Method for evaluating deep anti-sliding stability of gravity dam in strong earthquake area with complex sliding surface

Abstract

The application discloses a kind of strong earthquake area complex sliding surface composition's gravity dam deep anti-sliding stability evaluation method, comprising: S1, the finite element analysis model of dam-foundation system of deep sliding block body formed by weak structural plane in foundation rock mass is constructed;S2, based on the model, dam-deep sliding block body is divided into equal number of strip block with deep sliding block body structural plane along vertical direction;S3, extract each time step dynamic internal force of each sliding surface on each strip block, respectively with static load on each strip block as external force, solve the deep anti-sliding stability resistance ratio coefficient of gravity dam at each time step gradually, and draw the time history curve of deep anti-sliding stability ratio coefficient;S4, according to the minimum deep anti-sliding stability ratio coefficient in time history curve, the deep anti-sliding stability of gravity dam is evaluated.The method can realize comprehensive and comprehensive evaluation on strong earthquake area gravity dam deep anti-sliding stability aseismic safety, to ensure that dam can long-term safe operation.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of gravity dam anti-sliding stability analysis, and particularly relates to a method for evaluating deep anti-sliding stability of a gravity dam with complex sliding surfaces in a strong earthquake area. BACKGROUND

[0002] In the process of dam design, due to the defects such as weak interlayer and low-angle fissure in the dam site rock mass, deep sliding failure along the weak structural surface in the rock mass of the dam foundation may occur under the action of strong earthquake, which may lead to deep sliding instability of the dam. The existing static and dynamic safety evaluation of deep anti-sliding stability of the gravity dam is mainly based on the response spectrum method of massless foundation, however, the anti-sliding stability of the dam under the action of earthquake is obviously different from that under the action of static force. In fact, the earthquake load shows significant reciprocating variation characteristics, and the deep sliding instability of the dam is a gradual accumulation process of residual deformation. The evaluation index of instantaneous deep anti-sliding stability obtained by the dynamic analysis based on the response spectrum method of massless foundation may exceed the allowable value, which does not necessarily represent the final deep sliding instability failure of the dam.

[0003] Therefore, the key problem of the seismic safety evaluation of deep anti-sliding stability of the gravity dam is to propose corresponding evaluation indexes and criteria of deep anti-sliding stability for different calculation and analysis methods and models, and to form a complete evaluation system of "method-model-evaluation" matching each other. The analysis method and model show a progressive process from shallow to deep and from simple to complex, and the evaluation index and criterion gradually change from being conservative to being close to the engineering practice. SUMMARY

[0004] In view of the above problems in the prior art, the method for evaluating deep anti-sliding stability of a gravity dam with complex sliding surfaces in a strong earthquake area provided by the present application solves the problem that the evaluation index and criterion obtained based on the response spectrum method of massless foundation cannot accurately reflect the deep anti-sliding stability of the gravity dam.

[0005] In order to achieve the above-mentioned application purposes, the technical scheme adopted by the present application is as follows:

[0006] S1, constructing a dam-foundation system finite element analysis model of a deep sliding block composed of weak structural surfaces in the foundation rock mass;

[0007] S2, based on the constructed dam-foundation system finite element analysis model, dividing the dam-deep sliding block into blocks equal to the number of structural surfaces of the deep sliding block along the vertical direction at each boundary of the structural surfaces of the deep sliding block;

[0008] S3, extract each time step dynamic internal force of each block on the sliding surface, and together with the static load acting on each block as external force, gradually solve the deep anti-sliding stability resistance ratio coefficient of gravity dam at each time step, and draw the time history curve of deep anti-sliding stability resistance ratio coefficient;

[0009] S4, according to the minimum deep anti-sliding stability resistance ratio coefficient in the time history curve, evaluate the deep anti-sliding stability of the gravity dam.

[0010] Further, in the step S3, the method for solving the deep anti-sliding stability resistance ratio coefficient of the gravity dam is specifically:

[0011] S31, based on the resistance function and effect function of block i at time step j, construct the deep anti-sliding stability resistance ratio coefficient calculation formula of the whole foundation of the gravity dam at each time step;

[0012] S32, based on the deep anti-sliding stability resistance ratio coefficient of each block, simplify the deep anti-sliding stability resistance ratio coefficient calculation formula;

[0013] S33, based on the deep anti-sliding stability resistance ratio coefficient calculation formula of each block, construct N-1 equations about the sum of shear forces on both sides of block i at each time step j, and combine the balance equation of internal force of deep anti-sliding system of gravity dam foundation to solve the deep anti-sliding stability resistance ratio coefficient of each time step The sum of shear forces between the lateral contact surfaces of each block ;

[0014] S34, put Into the deep anti-sliding stability resistance ratio coefficient calculation formula, and solve the deep anti-sliding stability resistance ratio coefficient of gravity dam at each time step j.

[0015] Further, in the step S31, the deep anti-sliding stability resistance ratio coefficient Calculation formula is:

[0016]

[0017] In the formula, Indicates the deep anti-sliding stability resistance ratio coefficient of block i at time step j, Indicates the resistance function of block i at time step j, Indicates the effect function of block i at time step j, Indicates the standard value of material performance, Indicates the material performance sub-coefficient, Indicates the standard value of geometric parameter, Indicates the structure importance coefficient, Indicates the deep anti-sliding stability bearing capacity limit state structure coefficient, Indicates the design condition coefficient. Indicates the partial factor for permanent effects. Indicates the standard value for permanent effect. Indicates the variable action partial factor. This represents the standard value of the variable action.

[0018] Furthermore, in step S32, the simplified deep anti-slip stability resistance ratio coefficient The calculation formula is:

[0019]

[0020] In the formula, , ,…, Let i and N represent the resistance functions of blocks at time step j, respectively. , ,…, This represents the effect function of block i~N at time step j.

[0021] Furthermore, in step S4, when the minimum deep anti-slip stability ratio coefficient... At that time, the gravity dam is within the deep sliding stability range and has deep anti-sliding stability;

[0022] When the minimum deep anti-skid stability ratio coefficient At that time, based on the cumulative duration of the deep anti-slip stability ratio coefficient at each time step. The deep anti-sliding stability of gravity dams was analyzed.

[0023] Furthermore, in step S4, when the following occurs... Cumulative duration At that time, the gravity dam was outside the deep sliding stability range. Considering the nonlinearity of the contact between the dam body, the deep sliding block, and the foundation, the deep anti-sliding stability of the gravity dam was further evaluated through nonlinear time history response analysis.

[0024] When it appears Cumulative duration With total duration percentage Less than At that time, the gravity dam is within the deep sliding stability range and has deep anti-sliding stability;

[0025] When it appears Cumulative duration With total duration percentage Greater than At that time, the gravity dam was outside the deep sliding stability range. Considering the nonlinearity of the contact between the dam body, the deep sliding block, and the foundation, the deep anti-sliding stability of the gravity dam was further evaluated through nonlinear time history response analysis.

[0026] in, and All are set constants less than 1.

[0027] Furthermore, the specific method for further evaluating the deep anti-sliding stability of medium gravity dams is as follows:

[0028] For the finite element analysis model of the dam-foundation system, a contact model is used to consider the nonlinearity between the dam body, deep sliding block and foundation, and a nonlinear dynamic time history response analysis considering the radiation damping foundation effect is carried out.

[0029] Based on the nonlinear dynamic time history response analysis results, the sum of the sliding areas of each sliding surface of the deep sliding block was calculated. With total sliding surface area percentage ;

[0030] judge Whether it is true or not; among them, To set a threshold;

[0031] If so, the gravity dam is within the range of deep sliding stability and has deep anti-sliding stability;

[0032] If not, then the gravity dam is at risk of deep anti-sliding instability and failure, and requires reinforcement.

[0033] Furthermore, the total sliding surface area The calculation formula is:

[0034]

[0035] The sum of the sliding areas of each sliding surface of the deep sliding block. The calculation formula is:

[0036]

[0037] In the formula, This indicates the area affected by each contact point on the contact surface. The area affected by the contact point where sliding failure occurs on the contact surface. This represents the total number of contact point pairs.

[0038] The beneficial effects of this invention are as follows:

[0039] The application provides a deep anti-sliding stability evaluation method and corresponding evaluation criteria based on a massless foundation linear elastic dynamic time history, which can solve the problem that the dynamic analysis method based on the massless foundation response spectrum method cannot reflect the significant reciprocating variation characteristics of the earthquake load, and the instantaneous deep anti-sliding stability evaluation index obtained by the massless foundation response spectrum method exceeds the allowable value, which does not necessarily represent the final deep sliding instability and damage of the dam.

[0040] Based on the conclusion obtained by the massless foundation linear elastic time history method, the contact model is used to consider the contact nonlinearity among the dam, the deep sliding block and the foundation for the gravity dam-foundation system, the nonlinear dynamic time history response considering the radiation damping foundation effect is researched, the deep anti-sliding instability and damage evaluation index of the gravity dam and the corresponding evaluation criteria are provided, and the comprehensive and overall evaluation of the deep anti-sliding stability and seismic safety of the gravity dam in the strong earthquake area can be realized, so as to ensure the long-term safe operation of the dam.

[0041] The application provides the corresponding deep anti-sliding stability evaluation index and evaluation criteria according to different calculation and analysis methods and models for the key problem of the deep anti-sliding stability and seismic safety evaluation of the gravity dam, forms a complete evaluation system of the method-model-evaluation mutual matching, presents the progressive process from shallow to deep and from simple to complex in the analysis method and model, and gradually changes from the conservative evaluation index and evaluation criteria to the engineering practice. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The application provides a flow chart of the deep anti-sliding stability evaluation method of the gravity dam with complex sliding surface in the strong earthquake area.

[0043] Figure 2 The application provides a schematic diagram of the deep anti-sliding stability strip and block division (a) and calculation method (b) of the gravity dam.

[0044] Figure 3 The application provides a schematic diagram of the deep anti-sliding stability evaluation criteria of the gravity dam. DETAILED DESCRIPTION

[0045] The specific embodiments of the application are described below, so that those skilled in the art can understand the application, but it should be clear that the application is not limited to the scope of the specific embodiments, and for those skilled in the art, it is obvious that various changes are within the spirit and scope of the application defined and determined by the appended claims, and all the application and creation utilizing the concept of the application are within the scope of protection.

[0046] The application is based on the need for the evaluation of the deep anti-sliding stability and the seismic safety of gravity dams under strong earthquake forces, and the defects of the existing evaluation indexes and criteria based on the massless foundation response spectrum, and proposes an evaluation method for the deep anti-sliding stability of gravity dams with complex sliding surfaces in strong earthquake regions, so as to realize comprehensive and overall evaluation of the deep anti-sliding stability and the seismic safety of gravity dams in strong earthquake regions, and ensure the long-term safe operation of the dams.

[0047] The evaluation method for the deep anti-sliding stability of gravity dams with complex sliding surfaces in strong earthquake regions in the embodiments of the application, as shown in Figure 1 , includes the following steps:

[0048] S1, constructing a dam-foundation system finite element analysis model of deep sliding blocks composed of internal weak structural surfaces of foundation rock mass;

[0049] S2, based on the constructed dam-foundation system finite element analysis model, dividing the dam-deep sliding blocks into blocks equal to the number of structural surfaces of the deep sliding blocks along the vertical direction at each boundary of the structural surfaces;

[0050] S3, extracting the dynamic internal force of each time step of the sliding surface of each block, respectively, and together with the static load acting on each block as external force, gradually solving the action ratio coefficient of the deep anti-sliding stability of gravity dams at each time step, and drawing a time history curve of the action ratio coefficient of the deep anti-sliding stability;

[0051] S4, evaluating the deep anti-sliding stability of the gravity dam according to the minimum action ratio coefficient of the deep anti-sliding stability in the time history curve.

[0052] In step S1 in the embodiments of the application, a dam-foundation system finite element analysis model of deep sliding blocks composed of internal weak structural surfaces of foundation rock mass is constructed according to the dam site topographic features and the physical properties of the bedrock in the research area, and the massless foundation linear elastic dynamic time history response is researched.

[0053] In step S2 of the embodiments of the application, as shown in Figure 2 , the dam-deep sliding blocks are divided into blocks equal to the number of structural surfaces along the vertical direction at each boundary of the structural surfaces of the deep sliding blocks.

[0054] In step S3 of the embodiments of the application, according to the block division result, the dynamic internal force of each time step of the sliding surface of each block is extracted, respectively, and together with the static load acting on each block as external force, the action ratio coefficient of the deep anti-sliding stability of gravity dams is gradually solved at each time step , and then the time history curve is given , and the total time step number is . ​

[0055] In step S3 of this embodiment, the process of solving the ratio coefficient of deep anti-sliding stability resistance of the gravity dam is based on the gravity dam design code and considers seismic loads to solve the ratio coefficient of deep anti-sliding stability resistance of the gravity dam. Therefore, the relevant coefficients are all taken according to the gravity dam design code. Specifically, the solution process is as follows:

[0056] S31. Based on the resistance function and action effect function of block i at time step j, construct the calculation formula for the deep anti-sliding stability resistance ratio coefficient of the entire gravity dam foundation at each time step.

[0057] S32. Based on the fact that the coefficients of the deep anti-sliding stability resistance of each block are equal, the calculation formula for the coefficients of the deep anti-sliding stability resistance is simplified.

[0058] S33. Based on the calculation formula of the deep anti-sliding stability resistance ratio coefficient of each block, N-1 equations about the sum of shear forces on both sides of block i are constructed at each time step j. Combined with the equilibrium equation of the internal forces of the deep anti-sliding system of the gravity dam foundation, the equations for each time step are solved to obtain the equations for each time step. The sum of shear forces between the lateral contact surfaces of each block ;

[0059] S34, will Substituting the formula for calculating the ratio of deep anti-sliding stability resistance, the ratio of deep anti-sliding stability resistance of the gravity dam at each time step j is obtained.

[0060] In step S31 of this embodiment, the resistance function of block i at time step j and effect function They are respectively:

[0061]

[0062]

[0063] In the formula, Represents bars The coefficient of friction against shear failure of deep sliding block structure surfaces. Represents bars The weight of the deep sliding block. Represents bars The dam body's own weight covers the deep sliding blocks. Represents bars Inclination angle of deep sliding block structure surface express Time step block The sum of the shear forces on both sides, pointing upstream, is considered positive. Indicates the known Time Step Angle with the horizontal direction, representing block water pressure on deep sliding block structure surface, representing block side water pressure resultant force, representing block subjected to other horizontal static load, representing time step block horizontal seismic load on deep sliding block structure surface, representing time step block vertical seismic load on deep sliding block structure surface, representing block shear resistance cohesion on deep sliding block structure surface, representing block deep sliding block structure surface area.

[0064] each time step resistance action ratio coefficient of each block are equal, the gravity dam deep sliding block reaches limit equilibrium, then in step S31, the gravity dam foundation whole and each block deep anti-slide stability resistance action ratio coefficient calculation formula is as follows:

[0065]

[0066] in the formula, representing deep anti-slide stability resistance action ratio coefficient of block i in time step j, representing resistance function of block i in time step j, representing action effect function of block i in time step j, representing material performance standard value, representing material performance subcoefficient, representing geometric parameter standard value, representing structure importance coefficient, representing deep anti-slide stability bearing capacity limit state structure coefficient, representing design condition coefficient, representing permanent action subcoefficient, representing permanent action standard value, representing variable action subcoefficient, representing variable action standard value.

[0067] resistance action ratio coefficient of each block are equal, then:

[0068]

[0069] For the same dam deep anti-sliding section, are same, then in step S32, the simplified deep anti-sliding stability resistance action ratio coefficient The calculation formula is:

[0070]

[0071] In the formula, , ,…, Respectively, the resistance function of block i~N in time step j, , ,…, The action effect function of block i~N in time step j.

[0072] In step S33, in each time step The Equations about Can be obtained, and the balance formula of internal force in the deep anti-sliding system of dam foundation is combined:

[0073]

[0074] That is, the Equations about Can be obtained, and each time step The shear force between each block lateral contact surface .

[0075] In step S34, the Is substituted into the calculation formula of resistance action ratio To obtain the deep anti-sliding stability resistance action ratio coefficient of gravity dam in each time step j .

[0076] In step S4 of the embodiment of the application, when the minimum deep anti-sliding stability action ratio coefficient The gravity dam is in the deep sliding stability range and has deep anti-sliding stability; specifically, In the entire seismic time history, the deep anti-sliding stability action ratio coefficient And the corresponding cumulative duration ratio Of total duration Figure 3 Are out of the shadow part, the gravity dam can maintain deep anti-sliding stability.

[0077] In step S4 of the embodiment of the application, when the minimum deep anti-sliding stability action ratio coefficient According to the cumulative duration of deep anti-sliding stability action ratio coefficient of each time step , the deep anti-sliding stability of the gravity dam is analyzed; the analysis process is as follows:

[0078] When it appears Cumulative duration At that time, the gravity dam was outside the deep sliding stability range. Considering the nonlinear contact between the dam body, the deep sliding block, and the foundation, the deep anti-sliding stability of the gravity dam was further evaluated through nonlinear time history response analysis; specifically, the following occurred... Cumulative duration At that time, the deep anti-sliding stability ratio coefficient during the entire earthquake motion time history and its corresponding cumulative duration In Figure 3 Within the shaded area, the gravity dam may experience deep sliding instability, which requires further evaluation using nonlinear time history analysis;

[0079] When it appears Cumulative duration With total duration percentage Less than At that time, the gravity dam is within the deep sliding stability range and possesses deep anti-sliding stability; specifically, the deep anti-sliding stability ratio coefficient during the entire seismic motion time history... and its corresponding cumulative duration In Figure 3 Outside the shaded area, gravity dams can maintain deep anti-sliding stability;

[0080] When it appears Cumulative duration With total duration percentage Greater than At that time, the gravity dam was outside the deep sliding stability range. Considering the nonlinear contact between the dam body, the deep sliding block, and the foundation, the deep anti-sliding stability of the gravity dam was further evaluated through nonlinear time history response analysis. Specifically, the deep anti-sliding stability ratio coefficient was calculated throughout the entire seismic motion time history. and its corresponding cumulative duration In Figure 3 Within the shaded area, the gravity dam may experience deep sliding instability, which requires further evaluation using nonlinear time history analysis;

[0081] in, and All are set constants less than 1.

[0082] In this embodiment, the method for further evaluating the deep anti-sliding stability of a gravity dam is as follows:

[0083] For the finite element analysis model of the dam-foundation system, a contact model is used to consider the nonlinearity between the dam body, deep sliding block and foundation, and a nonlinear dynamic time history response analysis considering the radiation damping foundation effect is carried out.

[0084] Based on the nonlinear dynamic time history response analysis results, the sum of the sliding areas of each sliding surface of the deep sliding block was calculated. With total sliding surface area percentage ;

[0085] judge Whether it is true or not; among them, The threshold value is set to a range of 0 to 1.

[0086] If so, the gravity dam is within the range of deep sliding stability and has deep anti-sliding stability;

[0087] If not, the gravity dam is at risk of deep anti-sliding instability and failure, requiring reinforcement treatment, and the previous assessment steps should be repeated after reinforcement treatment.

[0088] In this embodiment, the total sliding surface area The calculation formula is:

[0089]

[0090] The sum of the sliding areas of each sliding surface of the deep sliding block. The calculation formula is:

[0091]

[0092] In the formula, This indicates the area affected by each contact point on the contact surface. The area affected by the contact point where sliding failure occurs on the contact surface. This represents the total number of contact point pairs.

[0093] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

[0094] Those skilled in the art will recognize that the embodiments described herein are intended to help the reader understand the principles of the invention, and should be understood that the scope of protection of the invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations based on the technical teachings disclosed in this invention without departing from the spirit of the invention, and these modifications and combinations are still within the scope of protection of this invention.

Claims

1. A method for evaluating the deep sliding stability of a gravity dam in a strong earthquake area with a complex sliding surface, characterized in that, The method comprises the following steps: S1, constructing a finite element analysis model of a dam-foundation system composed of deep sliding blocks formed by weak structural planes inside a foundation rock mass; S2, based on the constructed finite element analysis model of the dam-foundation system, dividing the dam-deep sliding blocks into blocks equal in number to the structural planes of the deep sliding blocks along the vertical direction at each boundary of the structural planes; S3, extracting the dynamic internal force of each time step of the sliding surface of each block, and respectively taking the static load acting on each block as an external force to gradually solve the deep anti-slide stability resistance effect ratio coefficient of the gravity dam at each time step, and draw a time history curve of the deep anti-slide stability resistance effect ratio coefficient; S4, evaluating the deep anti-slide stability of the gravity dam according to the minimum deep anti-slide stability resistance effect ratio coefficient in the time history curve; In the step S3, the method for solving the deep anti-slide stability resistance effect ratio coefficient of the gravity dam is specifically: S31, constructing a calculation formula of the deep anti-slide stability resistance effect ratio coefficient of the whole dam foundation of the gravity dam at each time step based on the resistance function and the effect function of the block i at the time step j; S32, simplifying the calculation formula of the deep anti-slide stability resistance effect ratio coefficient based on the equal deep anti-slide stability resistance effect ratio coefficient of each block; S33, based on the deep anti-slide stability resistance action ratio coefficient calculation formula of each block, N-1 equations about the sum of the shear forces on both sides of the strip i are constructed at each time step j, and the internal force balance formula of the deep anti-slide system of the gravity dam foundation is combined to solve the sum of the shear forces on both sides of each strip i at each time step the sum of the shear forces between the lateral contact surfaces of each strip ; S34, will The formula of the ratio of the deep anti-sliding stability resistance is brought in, and the ratio of the deep anti-sliding stability resistance of each time step j of the gravity dam is solved. In the step S31, the deep anti-sliding stability resistance action ratio coefficient The calculation formula is: wherein, represents the deep anti-slide stability resistance action ratio coefficient of block i at time step j, represents the resistance function of block i at time step j, represents the action effect function of block i at time step j, represents the material performance standard value, represents the material performance sub-item coefficient, represents the geometric parameter standard value, represents the structure importance coefficient, represents the deep anti-slide stability bearing capacity limit state structure coefficient, represents the design condition coefficient, represents the permanent action sub-item coefficient, represents the permanent action standard value, represents the variable action sub-item coefficient, represents the variable action standard value; where the resistance function of strip i at time step j and the action effect function are respectively: wherein, representing a block Shear resistance coefficient of the structural plane of the deep sliding block, representing a block Self-weight of the deep sliding block, representing a block Self-weight of the dam body on the deep sliding block, representing a block Inclination angle of the structural plane of the deep sliding block, representing Time step block Sum of the shear forces on both sides, positive to the upstream, representing known Time step Angle with the horizontal direction, representing a block Water pressure on the structural plane of the deep sliding block, representing a block Resultant force of the side water pressure, representing a block Subjected to other horizontal static loads, representing Time step block Horizontal seismic load on the structural plane of the deep sliding block, representing Time step block Vertical seismic load on the structural plane of the deep sliding block, representing a block Shear resistance cohesion of the structural plane of the deep sliding block, representing a block Area of the structural plane of the deep sliding block.

2. The method for evaluating the stability of a gravity dam against sliding according to claim 1, wherein, In the step S32, the simplified deep anti-slide stability resistance action ratio coefficient The calculation formula is: wherein, , ,…, respectively denote the resistance function of block i~N at time step j, , ,…, denote the action effect function of block i~N at time step j.

3. The method for evaluating the stability of a gravity dam against sliding according to claim 1, wherein, When the minimum deep anti-sliding stability ratio coefficient is greater than 1, the gravity dam is in the deep sliding stability range, and has deep anti-sliding stability. When the minimum deep anti-sliding stability ratio coefficient , the cumulative duration of deep anti-sliding stability ratio coefficient of each time step , the deep anti-sliding stability of gravity dam is analyzed.

4. The method for evaluating the stability of a gravity dam against sliding according to claim 1, wherein, When the cumulative duration of time occurs in the step S4, the gravity dam is out of the deep sliding stable range, the deep sliding stability of the medium gravity dam is further evaluated through the nonlinear time-history response analysis considering the indirect contact nonlinearity among the dam body, the deep sliding block and the foundation. ​ When it appears Cumulative duration With total duration percentage Less than At that time, the gravity dam is within the deep sliding stability range and has deep anti-sliding stability; When it appears Cumulative duration With total duration percentage Greater than At that time, the gravity dam was outside the deep sliding stability range. Considering the nonlinearity of the contact between the dam body, the deep sliding block, and the foundation, the deep anti-sliding stability of the gravity dam was further evaluated through nonlinear time history response analysis. wherein, and are both set constants less than 1.

5. The method for evaluating the stability of a gravity dam against sliding according to claim 4, wherein, The method for further evaluating the deep anti-slide stability of the gravity dam is specifically: For the finite element analysis model of the dam-foundation system, a contact model is used to consider the nonlinearity between the dam, the deep sliding blocks and the foundation, and a nonlinear dynamic time history response analysis is performed considering the radiation damping foundation effect; According to the nonlinear dynamic time-history response analysis result, the sum of the sliding areas of each sliding surface of the deep sliding block body is counted The ratio of the total sliding surface area The ratio ; determining whether the condition is met; wherein, is a set threshold value; If yes, the gravity dam is within the deep sliding stability range and has deep anti-slide stability; If no, the gravity dam has a risk of deep anti-slide instability and failure, and needs to be strengthened.

6. The method for evaluating the stability of a gravity dam against sliding according to claim 5, wherein, the total sliding surface area The formula for calculating the total sliding surface area is: The sum of the sliding areas of the sliding surfaces of the deep sliding block The calculation formula is: wherein represents the contact point influence area on the contact surface, represents the contact point influence area on the contact surface where the sliding failure occurs, represents the total number of contact points.

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