Anti-seismic toughness evaluation method for underground station structure

Abstract

The invention discloses an anti-seismic toughness evaluation method for an underground station structure, and belongs to the technical field of anti-seismic evaluation, and the method comprises the steps: building a finite element model of interaction of a soil-underground station structure, and selecting a natural seismic action as an input working condition; analyzing the vulnerability of the underground station structure based on an incremental dynamic analysis method, and constructing a vulnerability curve of the underground station structure; introducing an economic loss correction coefficient lambda L and a repair time correction coefficient lambda t to respectively determine economic loss rates and repair times of different damage stages, and obtaining an economic loss rate-seismic oscillation intensity curve and a repair time-seismic oscillation intensity curve according to the vulnerability curve; and selecting a proper recovery function to construct a station structure function curve, and calculating the toughness loss of the station structure through integration. According to the method, nonlinear characteristics of a soil body and input site vibration and site randomness are considered, average damage parameters are calculated according to unit area weighting, quantitative analysis is carried out on the structural damage state, and inaccuracy caused by intuitive judgment is overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of seismic evaluation, and particularly relates to a method for evaluating the seismic resilience of an underground station structure. Background Technique

[0002] As an important node of urban rail transit, the post-earthquake recovery ability of a subway station will largely affect the seismic ability of the entire urban rail transit. Since the underground structure is completely buried in soil and water, compared with the ground structure, its post-earthquake repair has the characteristics of great difficulty, long time and high cost. Therefore, it is necessary to quantitatively evaluate the seismic resilience of the underground station structure.

[0003] However, the current research on resilience technology is still in its infancy, and the seismic resilience evaluation system of building structures is mostly established based on the repair experience of superstructures, and is mostly a relatively rough qualitative research. For underground structures, the resilience evaluation system established based on superstructures is still used, without considering the differences in economic losses and repair time caused by the special location selection of underground structures, and cannot reflect the post-earthquake repair characteristics of underground structures. Summary of the Invention

[0004] Technical problems to be solved: Aiming at the problems that the existing resilience evaluation system fails to consider the great difficulty, long time and high cost of post-earthquake repair of underground structures, the present invention provides a method for evaluating the seismic resilience of an underground station structure. This method focuses on the finite element model of soil-structure interaction, adopts the incremental dynamic analysis (IDA) method, introduces the economic loss and repair time correction coefficients, constructs a functional curve and calculates the resilience loss through integration, emphasizing the quantitative evaluation of the economic loss rate and repair time.

[0005] Technical solution: A method for evaluating the seismic resilience of an underground station structure according to the present invention, the evaluation method includes the following steps: Step 1: Establish a finite element model of soil-underground station structure interaction: Considering the nonlinear characteristics of soil and boundary effects, 20 natural ground motions are selected as seismic input conditions; Step 2: Conduct vulnerability analysis of the underground station structure based on the incremental dynamic analysis method: Assume that the structural damage measure DM and the ground motion intensity measure IM follow a double logarithmic linear distribution, and the structural damage measure DM is determined based on the inter-story drift ratio IDR, and a vulnerability curve is constructed using a lognormal distribution; Step 3: Introduce the economic loss correction coefficient λ L and the repair time correction coefficient λ t Determine the economic loss rate and repair time of the underground station structure in different damage states, and combine the vulnerability curve of the underground station structure in Step 2 to obtain the economic loss rate-ground motion intensity PGA curve and the repair time-ground motion intensity PGA curve; Step 4: Select a suitable recovery function to construct the functional curve of the underground station structure, and integrate the functional curve to obtain the toughness loss - ground motion intensity PGA curve of the underground station structure; Step 5: Extract the toughness loss of the underground station structure corresponding to different ground motion intensities based on the calculation results, and evaluate the seismic toughness of the underground station structure accordingly.

[0006] Preferably, in Step 1, the finite element model is established using ABAQUS finite element software; considering the randomness of ground motion, the original peak values of the 20 selected natural ground motions conform to a normal distribution, and the average peak ground motion intensity is 0.47g; the natural ground motions are selected from the Pacific Earthquake Engineering Research (PEER) database in the United States, and 15 ground motions with different peak intensities are generated by amplitude modulation for each natural ground motion, and 300 seismic working conditions are generated for each finite element model; a static - dynamic coupling boundary is used to eliminate the boundary effect of the finite element model.

[0007] Preferably, the calculation formula for the double - logarithmic linear relationship between the structural damage measure DM and the ground motion intensity measure IM in Step 2 is as follows: ; where: a and b are fitting parameters; The vulnerability curve is described by a log - normal distribution function, and its calculation formula is as follows: ; where: P(DS|IM) is the conditional probability of exceeding DM given IM; Φ(·) is the standard normal cumulative distribution function; X is the ground motion intensity measure; μ is the central value of X corresponding to DM; β C is the uncertainty of the bearing capacity of the underground structure; β DS is the uncertainty brought by the definition of the structural damage measure; β D is the average standard deviation of the IM - DM double - logarithmic regression analysis, and its calculation formula is as follows: ; where: N is the total number of non - linear dynamic time - history analyses.

[0008] Preferably, the specific method for determining the structural damage measure DM in Step 2 is: using the average seismic damage value DCPs of the underground station structure calculated by weighting according to the element area to quantitatively describe the damage state of the underground station structure; when the number of calculation cases is too large, program acceleration is used to process a large amount of numerical simulation data, and a random forest model is used to predict the seismic performance level of the underground station structure; the calculation formula for the average seismic damage value DCPs is as follows: ; ; where: Dt,avg , D c,avg are respectively the average seismic tensile damage value and the average seismic compressive damage value of the vulnerable section; i represents the i-th element in the section, and n is the total number of elements in the section; A i and A are respectively the area of the i-th element in the section and the total area of the elements in the section; d t,i and d c,i are respectively the seismic tensile damage factor d t and the seismic compressive damage factor d c of the i-th element in the section.

[0009] Preferably, the calculation of the economic loss rate in step three should be based on a basic assumption: the damage state of each component is always consistent with the damage state of the overall structure; (I) The calculation formula for the economic loss under different damage states is as follows: ; In the formula: j is the component category; i is the damage state, which is divided into 4 levels, namely slight damage, moderate damage, severe damage, and collapse; C (i, j) is the sum of the costs of the j-th type of component in the damage state i, calculated according to the current quota; η 1(i, j) is the damage coefficient of the j-th type of component in the damage state i; λ L, i is the economic loss correction coefficient introduced considering the complexity of the repair work of the underground structure under different damage states; (II) The ratio of the economic loss L loss, i of each damage state of the underground station structure to the construction cost L is defined as the economic loss coefficient μ i , and its calculation formula is as follows: ; (III) The expected value of the economic loss based on the vulnerability probability is the predicted economic loss rate under different seismic ground motion intensities, and its calculation formula is as follows: .

[0010] Preferably, the specific value standard of the damage coefficient η 1(i, j) in step three (I) is as follows: Concrete column: slight 0.1, moderate 0.2, severe 0.5, collapse 1; Concrete beam: slight 0.1, moderate 0.2, severe 0.6, collapse 1; Concrete side wall: slight 0.1, moderate 0.2, severe 0.75, collapse 1; Concrete floor slab: slight 0.1, moderate 0.2, severe 0.75, collapse 1.

[0011] Preferably, in step three (I), λ under different damage states L, i takes the following values respectively: mild 1.0, moderate 2.0, severe 2.0, collapse 2.0.

[0012] Preferably, the calculation of the repair time in step three should be based on three basic assumptions: ① The damage state of each component is always consistent with the damage state of the overall structure; ② The number of workers reaches the maximum capacity of the station, and the working ability of the workers has no significant difference; ③ The columns and side walls in the underground station structure can be repaired simultaneously; (IV) When the overall structure of the underground station is in the damage state i, the calculation formula for the repair man-hours of the kth floor is as follows: ; In the formula: Q (i, j, k) is the repair man-hours of the jth type of component in the kth floor when in the damage state i; n (i, j, k) is the number of the jth type of component in the kth floor when in the damage state i; ζ T(i) is the reduction coefficient of repair man-hours considering the repair workload of the jth type of earthquake-damaged component. When the number of components n ≤ 10, ζ T(j) = 1 for different components. When the number of components n > 50, ζ T(j) = 0.75, and the intermediate values are calculated by interpolation; λ T(k) is the influence coefficient considering the position k of the earthquake-damaged component in the floor and is taken according to different floor numbers; (V) The calculation formula for the repair time of the k th floor is as follows: ; In the formula: λ t is the correction coefficient of repair time introduced considering the complexity of the underground structure repair work; N k is the maximum number of workers per floor: N k = 0.026A k , where A k is the area of the kth floor; (VI) The final repair time of the subway underground station structure takes the maximum value of each floor: ; (VII) The expected value of the repair time based on the fragility probability is the predicted repair time under different ground motion intensities, and its calculation formula is as follows: .

[0013] Preferably, the specific value standard of the repair man-hours Q (i, j, k) in step three (IV) is as follows: Concrete column: mild 2.6, moderate 6.2, severe 9.4, collapse 27.8; Concrete beam: slight degree 3.8, moderate degree 5.6, severe degree 11.3, collapse 25.0; Concrete side wall: slight degree 4.2, moderate degree 5.3, severe degree 13.9, collapse 30.0; Concrete floor slab: slight degree 4.2, moderate degree 5.3, severe degree 13.9, collapse 30.0.

[0014] Preferably, the calculation formula of the function curve in Step 4 is as follows: ; In the formula: f rec (t, t0, T RE ) is the recovery function, which is defined as a linear, exponential, and triangular recovery function considering different recovery strategies, and its calculation formula is as follows: ; H ( x ) is the Heaviside step function, and its calculation formula is as follows: ; t0 and t1 are the occurrence time of the earthquake disaster and the completion time of repair, respectively; The ductility loss parameter of the underground station structure is defined as the integral of the function curve in the t range from 0 to t 1, and its calculation formula is as follows: .

[0015] Compared with the prior art, the present invention has at least the following prominent advantages.

[0016] The method of the present invention focuses on the finite element model of soil-structure interaction, proposes the treatment of the nonlinear boundary effect of soil and the static-dynamic coupling model, uses the ABAQUS software for modeling, and combines with the PEER ground motion database. The method is standardized and repeatable; the incremental dynamic analysis (IDA) method is combined with the random forest model to predict the seismic performance, improving the calculation efficiency; the economic loss correction coefficient λL and the repair time correction coefficient λt are introduced. The correction coefficients of economic loss and repair time are set based on actual engineering experience and are operable; a functional curve is constructed and the ductility loss is calculated by integration, which is more in line with the actual scenario of the long repair period and high cost of underground structures, and solves the problem that the complexity of underground structure repair (such as earth excavation and road occupation construction) has not been quantified by existing methods. Through new parameters, new models and new methods, the pain points not covered by the existing technology are solved; its core is the quantification of economic and time costs, using the economic loss rate, repair time and structural damage parameter (DCP) as quantification indicators, and using the unit area weighted average damage parameter (DCP) to replace intuitive judgment, improving the objectivity of damage state description. Emphasize the quantitative evaluation of the economic loss rate and repair time. Through quantitative economic and time corrections, it may more accurately reflect the repair difficulty of underground structures and solve the problem that the complexity of underground structure repair has not been fully considered. Through the verification of the DAIKAI station case, the prediction results are in agreement with the actual earthquake damage data (economic loss rate 141.8%, repair time 210.7 days), proving the reliability of the method; through quantitative evaluation, it provides more accurate support for the seismic design, reinforcement and emergency decision-making of underground stations. Description of the Drawings

[0017] Figure 1 It is a schematic diagram of the implementation process of the method of the present invention; Figure 2 is Figure 1 a schematic diagram of the construction steps of Step 1 in Figure 3 is Figure 1 a schematic diagram of the construction steps of Step 2 in Figure 4 is Figure 1 a schematic diagram of the construction steps of Step 3 in Figure 5 is Figure 1 a schematic diagram of the construction steps of Step 4 in Figure 6 It is a comparison chart of the economic loss rate of the DAIKAI station in the embodiment of the present invention; Figure 7 It is a comparison chart of the repair time of the DAIKAI station in the embodiment of the present invention; Figure 8 It is a post-earthquake functional curve chart of the DAIKAI station in the embodiment of the present invention. Detailed Embodiments

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will describe the technical solutions of the embodiments of the present invention in conjunction with the attached Figures 1 to 8 The technical solutions of the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the described embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art belong to the scope of protection of the present invention.

[0019] Embodiment 1: As Figures 1 to 5 shown, the present invention discloses a method for evaluating the seismic resilience of an underground station structure, and the evaluation method includes the following steps: (1) Establish a finite element model of the soil-underground station structure interaction: Considering the nonlinear characteristics of the soil and boundary effects, 20 natural ground motions are selected as seismic input conditions; the finite element model is established using ABAQUS finite element software; considering the randomness of ground motions, the original peak values of the 20 selected natural ground motions conform to a normal distribution, and the average peak ground motion intensity is 0.47g; the natural ground motions are selected from the Pacific Earthquake Engineering Research (PEER) database in the United States, and each ground motion generates 15 ground motions with different peak intensities through amplitude modulation, and 300 seismic conditions are generated for each finite element model; static-dynamic coupling boundaries are used to eliminate the boundary effects of the finite element model.

[0020] (2) Conduct vulnerability analysis of the underground station structure based on the incremental dynamic analysis method: Assume that the structural damage measure DM and the ground motion intensity measure IM follow a double logarithmic linear distribution, and the structural damage measure DM is determined based on the inter-story drift ratio IDR, and a vulnerability curve is constructed using a lognormal distribution. The specific steps are as follows: (1) The calculation formula for the double logarithmic linear relationship between the structural damage measure DM and the ground motion intensity measure IM is as follows: ; In the formula: a and b are fitting parameters, and the values of the fitting parameters a and b can be determined based on the double logarithmic linear relationship between the structural damage measure DM and the ground motion intensity measure IM.

[0021] (2) The vulnerability curve is described by a lognormal distribution function, and its calculation formula is as follows: ; In the formula: P(DS|IM) is the conditional probability of exceeding DM under a given IM; Φ(·) is the standard normal cumulative distribution function; X is the ground motion intensity measure; μ is the central value of X corresponding to DM; β C is the uncertainty of the bearing capacity of the underground structure; β DS is the uncertainty brought by the definition of the structural damage measure; β DThe average standard deviation for the IM-DM double logarithmic regression analysis, and its calculation formula is as follows: ; In the formula: N is the total number of times of the nonlinear dynamic time history analysis.

[0022] (3) The specific method for determining the structural damage measure DM is as follows: The average seismic damage value DCPs of the underground station structure calculated by weighting according to the element area is used to quantitatively describe the damage state of the underground station structure; when the number of calculation conditions is too large, the program is used to accelerate the processing of a large number of numerical simulation data, and at the same time, the random forest model is used to predict the seismic performance level of the underground station structure; the calculation formula of the average seismic damage value DCPs is as follows: ; ; In the formula: D t,avg , D c,avg are the average seismic tensile damage value and the average seismic compressive damage value of the vulnerable section respectively; i represents the i-th element in the section, and n is the total number of elements in the section; A i and A are the area of the i-th element in the section and the total area of the elements in the section respectively; d t,i and d c,i are the seismic tensile damage factor d t and the seismic compressive damage factor d c of the i-th element in the section respectively.

[0023] (III) Introducing the economic loss correction coefficient λ L and the repair time correction coefficient λ t Determine the economic loss rate and repair time of the underground station structure in different damage states, and combine with the vulnerability curve of the underground station structure in step two to obtain the economic loss rate - ground motion intensity PGA curve and the repair time - ground motion intensity PGA curve.

[0024] (1) The calculation of the economic loss rate should be based on a basic assumption: the damage state of each component is always consistent with the damage state of the overall structure. The specific implementation steps are as follows: (I) The calculation formula of the economic loss in different damage states is as follows: ; In the formula: j is the component category; i is the damage state, which is divided into 4 levels, namely slight damage, moderate damage, severe damage and collapse; C (i, j) is the sum of the costs of the j-th type of component in the damage state i, calculated according to the current quota; η 1(i, j) is the damage coefficient of the j-th type of component in the damage state i, and the damage coefficient η 1(i, j)The specific value criteria are as follows: for concrete columns: slight damage 0.1, moderate damage 0.2, severe damage 0.5, collapse 1; for concrete beams: slight damage 0.1, moderate damage 0.2, severe damage 0.6, collapse 1; for concrete side walls: slight damage 0.1, moderate damage 0.2, severe damage 0.75, collapse 1; for concrete floors: slight damage 0.1, moderate damage 0.2, severe damage 0.75, collapse 1. λ L, i is the economic loss correction coefficient introduced considering the complexity of the repair work of the underground structure in different damage states. The values of λ L, i in different damage states are respectively: slight damage 1.0, moderate damage 2.0, severe damage 2.0, collapse 2.0.

[0025] (II) The economic loss L loss, i of each damage state of the underground station structure to the construction cost L is defined as the economic loss coefficient μ i , and its calculation formula is as follows: .

[0026] (III) The expected value of the economic loss based on the fragility probability is the predicted economic loss rate under different ground motion intensities, and its calculation formula is as follows: .

[0027] (2) The calculation of the repair time should be based on three basic assumptions: ① The damage state of each component is always consistent with the damage state of the overall structure; ② The number of workers reaches the maximum capacity of the station, and there is no significant difference in the working ability of the workers; ③ The columns and side walls in the underground station structure can be repaired simultaneously.

[0028] (IV) When the overall structure of the underground station is in the damage state i, the calculation formula for the repair working hours of the kth floor is as follows: ; Where: Q (i, j, k) is the repair working hours of the jth type of component in the kth floor when it is in the damage state i, and the specific value criteria of Q (i, j, k) are as follows: for concrete columns: slight damage 2.6, moderate damage 6.2, severe damage 9.4, collapse 27.8; for concrete beams: slight damage 3.8, moderate damage 5.6, severe damage 11.3, collapse 25.0; for concrete side walls: slight damage 4.2, moderate damage 5.3, severe damage 13.9, collapse 30.0; for concrete floors: slight damage 4.2, moderate damage 5.3, severe damage 13.9, collapse 30.0. n (i, j, k) is the number of the jth type of component in the kth floor when it is in the damage state i; ζ T(i) is the repair working hours reduction coefficient considering the repair workload of the jth damaged component. When the number of components n ≤ 10, ζ T(j) = 1 for different components. When the number of components n > 50, ζ T(j)= 0.75, and the intermediate quantity is calculated by interpolation; λ T(k) The influence coefficient considering the damaged components at the floor position k is taken according to different numbers of floors.

[0029] (V) The k formula for the repair time of the k-th floor is as follows: ; In the formula: λ t is the repair time correction coefficient introduced to consider the complexity of the repair work of the underground structure; N k is the maximum number of workers per floor: N k = 0.026A k , A k is the area of the k-th floor; (VI) The final repair time of the subway underground station structure takes the maximum value of each floor: ; (VII) The expected value of the repair time based on the vulnerability probability is the predicted repair time under different ground motion intensities, and its calculation formula is as follows: .

[0030] (4) Select a suitable recovery function to construct the functional curve of the underground station structure, and integrate the functional curve to obtain the ductility loss - ground motion intensity PGA curve of the underground station structure.

[0031] (1) The calculation formula of the functional curve is as follows: ; In the formula: f rec (t, t0, T RE ) is the recovery function, which is defined as a linear, exponential, and triangular recovery function considering different recovery strategies, and its calculation formula is as follows: ; (2) H(x) is the Heaviside step function, and its calculation formula is as follows: .

[0032] (3) t0 and t1 are the earthquake disaster occurrence time and the repair completion time respectively.

[0033] (4) The ductility loss parameter of the underground station structure is defined as the integral of the functional curve in the t range from 0 to t 1, and its calculation formula is as follows: .

[0034] (5) Extract the ductility losses of the underground station structure corresponding to different earthquake motion intensities based on the calculation results, and evaluate the seismic ductility of the underground station structure accordingly.

[0035] As Figures 6 to 8 shown, taking the DAIKAI Station as an example, the ductility evaluation method proposed in the present invention is verified. Using the embodiment of the present invention, the post-earthquake economic loss rate of the DAIKAI Station is predicted to be 141.8%, and the repair time is 210.7 days. Moreover, under the condition of PGA = 0.85g, the structural function of the station is completely lost, verifying the accuracy of the present invention.

[0036] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for evaluating the seismic toughness of underground station structures, characterized in that: The evaluation method comprises the following steps: Step 1: Establish a finite element model of soil-underground station structure interaction: Considering the nonlinear characteristics of soil and boundary effects, 20 natural ground motions are selected as earthquake input conditions; Step 2: Perform vulnerability analysis of underground station structures based on the incremental dynamic analysis method: Assume that the structural damage measure DM and the earthquake intensity measure IM obey a double logarithmic linear distribution, and the structural damage measure DM is determined based on the inter-story displacement angle IDR, and use the log-normal distribution to construct the vulnerability curve; Step 3: Introduce the economic loss correction factor λ L and the repair time correction factor λ t Determine the economic loss rate and repair time of underground station structures in different damage states, and combine the underground station structure fragility curve in step 2 to obtain the economic loss rate-seismic intensity PGA curve and the repair time-seismic intensity PGA curve; Step 4: Select a suitable recovery function to construct the function curve of the underground station structure, and integrate the function curve to obtain the toughness loss-seismic intensity PGA curve of the underground station structure; Step 5: Based on the calculation results, extract the toughness loss of the underground station structure corresponding to different seismic motion intensities, so as to evaluate the seismic toughness of the underground station structure.

2. The method for evaluating seismic toughness of underground station structures according to claim 1, characterized in that: In step 1, the finite element model is established using ABAQUS finite element software; considering the randomness of seismic motion, the original peak values ​​of the 20 selected natural seismic motions conform to the normal distribution, and the average seismic motion intensity peak value is 0.47g; the natural seismic motion is selected from the Pacific Earthquake Engineering Research PEER database of the United States, and each seismic motion is generated by amplitude modulation to generate 15 seismic motions with different peak intensities, and each finite element model generates 300 earthquake conditions; the static-dynamic coupling boundary is used to eliminate the boundary effect of the finite element model.

3. The method for evaluating seismic toughness of underground station structures according to claim 1, characterized in that: The calculation formula of the double logarithmic linear relationship between the structural damage measure DM and the earthquake intensity measure IM in step 2 is as follows: ； Where: a , b is the fitting parameter; The vulnerability curve is described by the log-normal distribution function, and its calculation formula is as follows: ； Where: P(DS|IM) is the conditional probability of exceeding DM given IM; Φ(·) is the standard normal cumulative distribution function; X is the ground motion intensity measure; μ is the central value of X corresponding to DM; β C is the uncertainty of underground structure bearing capacity; β DS Uncertainty caused by the definition of structural damage measurement; β D is the mean standard deviation of the IM-DM double logarithmic regression analysis, and its calculation formula is as follows: ； Where: N is the total number of nonlinear dynamic time history analysis.

4. The method for evaluating seismic toughness of underground station structures according to claim 3, characterized in that: The specific method for determining the structural damage measure DM in step 2 is: using the average seismic damage value DCPs of the underground station structure calculated based on the unit area weight to quantitatively describe the damage state of the underground station structure; when the number of calculation conditions is too large, a program is used to accelerate the processing of a large amount of numerical simulation data, and a random forest model is used to predict the seismic performance level of the underground station structure; the calculation formula of the average seismic damage value DCPs is as follows: ； ； Where: D t,avg , D c,avg are the average tensile damage value of the vulnerable section and the average compressive damage value of the vulnerable section respectively; i represents the i-th unit in the section, n is the total number of units in the section; A i and A are the area of ​​the ith unit in the cross section and the total area of ​​the units in the cross section respectively; d t,i and d c,i are the seismic tensile damage factor d of the i-th element in the section. t and earthquake compressive damage factor d c .

5. The method for evaluating seismic toughness of underground station structures according to claim 1, characterized in that: The calculation of the economic loss rate in step 3 should be based on a basic assumption: the damage state of each component is always consistent with the damage state of the overall structure; (I) The calculation formula for economic losses under different damage states is as follows: ； Where: j is the component type; i is the damage state, which is divided into 4 levels, namely slight damage, moderate damage, severe damage and collapse; C (i, j) is the sum of the costs of the jth type of components in damage state i, calculated according to the current quota; η 1(i, j) is the damage coefficient of the j-th type component when it is in damage state i; λ L, i The economic loss correction factor introduced to consider the complexity of repair work for underground structures in different damage states; (II) Economic losses L of underground station structures in various damage states loss, i The ratio of the cost of construction L is defined as the economic loss coefficient μ i , and its calculation formula is as follows: ； (III) The expected value of economic loss based on vulnerability probability is the predicted economic loss rate under different earthquake intensities, and its calculation formula is as follows: 。 6. The method for evaluating seismic toughness of underground station structures according to claim 5, characterized in that: Damage coefficient η in step 3 (I) 1(i, j) The specific value standard is: Concrete columns: mild 0.1, moderate 0.2, severe 0.5, collapse 1; Concrete beam: mild 0.1, moderate 0.2, severe 0.6, collapse 1; Concrete side wall: mild 0.1, moderate 0.2, severe 0.75, collapse 1; Concrete floor: mild 0.1, moderate 0.2, severe 0.75, collapse 1.

7. The method for evaluating seismic toughness of underground station structures according to claim 6, characterized in that: λ under different damage states in step 3 (I) L, i The values ​​are: mild 1.0, moderate 2.0, severe 2.0, collapse 2.

0.

8. The method for evaluating seismic toughness of underground station structures according to claim 5, characterized in that: The calculation of the repair time in step 3 should be based on three basic assumptions: ① The damage state of each component is always consistent with the damage state of the overall structure; ② The number of workers reaches the maximum capacity of the station and there is no significant difference in the working ability of the workers; ③The central columns and side walls of underground station structures can be repaired at the same time; (IV) When the overall structure of the underground station is in damage state i, the calculation formula for the repair man-hour of the kth floor is as follows: ； Where: Q (i, j, k) is the repair time of the jth type component when the kth layer is in damage state i; n (i, j, k) is the number of components of type j when the kth layer is in damage state i; ζ T(i) In order to consider the reduction factor of the repair work time for the jth type of earthquake damaged component repair project, when the number of components n≤10, different components are taken as ζ T(j) =1, when the number of components n>50, we take ζ T(j) =0.75, and intermediate quantities are calculated by interpolation; T(k) In order to consider the influence coefficient of the earthquake-damaged component at the floor position k, the value is taken according to the number of floors; (V) Chapter k The calculation formula for the repair time of a layer is as follows: ； Where: t The repair time correction factor introduced to take into account the complexity of underground structure repair work; N k Maximum worker capacity for a single layer: N k =0.026A k , A k is the area of ​​the kth layer; (VI) The final repair time of the subway underground station structure is the maximum value of each layer: ； (VII) The expected value of the repair time based on the vulnerability probability is the predicted repair time under different earthquake intensities, and its calculation formula is as follows: 。 9. The method for evaluating seismic toughness of underground station structures according to claim 8, characterized in that: Step 3 (IV) Repair time Q (i, j, k) The specific value standard is: Concrete columns: mild 2.6, moderate 6.2, severe 9.4, collapsed 27.8; Concrete beams: mild 3.8, moderate 5.6, severe 11.3, collapsed 25.0; Concrete side walls: mild 4.2, moderate 5.3, severe 13.9, collapsed 30.0; Concrete floor: mild 4.2, moderate 5.3, severe 13.9, collapse 30.

0.

10. The method for evaluating seismic toughness of underground station structures according to claim 8, characterized in that: The calculation formula of the function curve in step 4 is as follows: ； Where: f rec (t, t0, T RE ) is the recovery function, and different recovery strategies are defined as linear, exponential and triangular recovery functions. The calculation formula is as follows: ； H ( x ) is the Heaviside step function, and its calculation formula is as follows: ； t0 and t1 are the time when the earthquake disaster occurred and the time when the repair was completed, respectively; The toughness loss parameter of underground station structure is defined as t 0 to t The integral of the interval 1 is calculated as follows: 。

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