during the water storage period and the earth pressure at the completion period as the dependent variable, an S-shaped growth curve equation is constructed; S3. Determine the empirical parameters in the S-type growth curve equation, and determine the soil pressure on the interface between the high toe wall and the rockfill dam during the water storage period based on the S-type growth curve equation and its empirical parameters.

[0006] Optionally, the determining of the empirical parameters in the S-shaped growth curve equation in S3 specifically includes: Determining a first group of influencing factors of the empirical parameters; A fitting formula for the empirical parameters is determined according to the first influencing factor group.

[0007] Optionally, the first influencing factor group for determining the empirical parameter is specifically: The first influencing factor group of the empirical parameters is determined according to an orthogonal test method.

[0008] Optionally, the fitting formula for determining the empirical parameter according to the first influencing factor group is specifically: According to the first influencing factor group, a multiple linear regression method is used to perform linear fitting on the empirical parameters to obtain a fitting formula for the empirical parameters.

[0009] Optionally, the empirical parameters include the curve vertex value , Growth rate and the midpoint of the curve .

[0010] Optionally, the first influencing factor group includes the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the height of the high toe wall and the height of the rockfill dam.

[0011] Optionally, the S1 specifically includes: The rockfill dam is divided into a first rockfill body located below the horizontal plane and close to the high toe wall, a second rockfill body located directly above the first rockfill body, a third rockfill body located above the horizontal plane and close to the second rockfill body, and a fourth rockfill body located directly below the third rockfill body by using a plumb plane passing through the bottom of the high toe wall and a horizontal plane passing through the top of the high toe wall; The gravity of the first rockfill body and the second rockfill body, as well as the uniformly distributed load applied by the third rockfill body on the top surface of the fourth rockfill body and the earth pressure coefficient of the dam body are determined, and the earth pressure at the completion period on the interface between the high toe wall and the rockfill dam is determined according to the gravity of the first rockfill body and the second rockfill body, the uniformly distributed load and the earth pressure coefficient.

[0012] Optionally, the determining of the uniformly distributed load applied by the third rockfill body on the top surface of the fourth rockfill body is specifically: The gravity of the third rockfill body is determined, and the gravity of the third rockfill body is converted into a uniformly distributed load applied to the top surface of the fourth rockfill body.

[0013] Optionally, the determination of the earth pressure coefficient of the dam body is specifically as follows: Determine a second influencing factor group of the earth pressure coefficient according to an orthogonal test method; According to the second influencing factor group, a linear fitting is performed on the earth pressure coefficient using a multiple linear regression method to obtain a fitting formula for the earth pressure coefficient.

[0014] Optionally, the second influencing factor group includes the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the height of the high toe wall and the height of the rockfill dam.

[0015] The beneficial effects that the present invention can produce include: The method for analyzing the earth pressure on the high toe wall of the dam structure during the water storage period provided by the present invention takes the ratio of the water storage depth to the dam height of the rockfill dam as the independent variable, takes the ratio of the earth pressure increase value on the interface between the high toe wall and the rockfill dam during the water storage period and the earth pressure during the completion period as the dependent variable, constructs an S-type growth curve equation, and uses the S-type growth curve equation to determine the earth pressure on the interface between the high toe wall and the rockfill dam during the water storage period. The method has high fitting accuracy, and the change in the growth rate of the curve is consistent with the change trend of the finite element calculation result. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flow chart of a method for analyzing earth pressure on a high toe wall of a dam structure during water storage provided by an embodiment of the present invention; Figure 2 A schematic diagram of soil pressure variation with increasing water storage depth provided by an embodiment of the present invention; Figure 3 A schematic diagram of soil pressure fitting with increasing water storage depth provided by an embodiment of the present invention; Figure 4 The various factors provided in the embodiment of the present invention have an effect on the earth pressure coefficient Main effects plots of the effects; Figure 5 The factors provided in the embodiment of the present invention are empirical parameters Main effects plots of the effects; Figure 6 The factors provided in the embodiment of the present invention are empirical parameters Main effects plots of the effects; Figure 7 The factors provided in the embodiment of the present invention are empirical parameters Main effects plots of the effects; Figure 8 A schematic diagram of a high toe wall and a rockfill dam structure provided by an embodiment of the present invention; Fig. 9 A schematic diagram for comparing the calculated value of soil pressure during the water storage period provided by an embodiment of the present invention with the finite element calculation result. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0018] The embodiment of the present invention provides a method for analyzing the earth pressure on the high toe wall of a dam structure during the water storage period. Figure 1 As shown, the method includes: S1. Determine the earth pressure at the interface between the high toe wall and the rockfill dam at the completion stage.

[0019] The embodiment of the present invention does not limit the method for determining the soil pressure during the completion period. For example, it can be obtained by using a finite element simulation method or by using a theoretical formula calculation method.

[0020] S2. Taking the ratio of water storage depth to the height of the rockfill dam as the independent variable and the ratio of the increase in earth pressure at the interface between the high toe wall and the rockfill dam during the water storage period and the earth pressure at the completion period as the dependent variable, an S-shaped growth curve equation is constructed.

[0021] Among them, the expression of the S-shaped growth curve equation is as follows: ; In the formula, the independent variable is , which represents the ratio of water storage depth to the height of the rockfill dam. The dependent variable is , is the ratio of the earth pressure increase caused by water storage to the earth pressure at the completion period; is the earth pressure at the interface between the high toe wall and the rockfill dam during the water storage period after water storage; is the earth pressure at the interface between the high toe wall and the rockfill dam after completion; is the water storage depth; The rockfill dam is high; is the empirical parameter in the S-shaped growth curve equation.

[0022] S3. Determine the empirical parameters in the S-type growth curve equation, and determine the earth pressure at the interface between the high toe wall and the rockfill dam during the water storage period based on the S-type growth curve equation and its empirical parameters.

[0023] Among them, the empirical parameters in the S-shaped growth curve equation are determined, including: Firstly, the first influencing factor group of the empirical parameters is determined; specifically, the first influencing factor group of the empirical parameters is determined according to an orthogonal test method.

[0024] Then, the fitting formula of the empirical parameters is determined according to the first influencing factor group; specifically, according to the first influencing factor group, a multivariate linear regression method is used to perform linear fitting on the empirical parameters to obtain the fitting formula of the empirical parameters.

[0025] The above empirical parameters include the curve vertex value , Growth rate and the midpoint of the curve .

[0026] The first influencing factor group includes the upstream slope ratio of the rockfill dam , Downstream slope ratio of high toe wall , High toe wall height and rockfill dam height .

[0027] The orthogonal test method and multiple linear regression method were used to obtain The formula for determining empirical parameters is: When the rockfill material is soft rock, Calculate according to the following formula respectively.

[0028] ; ; .

[0029] When the rockfill material is limestone or gravel, Calculate according to the following formula respectively.

[0030] ; ; .

[0031] After determining the empirical parameters After taking the value of Substituting the value of into the S-shaped growth curve equation, the soil pressure during the water storage period can be obtained: .

[0032] When the theoretical formula is used to calculate the earth pressure at completion When S1 is used, it specifically includes: (1) The vertical plane passing through the bottom of the high toe wall and the horizontal plane passing through the top of the high toe wall are used to divide the rockfill dam into a first rockfill body located below the horizontal plane and close to the high toe wall, a second rockfill body located directly above the first rockfill body, a third rockfill body located above the horizontal plane and close to the second rockfill body, and a fourth rockfill body located directly below the third rockfill body.

[0033] refer to Figure 8 As shown in the figure, ABGF is the high toe wall and AHIJB is the rockfill dam. An imaginary plumb plane BD is made along the bottom of the high toe wall, and an imaginary horizontal plane AE is made along the top of the high toe wall to divide the rockfill dam fill behind the wall into four parts: the first rockfill body I below the AE surface and to the left of the BD surface, the second rockfill body II above the AE surface and to the left of the BD surface, the third rockfill body III above the AE surface and to the right of the BD surface, and the fourth rockfill body IV below the AE surface and to the right of the BD surface.

[0034] (2) Determine the gravity of the first and second rock piles, the uniformly distributed load exerted by the third rock pile on the top surface of the fourth rock pile, and the earth pressure coefficient of the dam body.

[0035] The following formula is used to determine the gravity of the first pile of rocks.

[0036] ; In the formula, is the gravity of the first pile of rocks; is the weight of the rock pile; is the slope ratio of the downstream face of the high toe wall; is the high toe wall height.

[0037] The following formula is used to determine the gravity of the second pile of rocks.

[0038] ; Where: is the gravity of the second pile of rocks; is the weight of the rock pile; is the slope ratio of the downstream face of the high toe wall; is the upstream slope ratio of the rockfill dam; is the high toe wall height.

[0039] The uniformly distributed load applied by the third rockpile to the top surface of the fourth rockpile is determined, specifically: the gravity of the third rockpile is determined, and the gravity of the third rockpile is converted into the uniformly distributed load applied to the top surface of the fourth rockpile.

[0040] The earth pressure coefficient of the dam body is determined by: firstly determining the second influencing factor group of the earth pressure coefficient according to the orthogonal test method; then according to the second influencing factor group, the earth pressure coefficient is linearly fitted by the multivariate linear regression method to obtain the fitting formula of the earth pressure coefficient.

[0041] The second influencing factor group includes the upstream slope ratio of the rockfill dam , Downstream slope ratio of high toe wall , High toe wall height and rockfill dam height .

[0042] For the earth pressure coefficient For example, the orthogonal test method and the multiple linear regression method can be used to obtain the determined formula.

[0043] When the rockfill material is soft rock, The values ​​are as follows: ; When the rockfill material is gravel or limestone, The values ​​are shown in the following formula: ; In the formula, is the earth pressure coefficient, is the upstream slope ratio of the rockfill dam; is the high toe wall height; The height of the rockfill dam is is the slope ratio of the downstream face of the high toe wall.

[0044] (3) The earth pressure at the interface between the high toe wall and the rockfill dam at the completion stage is determined based on the gravity, uniformly distributed load and earth pressure coefficient of the first and second rockfill bodies.

[0045] The earth pressure at completion is determined using the following formula.

[0046]

[0047] Where: is the earth pressure at completion; is the gravity of the first pile of rocks; is the gravity of the second pile of rocks; is the weight of the rock pile; is the high toe wall height; is the uniformly distributed load applied to the top surface of the fourth rock pile, is the earth pressure coefficient.

[0048] The derivation process of the calculation formula for the earth pressure on the interface between the high toe wall and the rockfill dam during the water storage period is described in detail below.

[0049] Figure 2 This is a graph of soil pressure changes with increasing water storage elevation based on statistical analysis of monitoring data for a certain project. The top elevation of the high toe wall is 1510.00m. Figure 2 It can be seen that there is no clear functional relationship between the normal force at the interface between the high toe wall and the rockfill and the reservoir water pressure, but the characterization law conforms to the S-type growth curve equation, so the S-type growth curve equation is used to fit the normal force of the interface.

[0050] ; In the formula, the independent variable is , which represents the ratio of water storage depth to the height of the rockfill dam. The dependent variable is , is the ratio of the earth pressure increase caused by water storage to the earth pressure at the completion period; is the earth pressure at the interface between the high toe wall and the rockfill dam during the water storage period after water storage; is the earth pressure at the interface between the high toe wall and the rockfill dam after completion; is the water storage depth; The rockfill dam is high; is the empirical parameter in the S-shaped growth curve equation.

[0051] After the water is stored by the project, When the earth pressure formula is as follows, the fitting curve is as follows Figure 3 The fitting curve is very close to the finite element calculation result, and the correlation coefficient The fitting accuracy is about 0.9978, and the change of the growth rate of the curve is consistent with the change trend of the finite element calculation results. The fitting formula simulates the change and development of the earth pressure at the interface between the high toe wall and the rockfill after water storage, and the effect is good.

[0052] .

[0053] Based on the derivation of the above formula, accurate determination The value of is the key to calculating the earth pressure behind the high toe wall during the water storage period.

[0054] for The value of is first determined by the orthogonal test method.

[0055] The orthogonal array has the construction principles of "balanced dispersion" and "neat comparability". The number of experiments designed according to this method is small and can reflect the changing laws of objective things. Orthogonal array design orthogonal experiment. Orthogonal experiment is determined as follows: Each factor replaces the corresponding design parameter value in the orthogonal table according to its different levels, which is the corresponding orthogonal test table. According to the values ​​of each factor in each test scheme, calculations are performed based on the established finite element model, and the soil pressure behind the wall is obtained by integral calculation, and then the pressure under different test conditions is calculated. The calculation results are shown in Table 1.

[0056] Table 1 Orthogonal test scheme and calculation results

[0057] The differences between different levels of a factor are called the main effects of the factor. Figure 4 The analysis shows that the three factors The main effects of increase, gradually decreases, and and There is a good linear negative correlation between increase, Gradually increases, there is a good linear positive correlation between the two; increase, Gradually increase, and and There is a good linear positive correlation between them.

[0058] from Figure 5 , Figure 6 , Figure 7 The analysis shows that the three factors The main effects of increase, and Gradually increasing, gradually decreases; increase, Gradually decrease, gradually increase; increase, and Gradually increasing, Gradually decrease. Three factors and The three indicators can be approximately considered to have a linear relationship.

[0059] Based on the above, multiple linear regression method was used for further analysis. Figures 4 to 7 The regular characteristics show that the upstream slope ratio of the rockfill dam , the ratio of the high toe wall height to the rockfill dam height , the downstream slope ratio of the high toe wall These three factors work together to , assuming that there is no mutual influence between the three variables, the function forms are set as: ; In the formula, for Any one of the following; A is the upstream slope ratio of the rockfill dam ; B is the ratio of the high toe wall height to the rockfill dam height ; C is the slope ratio of the downstream surface of the high toe wall ; is the corresponding coefficient; is a constant term.

[0060] The 16 sets of data in the orthogonal test table are linearly fitted, and the upstream slope ratio of the rockfill dam is established according to the principle of least squares method. , Ratio of high toe wall height to rockfill dam height , Downstream slope ratio of high toe wall These three parameters are The computational model.

[0061] When the dam material is gravel or limestone, the fitting expressions are as follows: ; ; ; .

[0062] When the dam material is soft rock, the fitting expressions are as follows: ; ; ; .

[0063] The following is a comparison between the observation data of the monitoring prototype and the finite element simulation results of a certain project inlaid concrete face rockfill dam and the calculation results of the above theoretical formula.

[0064] The filling material of the dam body is basically limestone, and the upstream slope of the rockfill dam is , the ratio of the high toe wall height to the rockfill dam height , the downstream slope ratio of the high toe wall According to the formula proposed by the present invention, . It is calculated using the following formula.

[0065] .

[0066] After water storage, the ratio of the soil pressure increase caused by water storage to the soil pressure at the completion period is calculated using the S-shaped growth curve equation. The formula proposed in the present invention can be used to calculate: , , These three empirical parameters are calculated using the following formula.

[0067] ; ; .

[0068] Substituting into the S-shaped growth curve equation, the soil pressure on the back of the high toe wall during the water storage period is obtained. Fig. 9 As shown, no matter it is the dead water level or the normal water level, the absolute error between the calculated value of the theoretical formula and the calculated value of the finite element method is very small. It can be seen that the theoretical formula proposed in the present invention simulates the change and development of the earth pressure at the interface between the high toe wall and the rockfill body during the water storage period well, and has high accuracy.

[0069] The method for analyzing the earth pressure on the high toe wall of the dam structure during the water storage period provided by the present invention takes the ratio of the water storage depth to the dam height of the rockfill dam as the independent variable, takes the ratio of the earth pressure increase value on the interface between the high toe wall and the rockfill dam during the water storage period and the earth pressure during the completion period as the dependent variable, constructs an S-type growth curve equation, and uses the S-type growth curve equation to determine the earth pressure on the interface between the high toe wall and the rockfill dam during the water storage period. The method has high fitting accuracy, and the change in the growth rate of the curve is consistent with the change trend of the finite element calculation result.

[0070] The calculation idea of ​​soil pressure during the water storage period determined by the present invention is proposed for the first time, has clear physical meaning, and provides guarantee for the safety of high toe wall engineering of concrete face rockfill dam.

[0071] The above are only a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application is disclosed as above with preferred embodiments, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A method for analyzing earth pressure on the high toe wall of a dam structure during water storage, characterized in that: The method comprises: S1. Determine the earth pressure at the interface between the high toe wall and the rockfill dam at the completion period; S2. Taking the ratio of water storage depth to the height of the rockfill dam as the independent variable and the ratio of the earth pressure increase at the interface between the high toe wall and the rockfill dam during the water storage period and the earth pressure at the completion period as the dependent variable, an S-shaped growth curve equation is constructed; S3. Determine the empirical parameters in the S-type growth curve equation, and determine the soil pressure on the interface between the high toe wall and the rockfill dam during the water storage period based on the S-type growth curve equation and its empirical parameters.

2. The method according to claim 1, characterized in that Determining the empirical parameters in the S-shaped growth curve equation in S3 specifically includes: Determining a first group of influencing factors of the empirical parameters; A fitting formula for the empirical parameters is determined according to the first influencing factor group.

3. The method according to claim 2, characterized in that The first group of influencing factors for determining the empirical parameters is specifically: The first influencing factor group of the empirical parameters is determined according to an orthogonal test method.

4. The method according to claim 2, characterized in that: The fitting formula for determining the empirical parameters according to the first influencing factor group is specifically: According to the first influencing factor group, a multiple linear regression method is used to perform linear fitting on the empirical parameters to obtain a fitting formula for the empirical parameters.

5. The method according to claim 1, characterized in that The empirical parameters include the curve vertex value , Growth rate and the midpoint of the curve .

6. The method according to claim 2, characterized in that The first influencing factor group includes the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the height of the high toe wall and the height of the rockfill dam.

7. The method according to claim 1, characterized in that The S1 specifically includes: The rockfill dam is divided into a first rockfill body located below the horizontal plane and close to the high toe wall, a second rockfill body located directly above the first rockfill body, a third rockfill body located above the horizontal plane and close to the second rockfill body, and a fourth rockfill body located directly below the third rockfill body by using a plumb plane passing through the bottom of the high toe wall and a horizontal plane passing through the top of the high toe wall; The gravity of the first rockfill body and the second rockfill body, as well as the uniformly distributed load applied by the third rockfill body on the top surface of the fourth rockfill body and the earth pressure coefficient of the dam body are determined, and the earth pressure at the completion period on the interface between the high toe wall and the rockfill dam is determined according to the gravity of the first rockfill body and the second rockfill body, the uniformly distributed load and the earth pressure coefficient.

8. The method according to claim 7, characterized in that The determining of the uniformly distributed load applied by the third rockfill body to the top surface of the fourth rockfill body is specifically as follows: The gravity of the third rockfill body is determined, and the gravity of the third rockfill body is converted into a uniformly distributed load applied to the top surface of the fourth rockfill body.

9. The method according to claim 7, characterized in that: The determination of the earth pressure coefficient of the dam body is specifically as follows: Determine a second influencing factor group of the earth pressure coefficient according to an orthogonal test method; According to the second influencing factor group, a linear fitting is performed on the earth pressure coefficient using a multiple linear regression method to obtain a fitting formula for the earth pressure coefficient.

10. The method according to claim 9, characterized in that The second influencing factor group includes the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the height of the high toe wall and the height of the rockfill dam.

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