An analysis method of earth pressure on high toe wall during dam structure construction

Abstract

The present invention discloses an analysis method of soil pressure on a high toe wall during the construction period of a dam structure, which belongs to the technical field of dam engineering and can solve the problem that the soil pressure calculation method in the existing specification is directly applied in the prior art, and an erroneous result may be obtained. The method comprises: S1, 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 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; S2, determining the gravity of the first rockfill body and the second rockfill body, and the horizontal soil pressure on the interface between the first rockfill body and the fourth rockfill body; S3, determining the soil pressure on the high toe wall during the construction period according to the gravity of the first rockfill body and the second rockfill body, and the horizontal soil pressure. The present invention is used for calculating the soil pressure on the high toe wall.

Description

Technical Field

[0001] The invention relates to an analysis method for soil pressure on a high toe wall during the construction period of a dam structure, and belongs 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. The working conditions are more complicated than those of conventional retaining walls. The reasonable determination of rockfill pressure in stress calculation has a great influence on the reliability of the calculation results. At present, there is no clear provision for the calculation method of rockfill pressure in the specification, and only similar specifications can be referred to, such as the hydraulic retaining wall design specification. However, the form of surface load in most of these specifications is different from that of submerged high toe walls, and direct application may give wrong results. Summary of the invention

[0004] The invention provides an analysis method for earth pressure on a high toe wall during the construction period of a dam structure, which can solve the problem that a wrong result may be obtained by directly applying the earth pressure calculation method in the existing specification in the prior art.

[0005] The present invention provides a method for analyzing earth pressure on a high toe wall during the construction period of a dam structure, the method comprising:

[0006] S1, using a vertical plane passing through the bottom of the high toe wall and a horizontal plane passing through the top of the high toe wall 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;

[0007] S2, determining the gravity of the first rockfill body and the second rockfill body, and the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body;

[0008] S3. Determine the earth pressure on the high toe wall during the construction period according to the gravity of the first rock pile and the second rock pile, and the horizontal earth pressure.

[0009] Optionally, determining the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body in S2 specifically includes:

[0010] determining the uniformly distributed load applied by the third rock pile to the top surface of the fourth rock pile and the earth pressure coefficient of the dam body;

[0011] The horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body is determined according to 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:

[0013] 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.

[0014] Optionally, the determination of the earth pressure coefficient of the dam body is specifically as follows:

[0015] When the filling elevation of the dam body is less than or equal to the top elevation of the high toe wall, the bottom pressure coefficient is used as the earth pressure coefficient;

[0016] When the filling elevation of the dam body is greater than the top elevation of the high toe wall and less than or equal to the filling completion elevation of the second rock pile, the earth pressure coefficient is determined based on the bottom pressure coefficient and the top pressure coefficient;

[0017] When the filling elevation of the dam body is greater than the filling completion elevation of the second rockfill body and is less than or equal to the top elevation of the rockfill dam, the top pressure coefficient is used as the earth pressure coefficient.

[0018] Optionally, the earth pressure coefficient is determined according to the bottom pressure coefficient and the top pressure coefficient, specifically:

[0019] The difference between the top pressure coefficient and the bottom pressure coefficient is obtained, and the sum of 2 / 3 times of the difference and the bottom pressure coefficient is taken as the earth pressure coefficient.

[0020] Optionally, the top pressure coefficient is determined according to the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the top elevation of the high toe wall and the top elevation of the rockfill dam.

[0021] Optionally, determining the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body according to the uniformly distributed load and the earth pressure coefficient specifically includes:

[0022] Obtaining half of the product of the square value of the top elevation of the high toe wall and the weight of the rockfill as a first product, and obtaining the product of the top elevation of the high toe wall and the uniformly distributed load as a second product;

[0023] A sum of the first product and the second product is obtained, and the product of the sum and the earth pressure coefficient is used as the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body.

[0024] Optionally, the determining of the gravity of the first rock pile in S2 is specifically:

[0025] The product of the square value of the top elevation of the high toe wall and the downstream slope ratio of the high toe wall is obtained as the third product, and half of the product of the third product and the weight of the rockfill is obtained as the gravity of the first rockfill body.

[0026] Optionally, the step of determining the gravity of the second rock pile in S2 is specifically:

[0027] Obtaining the product of the square value of the top elevation of the high toe wall and the square value of the downstream slope ratio of the high toe wall as a fourth product, and obtaining the product of the fourth product and the weight of the rockfill as a fifth product;

[0028] A half of the ratio of the fifth product to the upstream face slope ratio of the rockfill dam is obtained as the gravity of the second rockfill body.

[0029] Optionally, the S3 specifically includes:

[0030] Obtaining the square of the sum of the gravity of the first rock pile and the gravity of the second rock pile as a first square value, and obtaining the square of the horizontal earth pressure as a second square value;

[0031] The square root of the sum of the first square value and the second square value is obtained as the earth pressure on the high toe wall during the construction period.

[0032] The beneficial effects that the present invention can produce include:

[0033] The present invention provides an analysis method for the soil pressure on the high toe wall during the construction period of a dam structure. The rockfill dam is divided into four rockfill bodies 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, and the influence of each rockfill body on the soil pressure on the high toe wall is considered respectively, so as to derive a calculation formula for the soil pressure on the high toe wall. The proposed formula has clear physical meaning, can well simulate the change and development of the soil pressure at the interface between the high toe wall and the rockfill body during the construction period, and has high accuracy.

[0034] The present invention provides an analysis method for the earth pressure on the high toe wall during the construction period of the dam structure. The earth pressure on the high toe wall is expressed as a power function related to the dam height, and is compared and verified with monitoring data and finite element calculation results. The rules are consistent and the numerical values ​​differ by less than 5%. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1A flow chart of a method for analyzing earth pressure on a high toe wall during construction of a dam structure provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of a high toe wall and a rockfill dam structure provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of the elevation of the rockfill body to the top of the high toe wall provided in an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of a first-level rockfill body filled to the top elevation of a high toe wall provided in an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of a fifth level of rockfill body filled to the top elevation of a high toe wall provided by an embodiment of the present invention;

[0040] Figure 6 A schematic diagram of rockfill body partitioning provided by an embodiment of the present invention;

[0041] Figure 7 A schematic diagram showing a comparison between theoretically calculated values ​​of earth pressure at various filling elevations and finite element calculation results provided in an embodiment of the present invention;

[0042] Figure 8 A schematic diagram showing the comparison of theoretical calculation results, finite element calculation results and monitoring data of the soil pressure on the back of the high toe wall provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0043] The present invention is described in detail below in conjunction with embodiments, but the present invention is not limited to these embodiments.

[0044] The embodiment of the present invention provides a method for analyzing the earth pressure on the high toe wall during the construction period of the dam structure. Figure 1 As shown, the method includes:

[0045] S1. Use the plumb plane passing through the bottom of the high toe wall and the horizontal plane passing through the top of the high toe wall 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.

[0046] refer to Figure 2 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.

[0047] S2. Determine the gravity of the first rock pile and the second rock pile, and the horizontal earth pressure on the interface between the first rock pile and the fourth rock pile.

[0048] (1) Determine the gravity of the first rockfill body by obtaining the product of the square value of the top elevation of the high toe wall and the slope ratio of the downstream surface of the high toe wall as the third product, and obtain half of the product of the third product and the weight of the rockfill body as the gravity of the first rockfill body. The specific calculation formula is as follows:

[0049] ;

[0050] 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 top elevation of the high toe wall.

[0051] (2) Determine the gravity of the second rockfill body, specifically: first obtain the product of the square value of the top elevation of the high toe wall and the square value of the downstream slope ratio of the high toe wall as the fourth product, and obtain the product of the fourth product and the weight of the rockfill as the fifth product; then obtain half of the ratio of the fifth product and the upstream slope ratio of the rockfill dam as the gravity of the second rockfill body. The specific calculation formula is as follows:

[0052] ;

[0053] 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 top elevation of the high toe wall.

[0054] (3) Determine the horizontal earth pressure on the interface between the first rock pile and the fourth rock pile, including:

[0055] (a) Determine 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.

[0056] 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.

[0057] Among them, the earth pressure coefficient of the dam body is determined as follows:

[0058] When the filling elevation of the dam body is less than or equal to the top elevation of the high toe wall, the bottom pressure coefficient shall be taken as the earth pressure coefficient.

[0059] When the filling elevation of the dam body is greater than the top elevation of the high toe wall and less than or equal to the filling completion elevation of the second rock pile, the earth pressure coefficient is determined based on the bottom pressure coefficient and the top pressure coefficient.

[0060] Specifically, the difference between the top pressure coefficient and the bottom pressure coefficient is obtained, and the sum of 2 / 3 times the difference and the bottom pressure coefficient is taken as the earth pressure coefficient.

[0061] When the filling elevation of the dam body is greater than the filling completion elevation of the second rockfill body and is less than or equal to the top elevation of the rockfill dam, the top pressure coefficient shall be taken as the earth pressure coefficient.

[0062] In practical applications, the earth pressure coefficients at different filling heights are different, so the rockfill body above the top elevation of the high toe wall is divided into two areas by three filling elevations, see Figure 6 As shown, the three filling elevations are the top elevation of the high toe wall , The second pile of rock filling is completed at the elevation , Rockfill dam top elevation .

[0063] Fill the dam to the top elevation of the high toe wall When ;

[0064] When the dam body is filled to the second pile of rock, the filling level is completed. When ;

[0065] Filling to the top elevation of the rockfill dam When .

[0066] in, is the earth pressure coefficient, is the bottom pressure coefficient, is the top pressure coefficient.

[0067] The above bottom pressure coefficient The corresponding fill elevation is the top elevation of the high toe wall ,like Figure 6 At this time, the dam body only has the first and fourth piles of rocks. It is only related to the properties of rockfill materials. Based on multiple engineering data of different materials, the finite element numerical simulation method is used to compare the earth pressure size of the theoretical formula with the earth pressure size obtained by finite element numerical simulation. It is demonstrated that: when the rockfill material is soft rock, Take 0.20; when the rockfill material is gravel or limestone, Take 0.40.

[0068] The above top pressure coefficient is determined based on the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the top elevation of the high toe wall and the top elevation of the rockfill dam.

[0069] Specifically, the orthogonal test method and the multivariate linear regression method can be used to obtain The determination formula of .

[0070] When the rockfill material is soft rock, The values ​​are shown in the following formula.

[0071] ;

[0072] When the rockfill material is gravel or limestone, The values ​​are shown in the following formula.

[0073] ;

[0074] In the formula, is the top pressure coefficient, is the upstream slope ratio of the rockfill dam; is the elevation of the top of the high toe wall; is the top elevation of the rockfill dam, is the slope ratio of the downstream face of the high toe wall.

[0075] (b) Determine the horizontal earth pressure at the interface between the first rock pile and the fourth rock pile based on the uniformly distributed load and the earth pressure coefficient.

[0076] Specifically, the method includes: firstly obtaining half of the product of the square value of the top elevation of the high toe wall and the weight of the rockfill as the first product, and obtaining the product of the top elevation of the high toe wall and the uniformly distributed load as the second product; then obtaining the sum of the first product and the second product, and taking the product of the sum and the earth pressure coefficient as the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body.

[0077] The specific calculation formula is as follows:

[0078] ;

[0079] In the formula, is the horizontal earth pressure on the interface between the first rock pile and the fourth rock pile; is the earth pressure coefficient; is the weight of the rock pile; is the uniformly distributed load applied by the third rock pile on the top surface of the fourth rock pile; for The height of the surface is the top elevation of the high toe wall .

[0080] S3. Determine the earth pressure on the high toe wall during the construction period according to the gravity of the first rock pile and the second rock pile, as well as the horizontal earth pressure.

[0081] Specifically, firstly, the square of the sum of the gravity of the first rock pile and the gravity of the second rock pile is obtained as the first square value, and the square of the horizontal earth pressure is obtained as the second square value; then the square root of the sum of the first square value and the second square value is obtained as the earth pressure on the high toe wall during the construction period.

[0082] The specific calculation formula is as follows:

[0083] ;

[0084] In the formula, is the earth pressure on the high toe wall during construction; is the gravity of the first pile of rocks; is the gravity of the second pile of rocks; is the horizontal earth pressure.

[0085] The derivation process of the calculation formula for the earth pressure on the high toe wall during the construction period is described in detail below.

[0086] In actual engineering, since the rockfill dam panel is very thin and small in size compared to the dam body and high toe wall, it can be simplified. The simplified structure is shown in Figure 2 When the dam is filled, it is assumed that the rockfill part of the dam body that is higher than the top elevation of the high toe wall is divided into The filling is completed. For high toe walls, It is a rockfill body. Draw an imaginary plumb plane along the bottom of the high toe wall. , make an imaginary horizontal plane along the top of the high toe wall Divide the backfill behind the wall into four parts: Below the surface, The first pile of rocks on the left , above face, The second pile of rocks on the left , above face, The third pile of rocks on the right , Below the surface, The fourth pile of rocks on the right .

[0087] Will The second and third rock piles above the surface are simplified as surface pressure, and the gravity of the second rock pile is calculated and applied to the top of the first rock pile. Calculate the gravity of the third rock pile and apply it to the top of the fourth rock pile in the form of a uniform load. Among them, the third rockfill can take into account the graded loading of the dam body, that is, calculate the weight of the rockfill with graded loading, convert it into a uniformly distributed load, and then add it to the top of the fourth rockfill. Face overlay.

[0088] Assumptions For a smooth surface, according to Rankine earth pressure theory, the pressure acting on Horizontal earth pressure on surface Then calculate the gravity of the first and second piles of rocks , . Then by , and Get the effect on Earth pressure on surface .

[0089] like Figure 3 As shown in the figure, when the rockfill is filled to the top elevation of the high toe wall, there are only the first rockfill and the fourth rockfill. The gravity on the first rockfill is:

[0090] ;

[0091] 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 top elevation of the high toe wall.

[0092] interface The horizontal earth pressure is:

[0093] ;

[0094] In the formula, is the horizontal earth pressure on the interface between the first rock pile and the fourth rock pile; is the earth pressure coefficient; is the weight of the rock pile; for The height of the surface is the top elevation of the high toe wall .

[0095] At this time, the earth pressure on the AB surface between the high toe wall and the rockfill dam is:

[0096] ;

[0097] In the formula, is the earth pressure on the high toe wall during construction; is the gravity of the first pile of rocks; is the horizontal earth pressure.

[0098] like Figure 4 As shown in Figure 1, when the filling reaches the first level of rockfill above the top elevation of the high toe wall, the filling height is , the gravity on the first pile of rocks is:

[0099] ;

[0100] The gravity on the second pile of rocks is:

[0101] ;

[0102] Where: 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 slope ratio of the downstream face of the high toe wall; is the upstream slope ratio of the rockfill dam; is the elevation of the top of the high toe wall; is the height of the rockfill loading.

[0103] Calculate the gravity of the third rock pile and apply it to the top of the fourth rock pile as a uniformly distributed load noodle.

[0104] ;

[0105] In the formula, To be applied on the top of the fourth pile of rocks Uniformly distributed load on the surface; The top of the fourth pile of rocks Length.

[0106] interface The horizontal earth pressure is:

[0107] .

[0108] Boundary between high toe wall and rockfill The earth pressure on the surface is:

[0109] .

[0110] like Figure 5 As shown in the figure, until the last level of rockfill is filled above the top elevation of the high toe wall, the gravity exerted on the first rockfill is:

[0111] .

[0112] The gravity on the second pile of rocks is:

[0113] .

[0114] Calculate the gravity of the fifth layer of the third rockpile and apply it to the top of the fourth rockpile in the form of a uniformly distributed load. face, and with the front The uniformly distributed load converted from the gravity of the rockfill layer is superimposed ( is the number of grading layers).

[0115] ;

[0116] In the formula, The third pile of rocks Uniformly distributed load transformed from the gravity of layered rockfill.

[0117] At this time, the interface The horizontal earth pressure is:

[0118] .

[0119] Then, the interface between the high toe wall and the rockfill dam The earth pressure on is:

[0120] .

[0121] Based on the derivation of the above formula, accurate determination , The value of It is the key to calculating the soil pressure behind the high toe wall during the construction period.

[0122] for For example, the corresponding filling elevation is the top elevation of the high toe wall. ,like Figure 6 As shown. The dam body consists of only the first and fourth piles of rocks. It is only related to the properties of rockfill materials. Select a number of different rockfill projects, taking gravel, limestone and soft rock as representatives, and calculate the earth pressure of the above theoretical formula and the earth pressure obtained by finite element numerical simulation under different rockfill lithology to determine The calculation results are shown in Table 1. For rockfill materials of different properties, The value of is also different. But for gravel and limestone, The values ​​of are basically the same. From the calculation results, when the rockfill material is soft rock, Take 0.20, when the rockfill material is gravel or limestone, Take 0.40.

[0123] Table 1 Comparison of the maximum difference between theoretical formula calculation values ​​and finite element calculation values ​​for different rockfill materials

[0124]

[0125] for For example, the orthogonal test method and the multiple linear regression method can be used to obtain the determined formula.

[0126] When the rockfill material is soft rock, The values ​​are as follows:

[0127] ;

[0128] When the rockfill material is gravel or limestone, The values ​​are shown in the following formula:

[0129] ;

[0130] In the formula, is the top pressure coefficient, is the upstream slope ratio of the rockfill dam; is the elevation of the top of the high toe wall; is the top elevation of the rockfill dam, is the slope ratio of the downstream face of the high toe wall.

[0131] In the following, the observation data of the monitoring prototype and the finite element simulation results of a certain engineering mosaic concrete face rockfill dam are compared with the calculation results of the theoretical formula proposed in the present invention.

[0132] The filling material of the dam body is basically limestone, so The upstream slope ratio of the rockfill dam is , the ratio of the top elevation of the high toe wall to the top elevation of the rockfill dam , the downstream slope ratio of the high toe wall According to the formula proposed by the present invention, .in, It is calculated by the following formula.

[0133] .

[0134] The normal force at the interface between the high toe wall and the rockfill is calculated using the finite element method and compared with the result calculated by the above formula. Figure 7 shown.

[0135] It can be seen from the figure that the soil pressure values ​​at all levels calculated by the theoretical formula are close to the results of finite element calculation. The maximum relative error of the 10 filling elevations is 5.19%, the minimum relative error is 0.04%, and the average relative error is 2.32%. It can be seen that the soil pressure values ​​calculated by the theoretical formula during the construction period are close to the results of finite element calculation.

[0136] In order to prove the rationality of the finite element numerical simulation, the soil pressure distribution on the back of the high toe wall obtained by the finite element numerical simulation is compared with the monitoring data. Figure 8 As shown in the figure, the finite element earth pressure simulation value, the theoretical formula earth pressure calculation value, and the monitoring data earth pressure monitoring value are relatively close. When the filling elevation is 2680.00m, the relative error between the theoretical formula earth pressure calculation value and the monitoring data earth pressure monitoring value is relatively large, which is -6.54%.

[0137] In the prior art, the calculation of the earth pressure at the interface between the high toe wall and the rockfill dam is often calculated using the Coulomb earth pressure theory. Regardless of active earth pressure or passive earth pressure, this method assumes that the earth pressure changes in a triangular distribution pattern along the wall back and wall height. However, the surface load form 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. The calculation method proposed in the present invention shows that the earth pressure is a power function related to the dam body height and the high toe wall height, and is compared and verified with the monitoring data and the results of finite element calculation. The law is consistent and the numerical value difference is within 5%.

[0138] During the construction of a rockfill dam, as the dam height increases, the earth pressure at the interface between the high toe wall and the rockfill dam will gradually increase. However, the active earth pressure and passive earth pressure calculated by the Coulomb earth pressure theory currently used are independent of the dam height, which is obviously unreasonable. The method proposed in the present invention takes the dam height into consideration, and its calculation results are more reasonable and scientific.

[0139] The present invention provides an empirical formula for calculating soil pressure during the construction period. Compared with actual projects, the proposed formula can well simulate the change and development of soil pressure at the interface between the high toe wall and the rockfill body during the construction period with high accuracy.

[0140] The soil pressure calculation idea proposed in 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.

[0141] 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 during the construction period of a dam structure, characterized in that: The method comprises: S1, using a vertical plane passing through the bottom of the high toe wall and a horizontal plane passing through the top of the high toe wall 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; S2, determining 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; and determining the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body according to the uniformly distributed load and the earth pressure coefficient; S3, determining the earth pressure on the high toe wall during the construction period according to the gravity of the first rock pile and the second rock pile, and the horizontal earth pressure; The step of determining the uniformly distributed load applied by the third rockfill body to the top surface of the fourth rockfill body is specifically as follows: determining the gravity of the third rockpile, and converting the gravity of the third rockpile into a uniformly distributed load applied to the top surface of the fourth rockpile; The determination of the earth pressure coefficient of the dam body is specifically as follows: When the filling elevation of the dam body is less than or equal to the top elevation of the high toe wall, the bottom pressure coefficient is used as the earth pressure coefficient; When the filling elevation of the dam body is greater than the top elevation of the high toe wall and less than or equal to the filling completion elevation of the second rockfill body, the difference between the top pressure coefficient and the bottom pressure coefficient is obtained, and the sum of 2 / 3 times of the difference and the bottom pressure coefficient is taken as the earth pressure coefficient; When the filling elevation of the dam body is greater than the filling completion elevation of the second rockfill body and is less than or equal to the top elevation of the rockfill dam, the top pressure coefficient is used as the earth pressure coefficient.

2. The method according to claim 1, characterized in that The top pressure coefficient is determined according to the upstream face slope ratio of the rockfill dam, the downstream face slope ratio of the high toe wall, the top elevation of the high toe wall and the top elevation of the rockfill dam.

3. The method according to claim 1, characterized in that The determining, according to the uniformly distributed load and the earth pressure coefficient, the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body specifically includes: Obtaining half of the product of the square value of the top elevation of the high toe wall and the weight of the rockfill as a first product, and obtaining the product of the top elevation of the high toe wall and the uniformly distributed load as a second product; A sum of the first product and the second product is obtained, and the product of the sum and the earth pressure coefficient is used as the horizontal earth pressure on the interface between the first rockfill body and the fourth rockfill body.

4. The method according to claim 1, characterized in that The step of determining the gravity of the first rock pile in S2 is specifically: The product of the square value of the top elevation of the high toe wall and the downstream slope ratio of the high toe wall is obtained as the third product, and half of the product of the third product and the weight of the rockfill is obtained as the gravity of the first rockfill body.

5. The method according to claim 1, characterized in that The step of determining the gravity of the second rock pile in S2 is specifically: Obtaining the product of the square value of the top elevation of the high toe wall and the square value of the downstream slope ratio of the high toe wall as a fourth product, and obtaining the product of the fourth product and the weight of the rockfill as a fifth product; A half of the ratio of the fifth product to the upstream face slope ratio of the rockfill dam is obtained as the gravity of the second rockfill body.

6. The method according to claim 1, characterized in that The S3 specifically includes: Obtaining the square of the sum of the gravity of the first rock pile and the gravity of the second rock pile as a first square value, and obtaining the square of the horizontal earth pressure as a second square value; The square root of the sum of the first square value and the second square value is obtained as the earth pressure on the high toe wall during the construction period.

Images