Anti-seismic safety evaluation method

Abstract

The invention provides an anti-seismic safety evaluation method, relates to the field of anti-seismic safety evaluation of high arch dams, and establishes a finite element mesh model which is more in line with the real situation and comprehensively considers coupling of dam body damage and potential sliding block sliding instability damage of a dam abutment. A concrete damage evolution curve is obtained based on a concrete material dynamic mechanical test, the maximum credible seismic oscillation is scaled to a plurality of seismic oscillation intensity levels according to a certain proportion by adopting an incremental dynamic analysis method, a series of nonlinear dynamic response analysis under different overload coefficients is carried out, and the maximum credible seismic oscillation intensity level is calculated according to an analysis result. An anti-seismic performance evaluation index which is easier for actual engineering monitoring and can comprehensively characterize coupling of two failure modes is provided, a fitting curve of relative residual displacement along with the change of an overload coefficient is established, and a method for quantitatively dividing different failure levels is provided. The development of high arch dam-foundation system anti-seismic safety evaluation from only consideration of a single failure mode to comprehensive consideration of coupling of multiple failure modes is developed and promoted.

Description

Technical Field

[0001] The invention belongs to the field of seismic safety evaluation of high arch dams, and in particular relates to a seismic safety evaluation method. Background Art

[0002] In recent years, a series of 300m-high arch dams have been planned, under construction, or built in earthquake-prone areas. Compared with 100-meter-high dams, their seismic performance may be fundamentally different from that of 100-meter-high dams, from quantitative change to qualitative change. In addition, the complexity of the arch dam structure itself and the continuous improvement of the seismic fortification intensity of dam sites in strong earthquake zones have made the seismic safety issue of high arch dams increasingly prominent.

[0003] Existing earthquake damage examples show that under strong earthquakes, concrete dams may suffer from both dam body damage and cracking failure and dam abutment sliding instability failure. These two failure modes are mutually influential and inseparable, and are also key issues in the seismic design and seismic safety analysis of high dams. However, the current specifications and most of the existing research have carried out seismic safety evaluation of dams based on dam body strength damage or dam abutment instability damage respectively, and have not yet considered the mutual coupling of the two failure modes, making it difficult to fully reflect the actual seismic performance of high arch dams under strong earthquakes. At the same time, since the seismic performance evaluation indicators and corresponding quantitative evaluation criteria of dams are very complex and are still in the exploratory stage, there is no unified and recognized quantitative criterion. Based on the high arch dam-foundation multi-coupling system, the present invention proposes a seismic safety evaluation index and method that can comprehensively couple the dam body strength damage and dam abutment instability damage. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a seismic safety evaluation method, which solves the problem that there is no unified performance evaluation index and corresponding quantitative evaluation criteria for the evaluation of the seismic safety of dams under the maximum credible earthquake in existing studies.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: a seismic safety evaluation method, comprising the following steps:

[0006] According to the actual structure of the high arch dam and the characteristics of topographic and geological conditions, a three-dimensional finite element mesh model of the high arch dam-foundation system including the transverse joints of the dam body, the contact surface between the dam body and the foundation, and the potential sliding blocks of the dam abutment was constructed.

[0007] Obtain concrete damage evolution curve based on dynamic mechanical test of concrete materials;

[0008] The incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels;

[0009] The three-dimensional finite element mesh model of the high arch dam-foundation system, the concrete damage evolution curve and the earthquake motion under different overload coefficients are used as inputs. The nonlinear dynamic response analysis program is used to comprehensively consider the nonlinearity of the dam concrete material and the contact nonlinearity of the dam transverse joints, the dam foundation interface and the sliding surface of the potential sliding block of the dam abutment. The nonlinear dynamic response analysis under different overload coefficients is carried out.

[0010] Based on the analysis results of nonlinear dynamic response, the relative residual displacement index is obtained by extracting the post-earthquake residual displacement of the crown beam dam top and bottom.

[0011] A scatter plot of the relative residual displacement index changing with the overload coefficient is constructed, and a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting at each inflection point of the mutation;

[0012] According to the inflection point of the relative residual displacement-overload coefficient fitting curve, the high arch dam-foundation system is divided into different damage levels. Based on the division results, a seismic safety evaluation is carried out to obtain the seismic safety margin of the high arch dam-foundation system.

[0013] Furthermore, the concrete damage evolution curve is obtained based on the dynamic mechanical test of concrete material, which is specifically:

[0014] The strain ε corresponding to the initial peak stress is solved using the following formula: p :

[0015]

[0016] Among them, σ p represents the peak stress, E0 represents the initial elastic modulus;

[0017] The unloading gap width vector C is calculated using the following formula: u :

[0018] C u =[c up ,c u1 ,c u2 ,...,c un ]=[ε p ,ε1,ε2,...,ε n' ]×L

[0019] ε'=[ε p ,ε1,ε2,...,ε n' ]

[0020] Where, L represents the extensometer gauge length, c up represents the peak unloading gap width, c un represents the nth unloading gap width, ε' represents the total strain vector, ε n' represents the n'th total strain;

[0021] The unloading gap width c in the full process loading and unloading test of the concrete specimen u and residual seam width c res The relationship is statistically analyzed and the regression equation is obtained:

[0022]

[0023] Among them, m i represents the regression analysis constant, n represents a positive integer, i represents a positive integer from 0 to n, Indicates c u ith power of

[0024] Using the regression equation, the residual seam width vector C is calculated. res :

[0025]

[0026] Among them, c resp represents the peak residual crack width, c resn” Indicates the n”th residual seam width;

[0027] According to the residual gap width vector C res , the residual strain vector ε' is calculated using the following formula: res :

[0028] ε' res =[ε resp ,ε res1 ,ε res2 ,...,ε resn”' ]=[c resp ,c res1 ,c res2 ,...,c resn” ] / L;

[0029] Among them, ε resp represents the peak residual strain, ε resn”' represents the n''th residual strain;

[0030] According to the measured stress-strain curve of the whole process of monotonic loading or cyclic loading, the analytical equation of the tensile decline curve is constructed by using test data fitting and statistical methods:

[0031]

[0032] Among them, σ represents stress, k and λ represent fitting constants;

[0033] Using the analytical equation, solve for the stress vector σ':

[0034]

[0035] Among them, σ n”” Respectively represent the nth stress;

[0036] In response to concrete tensile damage, based on the analytical equation, the residual strain vector ε' res and stress vector σ', we get the damage factor vector;

[0037] According to the total strain vector and the elastic strain vector, the cracking strain vector is obtained;

[0038] Based on the cracking strain vector, the cracking displacement vector is calculated to complete the acquisition of the concrete damage evolution curve, which is a cracking displacement-stress curve and a cracking displacement-damage factor curve.

[0039] Furthermore, the expression of the damage factor is as follows:

[0040]

[0041] Among them, d tp represents the peak damage factor, d tn””' Indicates the n'th damage factor.

[0042] Furthermore, the cracking displacement vector u c The expression is as follows:

[0043]

[0044] u c =[ε cp ,ε c1 ,ε c2 ,ε c3 ,...,ε cn””' ]×L

[0045] Among them, ε cp Peak cracking strain, ε cn””” Represents the n””th cracking strain.

[0046] Furthermore, the incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels, which are specifically:

[0047] The incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels using the following formula:

[0048] λ i+1 =λ i +Δλ i

[0049] Among them, λ i+1represents the scaling factor of the i+1th ground motion intensity level, λ i represents the scaling factor of the i-th ground motion intensity level, Δλ i Indicates the scaling step size of the i-th ground motion intensity level.

[0050] Furthermore, the expression of the relative residual displacement index is as follows:

[0051] u r =u top -u bottom

[0052] Among them, u r Represents the relative residual displacement index, u top represents the residual displacement of the dam crest after earthquake, u bottom It represents the residual displacement of the dam bottom after an earthquake.

[0053] Furthermore, the scatter plot of the relative residual displacement index changing with the overload coefficient is constructed, and a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting at each inflection point of the mutation, which is specifically:

[0054] A1. Construct a scatter plot of the relative residual displacement index versus the overload coefficient;

[0055] A2. At each mutation inflection point, the relative residual displacement-overload coefficient fitting curve is constructed by linear fitting using the following formula:

[0056]

[0057] Among them, y represents the residual displacement, x represents the overload coefficient, a1, a2, a j , b1, b2 and b j' All represent linear constants, and j” represents a positive integer;

[0058] A3. Determine whether the fitting goodness and slope of the relative residual displacement-overload coefficient fitting curve meet the following requirements. If so, complete the construction of the relative residual displacement-overload coefficient fitting curve. Otherwise, return to A1 and re-fit:

[0059] (R 2 >α)∩((a j+1 -a j ) / a j |>β)

[0060] Among them, R 2 represents goodness of fit, α represents a constant, β represents a constant, a j and a j+1 They represent the linear constants of the j-th and j+1-th segments respectively.

[0061] Beneficial effects of the present invention:

[0062] (1) The present invention constructs a finite element mesh model of a high arch dam-foundation system that is more in line with the actual situation and comprehensively considers the damage to the dam body and the coupled sliding instability of the dam body and part of the foundation, and proposes a method for obtaining the concrete damage evolution curve based on the dynamic mechanical test of concrete materials. The present invention overcomes the shortcomings of the traditional solution based on multiple plasticity theory assumptions, and can more reasonably reflect the actual working properties of the dam concrete material, laying a foundation for the subsequent seismic safety evaluation of the dam.

[0063] (2) The present invention proposes an evaluation index for the seismic safety of a high arch dam-foundation system that is easier to monitor in actual projects and can comprehensively characterize the coupling between dam body damage and dam shoulder sliding instability, proposes a method for quantitatively dividing different damage levels, and provides a method for evaluating the seismic safety of a high arch dam-foundation system that comprehensively considers strength and stability. This solves the problem that there is no unified performance evaluation index and corresponding quantitative evaluation criteria for the evaluation of the seismic safety of dams under the maximum credible earthquake in existing studies. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 The present invention is a flow chart of the method.

[0065] Figure 2 It is a schematic diagram of the three-dimensional finite element mesh model of the high arch dam-foundation system in this embodiment.

[0066] Figure 3 It is a schematic diagram of the three-dimensional finite element mesh model of the dam body and the potential sliding block on the dam abutment in this embodiment.

[0067] Figure 4 Schematic diagram of the time history curve of the Yokogawa-direction seismic acceleration in this embodiment.

[0068] Figure 5 Schematic diagram of the time history curve of the earthquake acceleration along the river in this embodiment.

[0069] Figure 6 Schematic diagram of vertical earthquake acceleration time history curve in this embodiment.

[0070] Figure 7 Schematic diagram of the dynamic damage softening curve of concrete in this embodiment.

[0071] Figure 8 Schematic diagram of the concrete dynamic damage curve in this embodiment.

[0072] Fig. 9 Schematic diagram of the residual displacement of the dam crest relative to the dam bottom under different overload coefficients in this embodiment. DETAILED DESCRIPTION

[0073] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0074] Example

[0075] In view of the fact that the current seismic codes and existing related studies on high arch dams are based on a single consideration of the dam body strength failure or the dam abutment slider sliding instability failure to carry out seismic safety evaluation of the high arch dam-foundation system, and there is no unified and recognized high arch dam-foundation system seismic safety evaluation index and corresponding quantitative evaluation criteria, the present invention provides a high arch dam-foundation system seismic safety evaluation method that comprehensively considers strength and stability, such as Figure 1 As shown, a seismic safety evaluation method is implemented as follows:

[0076] S1. According to the actual structure of the high arch dam and the characteristics of the topographic and geological conditions, a three-dimensional finite element mesh model of the high arch dam-foundation system including the transverse joints of the dam body, the contact joints between the dam body and the foundation, and the potential sliding blocks of the dam abutment is constructed;

[0077] In this embodiment, in order to make the simulation results more accurate, the finite element mesh size of the dam body is generally controlled to be around 2m.

[0078] S2. Based on the dynamic mechanical test of concrete materials, the concrete damage evolution curve is obtained, which is as follows:

[0079] B1. Use the following formula to solve the strain ε corresponding to the initial peak stress p :

[0080]

[0081] Among them, σ p represents the peak stress, E0 represents the initial elastic modulus;

[0082] B2. Use the following formula to calculate the unloading gap width vector C u :

[0083] C u =[c up ,c u1 ,c u2 ,...,c un ]=[ε p ,ε1,ε2,...,ε n' ]×L(2)

[0084] ε'=[ε p,ε1,ε2,...,ε n' ] (3)

[0085] Where, L represents the extensometer gauge length, c up represents the peak unloading gap width, c un represents the nth unloading gap width, ε' represents the total strain vector, ε n' represents the n'th total strain;

[0086] B3. Unloading joint width c in the whole process loading and unloading test of concrete specimens u and residual seam width c res The relationship is statistically analyzed and the regression equation is obtained:

[0087]

[0088] Among them, m i represents the regression analysis constant, n represents a positive integer, i represents a positive integer from 0 to n, Indicates c u ith power of

[0089] B4. Using the regression equation, calculate the residual seam width vector C res :

[0090]

[0091] Among them, c resp represents the peak residual crack width, c resn” Indicates the n”th residual seam width;

[0092] B5. According to the residual seam width vector C res , the residual strain vector ε' is calculated using the following formula: res :

[0093] ε' res =[ε resp ,ε res1 ,ε res2 ,...,ε resn”' ]=[c resp ,c res1 ,c res2 ,...,c resn” ] / L (6);

[0094] Among them, ε resp represents the peak residual strain, ε resn”' represents the n''th residual strain;

[0095] B6. According to the measured stress-strain curve of the whole process of monotonic loading or cyclic loading, the analytical equation of the tensile decline curve is constructed by using test data fitting and statistical methods:

[0096]

[0097] Among them, σ represents stress, k and λ represent fitting constants;

[0098] B7. Use the analytical equation to solve the stress vector σ':

[0099]

[0100] Among them, σ n”” Respectively represent the nth stress;

[0101] B8. After concrete is subjected to tensile damage, the residual strain vector ε' is calculated based on the analytical equation. res and stress vector σ', we get the damage factor vector d t :

[0102]

[0103] Among them, d tp represents the peak damage factor, d tn””' represents the n''th damage factor;

[0104] B9. Obtain the cracking strain vector according to the total strain vector and the elastic strain vector;

[0105] B10. Based on the cracking strain vector, the cracking displacement vector is calculated to obtain the concrete damage evolution curve. The concrete damage evolution curve is a cracking displacement-stress curve and a cracking displacement-damage factor curve. The cracking displacement vector u c The expression is as follows:

[0106]

[0107] u c =[ε cp ,ε c1 ,ε c2 ,ε c3 ,...,ε cn””' ]×L(11)

[0108] Among them, ε cp Peak cracking strain, ε cn””” represents the n”””th cracking strain;

[0109] S3, using incremental dynamic analysis method to scale the maximum credible ground motion to multiple ground motion intensity levels;

[0110] In this embodiment, the scaling factor λ i That is the overload coefficient, as shown in formula (12):

[0111] λ i+1 =λ i +Δλ i (12)

[0112] Among them, λ i+1 represents the scaling factor of the i+1th ground motion intensity level, λ i represents the scaling factor of the i-th ground motion intensity level, Δλ i Indicates the scaling step size of the i-th ground motion intensity level.

[0113] In this embodiment, Δλ i It can be equal scaling step length or non-equal scaling step length. If it is equal scaling step length, if the scaling step length is too large, some important structural changes may be ignored. If the scaling step length is too small, a lot of time history analysis may be required. If it is non-equal scaling step length, the scaling step length can be reduced at the stage where the structural performance changes significantly, and vice versa. Therefore, the scaling principle can be equal step scaling or non-equal step scaling according to the needs.

[0114] S4. Taking the three-dimensional finite element mesh model of the high arch dam-foundation system, the concrete damage evolution curve and the earthquake motion under different overload coefficients as input, the nonlinear dynamic response analysis under different overload coefficients is carried out by using a nonlinear dynamic response analysis program that comprehensively considers the nonlinearity of the dam concrete material and the contact nonlinearity of the dam transverse joints, the interface between the dam foundation and the sliding surface of the potential sliding block of the dam abutment;

[0115] In this embodiment, the nonlinear dynamic response analysis program includes a nonlinear dynamic response analysis program of material nonlinearity and contact nonlinearity.

[0116] S5. Based on the analysis results of nonlinear dynamic response, the relative residual displacement index is obtained by extracting the post-seismic residual displacement of the crown beam dam top and dam bottom;

[0117] In this embodiment, based on the nonlinear dynamic response analysis results, the post-seismic residual displacements of the crown beam dam top and dam bottom are extracted, and then the post-seismic residual displacement of the dam top u top Subtract the residual displacement u of the dam bottom after earthquake bottom Get the relative residual displacement index u r , as shown in formula (13). The relative residual displacement index u r It is easier to monitor in actual projects, and can comprehensively characterize the coupling between dam strength failure and dam abutment sliding instability failure:

[0118] u r =u top -u bottom (13).

[0119] S6. Construct a scatter plot of the relative residual displacement index changing with the overload coefficient, and construct a relative residual displacement-overload coefficient fitting curve by linear fitting at each inflection point of the mutation, which is specifically:

[0120] A1. Construct a scatter plot of the relative residual displacement index versus the overload coefficient;

[0121] A2. At the inflection point of each mutation, a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting;

[0122] A3. Determine whether the goodness of fit and slope of the relative residual displacement-overload coefficient fitting curve meet the following requirements. If so, complete the construction of the relative residual displacement-overload coefficient fitting curve. Otherwise, return to A1 and perform fitting again.

[0123] In this embodiment, the obtained relative residual displacement index is used to establish a scatter plot of the index changing with the overload coefficient, and then a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting (such as formula (14)) at each sudden inflection point, wherein the goodness of fit and slope of the fitting curve should meet the requirements of formula (15). If the requirements are not met, it means that the discreteness of the original data and the fitting curve is large, the linear fit is poor, or the slope of the segmented fitting curve does not change significantly, and the selection of the inflection point is unreasonable. Therefore, if the requirements of formula (15) are not met, re-fitting should be performed:

[0124]

[0125] Among them, y represents the residual displacement, x represents the overload coefficient, a1, a2, a j , b1, b2 and b j' Both represent linear constants, and j” represents a positive integer.

[0126] (R 2 >α)∩((a j+1 -a j ) / a j |>β)(15)

[0127] Among them, R 2 represents goodness of fit, α represents a constant, a j and a j+1 They represent the linear constants of the j-th and j+1-th segments respectively, β represents a constant, and generally β≥0.

[0128] S7. According to the inflection point of the relative residual displacement-overload coefficient fitting curve, the high arch dam-foundation system is divided into different damage levels. Based on the division results, a seismic safety evaluation is carried out to obtain the seismic safety margin of the high arch dam-foundation system.

[0129] In this embodiment, the high arch dam-foundation system can be divided into different damage levels, such as slight damage, moderate damage and severe damage, according to the inflection points of the fitting curve of the relative residual displacement changing with the overload coefficient, and then the seismic safety evaluation can be carried out according to the damage of the high arch dam-foundation system.

[0130] In summary, the present invention aims at the current specifications and related studies that only consider the single dam body strength failure or the sliding instability failure of the dam shoulder slider, establishes a finite element mesh model that is more in line with the actual situation and comprehensively considers the coupling of dam body damage and the sliding instability failure of the potential sliding block of the dam shoulder, provides a seismic safety evaluation method for the high arch dam-foundation system that comprehensively considers strength and stability, obtains the concrete damage evolution curve based on the dynamic mechanical test of concrete materials, adopts the incremental dynamic analysis method to scale the maximum credible seismic motion to multiple seismic motion intensity levels according to a certain proportion, and then carries out a series of nonlinear dynamic response analyses under different overload factors, and according to the analysis results, proposes a seismic performance evaluation index that is easier to monitor in actual engineering and can comprehensively characterize the coupling of two failure modes, namely, the post-seismic residual displacement of the dam top relative to the dam bottom, establishes a fitting curve of the relative residual displacement changing with the overload coefficient, divides different damage levels according to the inflection points obtained by the sudden change of the fitting curve, carries out the seismic safety evaluation of the high arch dam-foundation system, and promotes the development of the seismic safety evaluation of the high arch dam-foundation system from only considering a single failure mode to comprehensively considering the coupling of multiple failure modes.

[0131] In order to further illustrate the present invention, the following is further described with an engineering case:

[0132] Taking a high arch dam as an example, considering the actual topographic and geological conditions of the dam site and the zoning of various bedrock materials, a three-dimensional finite element analysis model of the high arch dam-foundation coupling system was constructed, which can more realistically and comprehensively reflect the damage and failure of the dam body and the overall sliding instability of the dam body and part of the foundation. The model includes the dam body, the potential sliding blocks of the left and right bank abutments, and the foundation bedrock. Figure 2-Figure 3 The total number of nodes in the finite element model is 3548298, and the total number of elements is 3329118. The unit size of the dam body is about 2m, and the maximum dam height is 285.5m.

[0133] The material parameters of the dam concrete used in the calculation are: tensile strength of 3.66MPa, static elastic modulus of 24GPa, Poisson's ratio of 0.167, and density of 2400kg / m 3 The dynamic elastic modulus of the dam body is 1.5 times the static elastic modulus. The dynamic damage evolution relationship of the dam body concrete is as follows: Figure 7 and Figure 8 As shown in the figure, the material parameters of the potential sliding blocks on the left and right dam shoulders are: elastic modulus is 11.5 GPa, density is 2850 kg / m 3, Poisson's ratio is 0.25; the material parameters of bedrock are: elastic modulus is 16.5GPa, Poisson's ratio is 0.2, and density is 2850kg / m 3 ; The values ​​of the joint surface parameters in the model are: the friction coefficient of the dam foundation interface is 1.1, the cohesion is 1.1MPa, the tensile strength is 2.4MPa, the friction coefficient of the bottom sliding surface of the potential sliding block on the left bank dam abutment is 0.435, the cohesion is 0.09MPa, the friction coefficient of the bottom sliding surface of the potential sliding block on the right bank dam abutment is 0.5, the cohesion is 0.17MPa, the friction coefficient of the side sliding surface of the potential sliding block on the left and right bank dam abutments is 1.2, and the cohesion is 1.8MPa.

[0134] The static loads acting on the dam body in the calculation and analysis include: the deadweight of the dam body, the hydrostatic pressure on the upstream and downstream surfaces, the silt pressure and the uplift pressure. The hydrodynamic pressure is applied in the form of Westergaard added mass, and the peak acceleration of the bedrock is 0.432g. Its acceleration time history curve is as follows: Figure 4 , Figure 5 and Figure 6 shown.

[0135] The incremental dynamic analysis method is used to scale the maximum credible earthquake to different seismic intensity levels with non-uniform scaling steps to carry out nonlinear dynamic response analysis under different overload coefficients, where the overload coefficients are 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.3, 1.4, 1.5, 1.6, 1.8, 2.0, 2.2 and 2.4 respectively. Based on the analysis results, the fitting curve of the post-seismic residual displacement of the dam crest relative to the dam bottom along the river with different overload coefficients is established, as shown in Fig. 9 As shown, if α = 0.9, β = 0, the goodness of fit R1 2 =0.9885, The relative slopes |(a2-a1) / a1|=2.19, |(a3-a2) / a2|=3.37, both meet the fitting requirements. Therefore, with the increase of the overload coefficient, the residual displacement has two sudden inflection points. According to the changes in its inflection points, it can be divided into three damage levels, namely slight damage, moderate damage, and severe damage. In summary, under the maximum credible earthquake action (peak acceleration of 0.432g), the high arch dam-foundation system has not been seriously damaged, and there is still a certain safety reserve.

[0136] The above-mentioned examples only express the implementation methods of the present invention, but it cannot be understood that there is no limitation on the patent scope of the present invention. It should be noted that for those skilled in the art, any equivalent replacement or change based on the technical solution and inventive concept of the present invention should be included in the protection scope of the present invention.

Claims

1. A seismic safety evaluation method, characterized in that: The following steps are involved: According to the actual structure of the high arch dam and the characteristics of topographic and geological conditions, a three-dimensional finite element mesh model of the high arch dam-foundation system including the transverse joints of the dam body, the contact surface between the dam body and the foundation, and the potential sliding blocks of the dam abutment was constructed. Obtain concrete damage evolution curve based on dynamic mechanical test of concrete materials; The incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels; The three-dimensional finite element mesh model of the high arch dam-foundation system, the concrete damage evolution curve and the earthquake motion under different overload coefficients are used as inputs. The nonlinear dynamic response analysis program is used to comprehensively consider the nonlinearity of the dam concrete material and the contact nonlinearity of the dam transverse joints, the dam foundation interface and the sliding surface of the potential sliding block of the dam abutment. The nonlinear dynamic response analysis under different overload coefficients is carried out. Based on the analysis results of nonlinear dynamic response, the relative residual displacement index is obtained by extracting the post-seismic residual displacement of the crown beam dam top and bottom. A scatter plot of the relative residual displacement index changing with the overload coefficient is constructed, and a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting at each inflection point of the mutation; According to the inflection point of the relative residual displacement-overload coefficient fitting curve, the high arch dam-foundation system is divided into different damage levels. Based on the division results, a seismic safety evaluation is carried out to obtain the seismic safety margin of the high arch dam-foundation system.

2. The seismic safety evaluation method according to claim 1, characterized in that: The concrete damage evolution curve is obtained based on the dynamic mechanical test of concrete material, which is specifically: The strain ε corresponding to the initial peak stress is solved using the following formula: p : Among them, σ p represents the peak stress, E0 represents the initial elastic modulus; The unloading gap width vector C is calculated using the following formula: u : C u =[c up ,c u1 ,c u2 ,...,c un ]=[e p ,e1,e2,...,e n' ]×L e'=[e p ,e1,e2,...,e n' ] Where, L represents the extensometer gauge length, c up represents the peak unloading gap width, c un represents the nth unloading gap width, ε' represents the total strain vector, ε n' represents the n'th total strain; The unloading gap width c in the full process loading and unloading test of the concrete specimen u and residual seam width c res The relationship is statistically analyzed and the regression equation is obtained: Among them, m i represents the regression analysis constant, n represents a positive integer, i represents a positive integer from 0 to n, Indicates c u ith power of Using the regression equation, the residual seam width vector C is calculated. res : Among them, c resp represents the peak residual crack width, c resn” Indicates the nth residual seam width; According to the residual gap width vector C res , the residual strain vector ε' is calculated using the following formula: res : e' res =[e resp ,he res1 ,he res2 ,...,eh resn”' ]=[c resp ,c res1 ,c res2 ,...,c resn” ] / L; Among them, ε resp represents the peak residual strain, ε resn”' represents the n''th residual strain; According to the measured stress-strain curve of the whole process of monotonic loading or cyclic loading, the analytical equation of the tensile decline curve is constructed by using test data fitting and statistical methods: Among them, σ represents stress, k and λ represent fitting constants; Using the analytical equation, solve for the stress vector σ': Among them, σ n”” Respectively represent the nth stress; In response to concrete tensile damage, based on the analytical equation, the residual strain vector ε' res and stress vector σ', we get the damage factor vector; According to the total strain vector and the elastic strain vector, the cracking strain vector is obtained; Based on the cracking strain vector, the cracking displacement vector is calculated to complete the acquisition of the concrete damage evolution curve, which is a cracking displacement-stress curve and a cracking displacement-damage factor curve.

3. The seismic safety evaluation method according to claim 2, characterized in that: The damage factor vector d t The expression is as follows: Among them, d tp represents the peak damage factor, d tn””' Indicates the n'th damage factor.

4. The seismic safety evaluation method according to claim 2, characterized in that: The cracking displacement vector u c The expression is as follows: you c =[e cp ,he c1 ,he c2 ,he c3 ,...,eh cn””' ]×L Among them, ε cp Peak cracking strain, ε cn””” Represents the n””th cracking strain.

5. The seismic safety evaluation method according to claim 1, characterized in that: The incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels, which are specifically: The incremental dynamic analysis method is used to scale the maximum credible ground motion to multiple ground motion intensity levels using the following formula: l i+1 =λ i +Dl i Among them, λ i+1 represents the scaling factor of the i+1th ground motion intensity level, λ i represents the scaling factor of the i-th ground motion intensity level, Δλ i Indicates the scaling step size of the i-th ground motion intensity level.

6. The seismic safety evaluation method according to claim 1, characterized in that: The expression of the relative residual displacement index is as follows: in r =in top -in bottom Among them, u r Represents the relative residual displacement index, u top represents the residual displacement of the dam crest after earthquake, u bottom It represents the residual displacement of the dam bottom after an earthquake.

7. The seismic safety evaluation method according to claim 1, characterized in that: The scatter plot of the relative residual displacement index changing with the overload coefficient is constructed, and a relative residual displacement-overload coefficient fitting curve is constructed by linear fitting at the inflection point of each mutation, which is specifically: A1. Construct a scatter plot of the relative residual displacement index versus the overload coefficient; A2. At each mutation inflection point, the relative residual displacement-overload coefficient fitting curve is constructed by linear fitting using the following formula: Among them, y represents the residual displacement, x represents the overload coefficient, a1, a2, a j , b1, b2 and b j' All represent linear constants, and j” represents a positive integer; A3. Determine whether the fitting goodness and slope of the relative residual displacement-overload coefficient fitting curve meet the following requirements. If so, complete the construction of the relative residual displacement-overload coefficient fitting curve. Otherwise, return to A1 and re-fit: (R 2 >a)∩((a j+1 -a j ) / a j |>b) Among them, R 2 represents goodness of fit, α represents a constant, β represents a constant, a j and a j+1 Represent the linear constants of the j-th and j+1-th segments respectively.

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