Comprehensive anti-seismic toughness index of underground station and evaluation method of comprehensive anti-seismic toughness index

Abstract

The invention provides an underground station comprehensive anti-seismic toughness index and an evaluation method thereof. The comprehensive anti-seismic toughness index is obtained by multiplying the average function, the recovery time and the economic loss factor, the influence of the repairing method, the repairing sequence and the repairing strategy on the anti-seismic performance of the structure is considered, and the capacity of the underground station structure for resisting earthquake disasters and rapidly and economically recovering to the target performance is reflected. The comprehensive anti-seismic toughness index evaluation process comprises the steps of determining basic information of a station, establishing a station numerical model, analyzing structural dynamic response, analyzing component damage consequences, calculating structural toughness factors and evaluating structural anti-seismic toughness. The logic is clear, the consideration is comprehensive, and the operation is simple. According to the invention, engineers can be guided to perform underground station shock resistance toughness evaluation grading and toughness improvement work.

Description

Technical Field

[0001] The present application belongs to the technical field of seismic resilience assessment, and specifically relates to a comprehensive resilience index of an underground station and an assessment method thereof. Background Art

[0002] As an emerging concept, focusing on the ability of structures to resist disasters and repair quickly, seismic resilience has become a new development direction in the seismic design of modern buildings. Subway stations are important hubs connecting the above-ground and underground transportation networks, so their seismic resilience is an important guarantee for the safe operation of the city's transportation lifeline. At present, the seismic resilience assessment method of underground stations mainly refers to the above-ground structure, or adopts a quantitative resilience assessment method based on the function curve, or adopts a multi-index resilience assessment method based on repair time, repair cost, and casualties. However, the quantitative resilience assessment method based on the function curve does not fully consider the impact of the repair method and strategy, and cannot reflect the real recovery process; the multi-index resilience evaluation method does not reflect the specific structural function loss, and the mathematical relationship between the specific resilience value and the multiple indicators has not been established, which is not conducive to resilience analysis and comparison. In addition, the seismic resilience assessment method of the above-ground structure does not fully consider the structural and functional characteristics of the underground structure.

[0003] Therefore, it is necessary to provide a comprehensive seismic resilience index for underground stations and an evaluation method thereof to solve the problems raised in the above background technology. Summary of the invention

[0004] The present application provides an underground station comprehensive seismic resilience index and an evaluation method thereof. The comprehensive seismic resilience of the underground station is evaluated by multiplying the average function, recovery time, and economic loss factor to form a single index. The influence of the repair method, repair sequence, and repair strategy on the seismic resilience of the structure is considered, and it reflects the ability of the underground station structure to resist earthquake disasters and quickly and economically recover to the target performance. It helps industry workers to compare and grade the seismic resilience of underground station structures, and provides a theoretical basis for the future improvement of the seismic resilience and design of underground stations.

[0005] In order to solve the above technical problems, the technical solution of this application is:

[0006] A comprehensive seismic toughness index for underground stations, characterized in that the comprehensive seismic toughness index is composed of average function, recovery time, and economic loss factor, and the calculation formula is as follows:

[0007]

[0008] Where R is the comprehensive seismic toughness index of the station, is the average functional factor, (1-C tot / C control ) is the recovery time factor, (1-Ttot / T control ) is the economic loss factor, C tot is the total economic tons, C control In order to control economic losses, the cost of station reconstruction is generally taken as T tot is the total recovery time, T control In order to control the recovery time, the reconstruction time is generally taken.

[0009] Specifically, when any of the average functional factor, recovery time factor, and economic loss factor is less than 0, the structure is considered to have no resilience. When the comprehensive seismic resilience index is between 0 and 0.22, the structural resilience rating is considered to be "poor"; when the comprehensive seismic resilience index is between 0.22 and 0.42, the structural resilience rating is considered to be "average"; when the comprehensive seismic resilience index is between 0.42 and 0.73, the structural resilience rating is considered to be "good"; when the comprehensive seismic resilience index is between 0.73 and 1.00, the structural resilience rating is considered to be "excellent".

[0010]

[0011] Preferably, the average function factor of the station is a dimensionless parameter, which is the ratio of the area enclosed by the structural function curve and the coordinate axis to the total recovery time. The average function can be quantified by the four properties of the structure (robustness, rapidity, improvement, and optimization), and the formula is as follows:

[0012]

[0013] Where: R ro is robustness, R ra For rapidity, R up To improve the performance, R op is the optimization, T0 is the station post-earthquake stagnation time, T C Time for station construction.

[0014] Specifically, the robustness calculation formula is as follows:

[0015]

[0016] Where: w i is the weight coefficient of the i-th type component, D i The functional loss of the component.

[0017] Furthermore, the component weight coefficient and function loss calculation formula are as follows:

[0018]

[0019]

[0020] Where: P, Ki，p 、N i are the number of floors of the station, the number of type i components on the pth floor, and the number of damage states of type i components. i，p is the weight coefficient of the i-th type component under the p-th floor, w i，p，k is the weight coefficient of the kth component of the i-th type component in the p-th floor; D i，p，k is the functional loss of the kth component of the i-th type component under the p-th floor, d i，j is the functional loss of the i-th type component under the j-damage state, P i，p，k，j EDP ​​is the probability that the kth component of the i-th type component on the p-th floor will experience the j-damage state. i，j is the median value of the engineering demand parameter of the i-th type of station component under the j-damage state, EDP i，，min and EDP i，max It is the lower limit of the engineering requirement parameter corresponding to the beginning of functional damage and complete damage of the i-th type component of the station.

[0021] Specifically, the rapidity calculation formula is as follows:

[0022]

[0023] Where: T R is the post-earthquake repair time of the station, which takes into account whether the station can provide the maximum number of repair workers and the situation of repairing while the station is in operation. The calculation formula is as follows

[0024]

[0025] Where: W i is the repair time of the i-th type of components in the station, W i，j is the repair time of the i-th type component of the station under the j-damage state, and λ is the parameter of whether the structure can provide the demand of repair workers in time, which is mainly related to the transportation conditions, funding level, labor resources, etc. around the structure. max L is the maximum number of workers that can be provided for structural repair during shutdown and repair. actual is the actual station function loss, L thereshold It is the functional loss threshold corresponding to the time when the station is shut down for repair, and is related to the defense level of the station structure.

[0026] Specifically, the calculation formula for lift is as follows:

[0027]

[0028] Where: QT is the restoration target performance of the station, and Q0 is the initial performance of the station.

[0029] According to different repair targets, the improvement is divided into four categories: basic improvement, medium improvement, complete improvement and excess improvement. Their definitions and calculation formulas are shown in the following table:

[0030]

[0031] Specifically, the optimization calculation formula is as follows:

[0032]

[0033] Where Q(t) is the functional recovery curve of the repair process, which is composed of multiple continuous step straight lines. Each step straight line segment represents a functional change within a repair work. The calculation formula for the repair time and recovery function of each stage is as follows:

[0034]

[0035]

[0036] Where: T i is the repair time of the i-th type component, QE is the residual performance of the station, J0 represents different levels of improvement, and J0=2, 3, and 4 represent full improvement, medium improvement, and basic improvement, respectively.

[0037] Preferably, the station recovery time factor is generally determined by the difference between 1 and rapidity.

[0038] Preferably, the economic loss factor of the station is the difference between 1 and the ratio of total economic damage to controlled economic loss. The total economic loss includes direct economic losses caused by repair costs and casualties, as well as indirect economic losses. The calculation formula is as follows:

[0039] C tot =C D +C I =C D +γC D

[0040]

[0041] Where: C D Including direct economic losses caused by restoration activities and casualties, C I is the indirect economic loss caused by the structural earthquake damage repair, γ is the coefficient of the indirect economic coefficient, which is related to the local economic level, the importance of the station, etc., C i，j is the repair cost of the i-th type component in the j-damage state, Z0 is the total number of people in the underground station structure, U is the level of structural casualties, including slight injury, moderate injury, severe injury and death, P uIt represents the probability of casualties of u degree in underground structures, which is related to the residual performance of the structure, etc. u It represents the economic loss under the casualty level u, which is related to the local economic level.

[0042]

[0043] An evaluation method for the above-mentioned comprehensive seismic toughness index of an underground station comprises the following steps:

[0044] Step 1: Determine the basic information of the underground station, including geometric material information, seismic fortification level, component vulnerability model, consequence function, repair strategy, etc.;

[0045] Step 2: Establish a numerical model of the underground station, determine the seismic hazard, and conduct structural dynamic analysis;

[0046] Step 3: Extract the engineering requirement parameters of each station component, including the inter-story displacement angle and floor acceleration;

[0047] Step 4: Determine the probability of each level of damage to the component based on the component engineering requirement parameters and the fragility curve, and then determine the corresponding repair time, repair cost, functional loss, etc. for each damage level of the component based on the consequence function, so as to obtain the expected repair time, expected repair cost and expected functional loss of the component by weighted summation.

[0048] Step 5: Obtain the functional loss of the entire station by weighted summation of component functional losses. Determine the repair time and corresponding recovery function of each repair work of the station according to the structural repair strategy to obtain the functional recovery curve of the entire station. Determine the post-earthquake-repair total functional curve of the station structure by combining the functional loss and functional recovery curves, and then determine the robustness, rapidity, improvement and optimization of the overall station structure.

[0049] Step 6: Calculate the average function of the station based on the robustness, rapidity, improvement and optimization of the station. Calculate the recovery time based on the downtime and repair time. Calculate the total economic loss of the station based on the repair costs and direct and indirect economic losses caused by casualties. Finally, obtain the comprehensive seismic resilience index of the underground station and conduct a resilience rating.

[0050] The optimized station components include structural components such as central columns, side walls, beams, entrances and exits, and non-structural components such as elevators, stairs, ceilings, cooling towers, fans, and pipelines. The repair strategy for underground stations is to repair entrances and exits and stairs first, and then repair structural components and non-structural components. Among them, structural components and non-structural components are determined according to the importance coefficient of the components.

[0051] The beneficial effects of the present invention are as follows:

[0052] 1. The average function quantification method of underground stations based on robustness, rapidity, improvement and optimization reflects the structural and functional characteristics of underground stations, quantifies the transmission of component functional damage to structural functional loss, considers the flexibility of repair target performance and repair methods, reproduces the actual repair process of underground stations, and reflects the impact of repair strategies and sequences on the average function of stations.

[0053] 2. The comprehensive seismic resilience index can take into account the contribution of average function, recovery time and economic loss to the seismic resilience of the station, reflecting the ability of the underground station structure to resist earthquake disasters and quickly and economically recover to the target performance.

[0054] 3. The comprehensive seismic toughness index is used as a single index and gives different levels of seismic toughness index ranges, which is convenient for toughness comparison and classification.

[0055] 4. The evaluation method of comprehensive seismic resilience indicators of underground stations has clear logic, comprehensive considerations, and simple operation, which is conducive to guiding engineers to carry out seismic resilience assessment and resilience improvement design work for underground stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 Schematic diagram showing average functions and comprehensive resilience indicators of underground stations;

[0057] Figure 2 It represents a schematic diagram of the comprehensive resilience index evaluation process;

[0058] Figure 3 A diagram showing the engineering requirements parameters of a station;

[0059] Figure 4 A diagram showing the consequences of component damage at a certain station;

[0060] Figure 5 A diagram showing the influence of station enhancement on seismic toughness;

[0061] Figure 6 Diagram showing the influence of station downtime and the number of repair workers on seismic resilience. DETAILED DESCRIPTION

[0062] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0063] like Figure 1As shown, the comprehensive seismic resilience of underground stations provided in this embodiment is composed of an average functional factor, a recovery time factor, and an economic loss factor. Among them, the average functional factor is quantified by the four structural properties (robustness, rapidity, improvement, and optimization). The recovery time factor includes stagnation time and repair time. The economic loss factor includes direct economic losses and indirect economic losses.

[0064] It is worth noting that the robustness in the average functional factor is obtained by weighted summation of component functional losses, taking into account the transmission of component damage to structural functional losses; the improvement is selected independently by the owner, taking into account the flexibility of the repair target performance and the repair method; the rapidity considers the ratio of recovery time to reconstruction time, reflecting the speed at which the station is repaired to the target performance; the optimization is determined according to the repair time and corresponding recovery function under each repair work, reflecting the actual repair process, and taking into account the impact of the repair sequence and strategy on seismic resilience.

[0065] like Figure 2 As shown in the flow chart, the underground station seismic toughness index evaluation method proposed in this embodiment includes the following steps:

[0066] Step 1: Select a two-story, two-span open-cut station in Changsha. The fragility curve of the structural components is as follows: Figure 3 The vulnerability of non-structural components refers to the "GB / T38591-2020 Building Seismic Resilience Evaluation Standard". The functional loss consequences and casualties consequences of station components are calculated with reference to the corresponding formulas proposed, and the repair time and repair cost consequence functions refer to the "GB / T38591-2020 Building Seismic Resilience Evaluation Standard". In the station repair strategy, the entrances and exits and stairs are repaired first, and then the structural components and non-structural components are repaired. Among them, the structural components and non-structural components are determined according to the importance coefficient of the components.

[0067] Step 2: Establish a three-dimensional solid numerical model of the station in the visualization software STKO of OpenSees. The concrete strength of the central column of the station is C50, the concrete strength of other parts is C35, and the strength of the steel bars of the station is HRB400. The homogeneous soil is considered in the model, and the elastic-plastic constitutive model and octahedral solid elements are used to simulate the soil. The concrete is modeled as an octahedral solid element and simulated by the plastic damage constitutive model, and the steel bars are modeled as fiber beam elements and the stee101 constitutive model is used to simulate their basic behavior. The EL centrol wave is selected from the PEER database, and its peak ground acceleration (PGA) is modulated to the rare earthquake intensities of 7, 8, and 9 degrees to perform nonlinear time history analysis on the station.

[0068] Step 3: Extract the engineering demand parameters of the main components of the station, including the maximum inter-story displacement angle and the peak acceleration of the floor, such as Figure 3 shown.

[0069] Step 4: By summing the repair time, repair cost and functional damage of the component under different damage states, the expected repair time, expected repair cost and expected functional loss of the component are calculated as follows: Figure 4 As shown in the figure, it can be seen that structural components such as central columns and side walls, and non-structural components such as system fans, cooling towers, elevators and ceilings are most vulnerable to earthquake disasters and are in urgent need of repair. These components account for 97.6%, 96.9% and 82.2% of the total functional loss, repair time and economic loss of underground stations respectively.

[0070] Step 5: Combined with the structural repair station repair strategy, the robustness of the station under rare earthquake intensities of 7, 8, and 9 degrees is 83.52%, 64.09%, and 41.73%, the rapidity is 89.7%, 80%, and 73.86%, the improvement is 100%, 100%, 100%, and 100%, and the optimization is 20.45%, 32.66%, and 41.92%.

[0071] Step 6: According to the corresponding formula, the average functions of the station under the rare earthquake intensity of 7, 8 and 9 degrees are 86.89%, 75.82% and 66.16%. The recovery time is 93 days, 181 days and 245 days, and the economic losses are 10.572 million yuan, 40.608 million yuan and 79.242 million yuan, so the comprehensive resilience index is calculated to be 0.70, 0.36 and 0.09, and the ratings are good, fair and poor.

[0072] In this implementation, a parameter analysis was conducted to consider the effects of different lifting properties, stagnation time and repair functions on the seismic toughness of the station. The results are as follows: Figure 5 and Figure 6 As shown. It can be seen that the change of seismic toughness with lifting performance is related to the earthquake intensity. When the earthquake intensity is small, the seismic toughness first decreases and then increases. When the earthquake intensity is large, the better the lifting performance, the smaller the seismic toughness. The longer the stagnation time and the more repair workers there are, the lower the average functional level of the station will be, and the reduction will be smaller. Compared with the number of repair workers, seismic toughness is more sensitive to stagnation time.

[0073] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A comprehensive seismic toughness index for underground stations, characterized in that: The comprehensive seismic toughness index is obtained by multiplying the average function, recovery time, and economic loss factor. The calculation formula is as follows: Where R is the comprehensive seismic toughness index of the station, is the average functional factor, (1-C tot / C control ) is the recovery time factor, (1-T tot / T control ) is the economic loss factor, C tot is the total economic loss, C control In order to control economic losses, the cost of station reconstruction is generally taken as T tot is the total recovery time, T control In order to control the recovery time, the reconstruction time is generally taken.

2. The comprehensive seismic toughness index according to claim 1 is characterized in that: The average function is a dimensionless parameter, which is the ratio of the area enclosed by the structure function curve and the coordinate axis to the recovery time. The average function consists of four properties: robustness, rapidity, improvement, and optimization. Its calculation formula is shown below: Where: R ro is robustness, R ra For rapidity, R up To improve the performance, R op is the optimization, T0 is the station post-earthquake stagnation time, T C Time for station construction. The calculation formulas for the robustness, rapidity, improvement and optimization are as follows: Where: L i is the functional loss of the i-th type component, M is the number of station components, w i is the weight coefficient of the i-th type component, D i is the functional loss of the component, T R is the post-earthquake repair time of the station, QT is the repair target performance of the station, Q0 is the initial performance of the station, and QE is the residual performance of the station.

3. The comprehensive seismic toughness index according to claim 2 is characterized in that: The functional loss of the component in robustness is obtained by summing the functional losses under different damage levels, and the weight coefficient of the component is determined according to the functional loss level of the component. As for the functional loss value of the component under the specified damage state, it is determined according to the median value of the engineering demand parameters under different loss states. The formula is as follows: Where: P, K i，p 、N i are the number of floors of the station, the number of type i components on the pth floor, and the number of damage states of type i components. i，p is the weight coefficient of the i-th type component under the p-th floor, w i，p，k is the weight coefficient of the kth component of the i-th type component in the p-th floor; D i，p，k is the functional loss of the kth component of the i-th type component under the p-th floor, d i，j is the functional loss of the i-th type component under the j-damage state, P i，p，k，j is the probability that the kth component of the i-th type component on the p-th floor will experience the j-damage state.

4. The comprehensive seismic toughness index according to claim 2, characterized in that: The repair time in rapidity is the ratio of the total repair time to the number of repair workers, and the calculation formula is as follows: Where: W i is the repair time of the i-th type of components in the station, W i，j is the repair time of the i-th type component of the station under the j-damage state, and λ is the parameter of whether the structure can provide the demand of repair workers in time, which is mainly related to the transportation conditions, funding level, labor resources, etc. around the structure. max L is the maximum number of workers that can be provided for structural repair during shutdown and repair. actual is the actual station function loss, L thereshold It is the functional loss threshold corresponding to the time when the station is shut down for repair, and is related to the defense level of the station structure.

5. The comprehensive seismic toughness index according to claim 2, characterized in that: There are four types of improvement: basic improvement, medium improvement, complete improvement, and excess improvement. The calculation formula is as follows: Basic Improvement: Medium boost: Fully upgraded: R up =1 Excess increase: A number greater than 1 is determined by the owner.

6. The comprehensive seismic toughness index according to claim 2, characterized in that: The optimization is determined by determining the repair time and corresponding recovery function under each repair work. The repair time of each repair work and the repair function under different improvement goals are calculated as follows: Basic / Medium / Full Boost: Excess promotion: Where: T i is the repair time of the i-th type component, Q E is the residual performance of the station, J0 represents different lifting properties, and J0=2, 3, and 4 represent full lifting, medium lifting, and basic lifting, respectively.

7. The recovery time factor according to claim 1, characterized in that: The station recovery time factor is generally determined by the difference between 1 and rapidity.

8. The economic loss factor according to claim 1, characterized in that The economic loss factor of the station is the difference between 1 and the ratio of total economic loss to controlled economic loss. The total economic loss includes direct economic losses caused by repair costs and casualties, as well as indirect economic losses. The calculation formula is as follows: C tot =C D +γC D Where: C D It includes direct economic losses caused by repair activities and casualties, and γ is the coefficient of indirect economic losses, which is related to the local economic level, the importance of the station, etc. i，j is the repair cost of the i-th type component in the j-th damage state. Z0 is the total number of people in the underground station structure, and U is the graded number of structural casualties, including slight injury, moderate injury, severe injury and death. u It indicates the probability of casualties of u degree in underground structures, which is related to the residual performance of the structure, etc.; C u It represents the economic loss under the casualty level u, which is related to the local economic level.

9. A method for evaluating the comprehensive seismic toughness index of a station according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Determine the basic information of the underground station, including seismic fortification, geometric materials, component vulnerability model, consequence function, repair strategy, etc. Step 2: Establish a numerical model of the station, determine the seismic hazard, and conduct structural dynamic analysis; Step 3: Extract the engineering requirement parameters of each station component, including inter-story displacement angle and floor acceleration Step 4: Determine the probability of each level of damage to the component based on the component engineering requirement parameters and the fragility curve, and then determine the corresponding repair time, repair cost, functional loss, etc. for each damage level of the component based on the consequence function. Step 5: Determine the total post-earthquake repair function curve of the station structure by combining the function loss and function recovery curves, and then determine the robustness, rapidity, improvement and optimization of the overall station structure. Step 6: Calculate the average function, recovery time, and economic loss factor of the station to obtain the final comprehensive seismic resilience index of the station and conduct a resilience rating.

10. The station components according to claim 9 include structural components such as central columns, side walls, beams, entrances and exits, and non-structural components such as elevators, stairs, ceilings, cooling towers, fans, and pipelines. The station repair strategy is to repair the entrances and exits and stairs first, and then repair the structural components and non-structural components. The repair order of the structural components and non-structural components is determined according to the importance coefficient of the components.

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