A full probability risk assessment method for railway route selection scheme crossing seismic fault

Abstract

The present application relates to railway route selection technical field, and relates to a kind of railway route selection scheme across seismic fault's total probability risk assessment method.The assessment method uses Monte Carlo simulation, establishes the total probability risk analysis model suitable for railway route selection design across fault zone, is based on the theory of performance-based earthquake engineering, integrates fault zone displacement probability risk analysis, railway structure object probability vulnerability analysis and railway fault rear probability economic loss analysis, can be combined with fault zone characteristics (position, geometric shape, seismic intensity) The annual exceedance probability of specific displacement value is calculated, the damage state of different railway structure (usually avoid using bridge mode to cross fault zone, therefore, the present application mainly considers the intersection of tunnel, embankment section and fault zone) under the influence of fault displacement is evaluated, simultaneously, total probability risk analysis model across fault zone and cost minimization model form cost-risk net present value model, and construction cost and cross-fault zone risk are simultaneously evaluated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of railway route selection, and particularly relates to a full-probability risk assessment method for railway route selection scheme crossing seismic faults. BACKGROUND

[0002] At present, some railways are planned and constructed in strong earthquake zones. For such key lifeline projects, various seismic activities (such as regional seismic motion, earthquake-induced landslides and active fault zones) will significantly threaten their service performance throughout their life cycle. Therefore, it is crucial to pay attention to seismic risk assessment at the initial stage of railway planning and design to reduce the impact of earthquakes on railway engineering infrastructure.

[0003] Route selection design is the core work of railway planning and design, and its main task is to determine the track geometric line position, infrastructure site selection and structure work point layout. However, due to the wide research area, complex topographic and geological conditions, difficulty in quantifying evaluation indicators and multiple coupled constraint factors, route selection design is also a highly challenging work. The traditional manual design method is time-consuming and laborious, and may ignore a large number of potential high-quality schemes due to limited time and resources. To solve these problems, computer-aided railway line optimization has attracted widespread attention from global researchers.

[0004] However, the risk avoidance research of railway route selection in strong earthquake zones is still in the initial stage, and few studies consider the post-earthquake displacement risk when the railway crosses the active fault zone. Ideally, lifeline projects should avoid active fault zones, but in areas where faults are widely distributed, it is often difficult to achieve, and only reasonable line position and structure form can be used to cross the fault zone, at which time the cross-fault railway line faces the risk of earthquake displacement.

[0005] Therefore, the current railway route selection design research still has deficiencies in cross-fault risk assessment, and it is necessary to establish a cross-fault line risk assessment system. SUMMARY

[0006] The main purpose of the present application is to provide a full-probability risk assessment method for railway route selection scheme crossing seismic faults, which aims to solve the problem that the prior art cannot effectively evaluate the displacement risk when the railway crosses the active fault zone in the strong earthquake zone.

[0007] To achieve the above purpose, the present application provides a full-probability risk assessment method for railway route selection scheme crossing seismic faults, comprising the following steps:

[0008] Step S1, obtaining a railway route selection scheme; obtaining the number M of fault zones contained in each railway route selection scheme; judging the type of each fault zone, the type of the fault zone including a main fault zone and a secondary fault zone;

[0009] Step S2, numbering each fault-line intersection point in the railway route selection scheme , =1,2,3,…,M;

[0010] Step S3, for the first Perform fault zone displacement probability hazard analysis at each fault-line intersection point and generate its displacement hazard curve;

[0011] Step S4: Establish and simulate a full probability risk analysis model for crossing fault zones using Monte Carlo simulation, suitable for railway alignment design. This includes:

[0012] Step S4.1: Initialize the Monte Carlo iteration count. =1 and the series of PGD =1;

[0013] Step S4.2: Determine the displacement input of the main fault zone, specifically: sample the third-level permanent ground displacement PGD exceeding the set probability from the disaster curve obtained in step S3; and then... The fault zone displacement value of the PGD level is input into the probabilistic vulnerability analysis model of railway structures to calculate the probability of the structure being in different damage states.

[0014] The displacement input for determining secondary fault zones specifically involves: searching for existing line-fault zone intersections; calculating and obtaining the average displacements of all secondary fault zones near the main fault zone under three types of earthquakes: frequent, occasional, and rare; and then... The average displacement value of the fracture zone of the PGD level is input into the probabilistic vulnerability analysis model of railway structures to calculate the probability of the structure being in different damage states.

[0015] Step S4.3: Combine the probability of the structure being in different damage states to obtain the probabilistic economic loss analysis after the railway is interrupted. The probabilistic economic loss analysis after the railway is interrupted includes: randomly obtaining the damage ratio and recovery time of the structure according to the probability distribution form, determining the reconstruction length of the line after the interruption and calculating the direct repair loss.

[0016] Step S4.4, take = +1, perform a judgment, if If it is less than or equal to K, then return to step S4.2; if If the count is greater than K, proceed to the next step; K is the maximum count value for the set iteration.

[0017] Step S4.3, take = +1, perform a judgment, if If it is greater than 3, proceed to the next step; if If the value is less than or equal to 3, return to step S4.2;

[0018] Step S5, based on the railway gap probability economic loss analysis of S4, the loss value theoretical year exceedance probability is calculated;

[0019] Step S6, based on the loss value theoretical year exceedance probability, the final year direct loss is estimated;

[0020] Step S7, taking = +1, a judgment is made, if is greater than M, then the next step is entered; if is less than or equal to M, return to step S3;

[0021] Step S8, all line-gap intersection risks are summarized to obtain the total annual loss of all gap intersections along the railway; the cost-risk net present value is calculated based on the total annual loss of all gap intersections along the railway.

[0022] Preferably, the main fault zone and the secondary fault zone each contain normal faults, reverse faults and strike-slip faults.

[0023] Preferably, in step S4.2: three levels of permanent ground displacement PGD with exceedance probabilities of 63% / 10% / 2% in 50 years are sampled from the disaster curve; a value of 1 represents a frequent event, a value of 2 represents an occasional event, a value of 3 represents a rare event; different damage states include no damage, moderate and severe.

[0024] Preferably, the railway structure probability vulnerability analysis model includes the following steps:

[0025] ①, the railway line is divided into three types of structure groups, namely bridges, tunnels and roadbed sections;

[0026] ②, define the damage state when the tunnel and roadbed section cross the active fault zone; take PGD as the earthquake intensity index, and derive the following lognormal distribution vulnerability curve for different structure types and damage states:

[0027] ;

[0028] Wherein: represents the conditional probability that the damage state is greater than when PGD takes ; DS is the damage state, is the index of DS, 0 represents no damage, 1 represents moderate damage, 2 represents severe damage; is the median of the th DS;​ the bias for the nth DS; the specific value taken by the PGD;

[0029] iii. calculating the probability of the structure being in different damage states as follows:

[0030]

[0031]

[0032]

[0033] where: Pn represents the probability of the undamaged state; Pm represents the probability of the moderate damage state; Ps represents the probability of the severe damage state.

[0034] Preferably, the cost-risk net present value is calculated using the following equation: to complete the evaluation of the individual line option:

[0035]

[0036]

[0037]

[0038] where: C represents the construction cost; L represents the total annual losses along the railway line at all fault zone crossings; A represents the series present value factor; r represents the interest rate; t represents the time period considered for the seismic risk assessment; D represents the construction duration of the railway; P represents the lump sum present value factor; t represents the time.

[0039] The technical solution of the present application has the following effects:

[0040] ​​​​​​​The railway route selection scheme across seismic fault full probability risk assessment method disclosed by the application adopts Monte Carlo simulation, establishes a full probability risk analysis model suitable for railway route selection design across fault zones, integrates fault zone displacement probability risk analysis, railway structure probability vulnerability analysis and railway fault zone probability economic loss analysis based on performance-based seismic engineering theory, can calculate the annual exceedance probability of a specific displacement value combined with fault zone characteristics (position, geometric shape, seismic intensity), and evaluate the damage state of different railway structures (bridges are usually not used to cross fault zones, so the application mainly considers the intersection of tunnels, roadbed sections and fault zones) under the influence of fault zone displacement. Meanwhile, the full probability risk analysis model across fault zones is combined with a cost minimization model to form a cost-risk net present value model to simultaneously evaluate construction cost and risk across fault zones. BRIEF DESCRIPTION OF DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, a brief introduction will be given to the drawings needed in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor based on the structures shown in the drawings.

[0042] Figure 1 The schematic diagram of the railway route selection scheme across seismic fault full probability risk assessment method in the embodiments of the present application;

[0043] Figure 2 The schematic diagram of the fault zone type in the embodiments of the present application, wherein (a) represents the fault type divided according to the distance from the epicenter; (b) represents the fault type divided according to the fault mechanism;

[0044] Figure 3 The schematic diagram of the structure vulnerability curve related to permanent ground displacement in the embodiments of the present application;

[0045] Figure 4 The schematic diagram of the line repair length in the embodiments of the present application, wherein (a) represents the schematic diagram of the straight line repair length; (b) represents the schematic diagram of the curved section line repair length;

[0046] Figure 5 The schematic diagram of the annual seismic loss calculation in the embodiments of the present application, wherein (a) represents the fitting P cost (C<c |pgd p ) curve diagram; (b) represents the direct loss exceedance probability P cost (C≥c | pgd p ) curve diagram; (c) represents the annual exceedance probability curve diagram of the fault zone displacement; (d) represents the annual direct loss integral curve diagram.

[0047] The objectives, functional characteristics and advantages of the present application will be further described with reference to the embodiments in combination with the accompanying drawings. DETAILED DESCRIPTION

[0048] The technical solutions in the embodiments of the present application will be apparently and completely described in combination with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative work fall within the protection scope of the present application.

[0049] The present embodiment discloses a full-probability risk assessment method for railway route selection scheme crossing seismic faults, which is specifically shown in Figure 1 , and specifically includes:

[0050] Step S1, obtaining a railway route selection scheme; obtaining the number M of fault zones contained in each railway route selection scheme; judging the types of each fault zone, the types of fault zones including main fault zones and secondary fault zones;

[0051] Step S2, numbering each fault-line intersection point in the railway route selection scheme , =1, 2, 3, …, M;

[0052] Step S3, performing a fault zone displacement probability risk analysis on the th fault-line intersection point to generate its displacement disaster curve;

[0053] Step S4, establishing a full-probability risk analysis model suitable for railway route selection design by using Monte Carlo simulation and performing simulation, which specifically includes:

[0054] Step S4.1, initializing the iteration count of Monte Carlo =1 and the order of PGD =1;

[0055] Step S4.2, determining the displacement input of the main fault zone, which is specifically: sampling the three-level permanent ground displacement PGD exceeding the set probability from the disaster curve obtained in step S3; inputting the fault zone displacement value of the order PGD into the railway structure probability vulnerability analysis model to calculate the probability of the structure being in different damage states;

[0056] Determining the displacement input of the secondary fault zone, which is specifically: searching for the existing line-fault zone intersection points; calculating and obtaining the three average displacements of all secondary fault zones near the main fault zone under the frequent, occasional and rare earthquakes; inputting the fault zone displacement value of the The average displacement value of the fracture zone of the PGD level is input into the probabilistic vulnerability analysis model of railway structures to calculate the probability of the structure being in different damage states.

[0057] Step S4.3: Combine the probability of the structure being in different damage states to obtain the probabilistic economic loss analysis after the railway is interrupted. The probabilistic economic loss analysis after the railway is interrupted includes: randomly obtaining the damage ratio and recovery time of the structure according to the probability distribution form, determining the reconstruction length of the line after the interruption and calculating the direct repair loss.

[0058] Step S4.4, take = +1, perform a judgment, if If it is less than or equal to K, then return to step S4.2; if If the count is greater than K, proceed to the next step; K is the maximum count value for the set iteration.

[0059] Step S4.3, take = +1, perform a judgment, if If it is greater than 3, proceed to the next step; if If the value is less than or equal to 3, return to step S4.2;

[0060] Step S5: Calculate the theoretical annual exceedance probability of the loss value based on the economic loss analysis of the railway failure probability obtained in S4.

[0061] Step S6: Estimate the final annual direct loss based on the theoretical exceedance probability of the loss value;

[0062] Step S7, Take = +1, perform a judgment, if If it is greater than M, proceed to the next step; if If M is less than or equal to M, return to step S3;

[0063] Step S8: Summarize the risks of all line-fault zone intersections to obtain the total annual loss of all fault zone intersections along the railway line; calculate the cost-risk net present value based on the total annual loss of all fault zone intersections along the railway line.

[0064] In this embodiment, as Figure 2 As shown in (a), active fault zones are generally classified into two categories based on their distance from the epicenter: primary fault zones (i.e., the main faults with the largest displacement near the epicenter) and secondary fault zones (secondary faults far from the epicenter but affected by the primary faults). Furthermore, based on different mechanisms of action, primary and secondary fault zones can be further subdivided into normal faults, reverse faults, and strike-slip faults. For detailed classifications, please refer to [link to relevant documentation]. Figure 2 As shown in (b). In subsequent Monte Carlo simulations, different probability models will be used for different types of faults.

[0065] In this embodiment, each fault-line intersection is numbered and a fault displacement probability hazard analysis is performed to provide probability input for Monte Carlo simulation. Initialize count = 1, and perform fault displacement probability hazard analysis. First, determine the specific structure of the first line-fault intersection (counting sequentially from the start to the end of the line), and then assume that the fault is the main fault, perform fault displacement probability hazard analysis to generate its displacement hazard curve.

[0066] The specific method of fault displacement probability hazard analysis is referenced from a simplified but practical fault displacement probability hazard analysis method developed by Melissianos et al. in 2024 based on large-scale statistical analysis, which is used for main fault displacement hazard modeling in the life line design stage ( Melissianos, V.E., Vamvatsikos, D., Danciu, L., Basili, R. (2024). Design displacement for lifelines at fault crossings: the code- based approach for Europe. Bull Earthquake Eng 22, 2677-2720 ), to generate fault displacement probability hazard analysis curves to describe different fault dislocation hazard levels in railway route design.

[0067] For secondary faults, this embodiment refers to the research results of Rodriguez Padilla and Oskin ( Rodriguez Padilla, A. M., Oskin M. E. (2023). Displacement hazard from distributed ruptures in strike-slip earth-quakes, Bull. Seismol. Soc. Am. 113, 2730-2745. ).

[0068] In this embodiment, the displacement input of the main fault is determined. From the generated hazard curve, sample the three-level permanent ground displacement (PGD) with a 63% / 10% / 2% exceedance probability in 50 years, respectively corresponding to the frequent, rare and rare earthquakes defined in the “China Seismic Parameter Zoning Map” (GB 18306-2015). Initialize count = 1. Input the fault displacement value of the first level (1 = frequent, 2 = rare, 3 = rare) PGD into the railway structure probability vulnerability analysis model to calculate the probability of the structure being in different damage states (defined as DS, divided into no damage, moderate damage and severe damage).

[0069] The specific implementation method of railway structure probability vulnerability analysis is as follows:

[0070] ①, The railway line is divided into three types of structure groups, namely bridges, tunnels and roadbed sections (including excavation and filling). Since bridges are highly sensitive to ground motion, it is usually prohibited to cross faults with bridges during railway line design, so this study does not consider the bridge-fault intersection scenario. For tunnels and roadbed sections, the following steps are adopted.

[0071] ②, Define the damage state when the tunnel and roadbed section crosses the active fault. Referring to the “HAZUS” report ( FederalEmergency Management Agency (2024). HAZUS earthquake model technical manual 6.1, Washington DC. ), taking PGD as the seismic intensity index, and for different structure types and damage states, the following lognormal distribution vulnerability curves are derived:

[0072] ;

[0073] wherein: represents the conditional probability of the damage state being greater than when PGD takes ; DS is the damage state, is the index of DS, 0 represents no damage, 1 represents moderate damage, 2 represents severe damage; is the median of the th DS; is the deviation of the th DS; is a specific value taken by PGD. The curve parameters are shown in Table 1:

[0074] Table 1 Vulnerability curve parameters of tunnels and earthwork sections

[0075]

[0076] ③, the probability risk analysis model of the displacement of the fracture zone is used to determine the third-level PGD at the intersection of the line and the fracture zone, which exceeds the probability of 63% / 10% / 2% within 50 years. For a specific PGD value (i.e., the threshold value set ).

[0077] The probability of the structure being in different damage states is calculated.

[0078] The following formula is used to calculate the first probability of the structure being in different DS (as shown in Figure 3 ):

[0079] ;

[0080] ;

[0081] ;

[0082] wherein: represents the probability of the no-damage state; represents the probability of the moderate damage state; represents the probability of the severe damage state.

[0083] In this embodiment, the displacement of the secondary fault zone is determined and incorporated into the Monte Carlo simulation framework. For all secondary fault zones near the main fault zone and intersecting the railway line, the displacement risk is triggered by the activity of the main fault zone. Within a 3km range along the small and large mileage directions from the intersection point, search for other line-fault zone intersection points that exist as secondary fault zones. Then, according to the research results of Rodriguez Padilla and Oskin, the average displacement of the secondary fault zone is calculated using the following formula :

[0084] ;

[0085] wherein: is the distance from the main fault zone to the railway line-secondary fault zone intersection point; β is the average displacement of the main fault zone; is the normalization constant (set to 1m in this embodiment); g is the calibration slope (generally taken as 0.41). Finally, the three average displacements of the secondary fault zones near the main fault zone under frequent, occasional and rare earthquakes are calculated. Finally, the fault zone average displacement value of the first level (1=frequent, 2=occasional, 3=rare) PGD is input into the railway structure probability vulnerability analysis model to calculate the probability of the structure being in different damage states (defined as DS, divided into no damage, moderate damage and severe damage).

[0086] Initialize the Monte Carlo single iteration count =1. Then, perform a Monte Carlo simulation random sampling to generate a uniformly distributed random number ω in [0,1] and compare it with the structure damage state probability to determine the specific damage state (DS).

[0087] In this embodiment, the probability economic loss analysis of railway after-break is performed, specifically:

[0088] According to the probability distribution form, the damage ratio and recovery time of the structure are randomly obtained (as shown in Table 2), and the Figure 4 line after-break reconstruction length is determined and the direct repair loss (L) is calculated. Let = + 1. At this point, one iteration of the inner Monte Carlo simulation is completed.

[0089] The implementation method of the probability economic loss analysis of railway after-break is as follows:

[0090] ​The probability risk analysis model of fault zone displacement can be further associated with the probability of structural damage ratio (the ratio of structural repair cost) and recovery time (the time required for the railway function to fully recover from the fault zone rupture), to build a railway fault probability economic loss analysis model. The damage ratio and recovery time are shown in Table 2. Assuming that the damage ratio is randomly and uniformly distributed, and the recovery time is normally distributed.

[0091] Table 2 Structural damage ratio and repair time information

[0092]

[0093] If the DS, damage ratio (D) and recovery days (T) of the structure are known, the seismic fault zone risk can be converted into annual monetary loss (L) by the following formula, including direct loss (Ld, related to structural repair) and indirect loss (Li, related to railway recovery):

[0094] ;

[0095] Wherein: is the unit structural repair loss; is the length of the line section affected by the fault zone deformation; is the empirical daily income related to the length of railway operation; is the total length of the line. As shown in Figure 4 , the line reconstruction process when the line intersects with the fault zone in two ways (straight line or curve) can be simulated from a geometric point of view, which can be divided into two cases:

[0096] Case 1: If the straight line section passes through the rupture fault zone, an S-shaped curve is needed to reconnect the local line to ensure the smoothness of train operation, as shown in (a) of Figure 4 , at this time, the length of the reconstructed line (Lr) is:

[0097] ; ; ;

[0098] ;

[0099] Wherein: is the length of the reconstructed circular curve (which needs to be greater than the minimum threshold lcmin); is the length of the reconstructed transition curve; is the radius of the reconstructed curve; is the minimum straight line length between adjacent circular curves; is the deflection angle; ​​​​​​This represents the displacement of the fault zone.

[0100] A suitable one can be found through simple iterative enumeration. and To determine .

[0101] Scenario 2: If the curve segment crosses a fracture zone, the local track can be reconstructed more directly in two ways, such as... Figure 4 As shown in (b). The first method keeps the straight lines unchanged and directly adjusts the radius of the deformed circular curve to reconnect them; the second method keeps the radius of the circular arc unchanged and reconstructs the common tangent connecting them.

[0102] In this embodiment, the inner Monte Carlo simulation cycle repeatedly performs random sampling to generate a statistical sample. The above steps are repeated until... k>K ( K (Define iteration limits for the user), resulting in two sets of data including direct loss and recovery time. K Data from a sample. For example... Figure 5 As shown in (a), two log-normal probability distribution curves are arranged in ascending order and fitted (taking direct loss as an example, denoted as...). Completed for a single level. p Model the probability distribution of the risk loss. Let p=p +1.

[0103] In this embodiment, the outer Monte Carlo simulation loop iterates through each level. p until p >3, thus obtaining the set of log-normal probability distribution curves for direct losses and recovery time under common, occasional, and rare earthquakes. For example... Figure 5 As shown in (b), the transcendence probability corresponding to the third-level PGD can be calculated. .

[0104] In this embodiment, based on the following formula, the theoretical annual exceedance probability of loss values ​​is calculated by integrating all PGD hazard levels, and the Monte Carlo simulation results are probabilistically fused with the seismic hazard analysis:

[0105] .

[0106] Further optimization, for engineering problems, only Level 3 PGD disasters (corresponding to common, occasional, and rare earthquakes) are considered, thus simplifying it to:

[0107] ;

[0108] in: The probability difference between two levels of hazards on the fault zone displacement probability hazard curve is detailed in [link to relevant documentation]. Figure 5 As shown in (c). Therefore, the exceedance probability curve of annual direct loss is as follows.Figure 5 (d) is shown in FIG. 4.

[0109] In this example, the final annual direct loss is estimated according to the following formula:

[0110]

[0111] where: G Figure 5 The number of segments of the abscissa in (d) is defined by the route designer. Similarly, the annual recovery time of the same structure is obtained.

[0112] In this example, the total route-fault zone intersection risk is summarized. Until >M M After determining the route reconstruction length caused by the fault zone displacement, the structure repair cost is estimated according to the given DS, damage ratio, and recovery days. Further, the total annual loss of all fault zone intersections along the route (L) is considered:

[0113]

[0114] where: N The number of route-fault zone intersections. This formula sums the direct loss of structure repair after rupture; but based on the assumption that rescue personnel and resources are sufficient after the earthquake, the indirect loss only takes the maximum repair time value in the route-fault zone intersection, i.e. the railway closure time only depends on the maximum repair time of all fault zone sections.

[0115] In this example, the cost-risk net present value is calculated to complete the evaluation of a single route scheme. That is, the direct basis for judging the pros and cons of the scheme, the smaller the cost-risk net present value, the better the railway route selection scheme. The cost-risk net present value (C) of the final fault zone full probability risk analysis model is the objective function:

[0116]

[0117]

[0118]

[0119] where: Construction cost; Railway construction period; Time period considered in the seismic risk assessment; Interest rate; Series of present value coefficients; ​​​​​​​​​for single payment present value factor; for time.

[0120] The above merely provides the preferred embodiments of the present application, but not for limiting the patent scope of the present application. Any equivalent structure variations made according to the present application's concept, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present application.

Claims

1. A method for full probability risk assessment of railway route selection schemes crossing seismic faults, characterized in that, Includes the following steps: Step S1: Obtain railway alignment schemes; obtain the number M of fault zones contained in each railway alignment scheme; determine the type of each fault zone, which includes primary fault zones and secondary fault zones. Step S2: Number each fault-track intersection in the railway alignment scheme. , =1,2,3,…,M; Step S3, for the first Perform fault zone displacement probability hazard analysis at each fault-line intersection point and generate its displacement hazard curve; Step S4: Establish and simulate a full probability risk analysis model for crossing fault zones using Monte Carlo simulation, suitable for railway alignment design. This includes: Step S4.1: Initialize the Monte Carlo iteration count. =1 and the series of PGD =1; Step S4.2: Determine the displacement input of the main fault zone, specifically: sample the third-level permanent ground displacement PGD exceeding the set probability from the disaster curve obtained in step S3; and then... The fault zone displacement value of the PGD level is input into the probabilistic vulnerability analysis model of railway structures to calculate the probability of the structure being in different damage states. The displacement input for determining secondary fault zones specifically involves: searching for existing line-fault zone intersections; calculating and obtaining the average displacements of all secondary fault zones near the main fault zone under three types of earthquakes: frequent, occasional, and rare; and then... The average displacement value of the fracture zone of the PGD level is input into the probabilistic vulnerability analysis model of railway structures to calculate the probability of the structure being in different damage states. Step S4.3: Combine the probability of the structure being in different damage states to obtain the probabilistic economic loss analysis after the railway is interrupted. The probabilistic economic loss analysis after the railway is interrupted includes: randomly obtaining the damage ratio and recovery time of the structure according to the probability distribution form, determining the reconstruction length of the line after the interruption and calculating the direct repair loss. Step S4.4, take = +1, perform a judgment, if If it is less than or equal to K, then return to step S4.2; if If the count is greater than K, proceed to the next step; K is the maximum count value for the set iteration. Step S4.3, take = +1, perform a judgment, if If it is greater than 3, proceed to the next step; if If the value is less than or equal to 3, return to step S4.2; Step S5: Calculate the theoretical annual exceedance probability of the loss value based on the economic loss analysis of the railway failure probability obtained in S4. Step S6: Estimate the final annual direct loss based on the theoretical exceedance probability of the loss value; Step S7, Take = +1, perform a judgment, if If it is greater than M, proceed to the next step; if If M is less than or equal to M, return to step S3; Step S8: Summarize the risks of all line-fault zone intersections to obtain the total annual loss of all fault zone intersections along the railway line; calculate the cost-risk net present value based on the total annual loss of all fault zone intersections along the railway line.

2. The method for full probability risk assessment of railway route selection schemes crossing seismic faults as described in claim 1, characterized in that, Both the main fault zone and the secondary fault zone contain normal faults, reverse faults, and strike-slip faults.

3. The full probability risk assessment method for railway route selection crossing seismic faults as described in claim 1, characterized in that, In step S4.2: Sample the Level 3 permanent ground displacement PGD with a 50-year exceedance probability of 63% / 10% / 2% from the hazard curve; A value of 1 represents a frequently encountered event. A value of 2 represents a chance encounter. A value of 3 represents a rare occurrence; different damage states include no damage, moderate damage, and severe damage.

4. The full probability risk assessment method for railway route selection crossing seismic faults as described in claim 3, characterized in that, The probabilistic vulnerability analysis model for railway structures includes the following steps: ① Divide railway lines into three structural groups: bridges, tunnels, and roadbed sections; ② Define the damage state of tunnels and roadbed sections crossing active fault zones; using PGD as the seismic intensity index, derive the following log-normal distribution for different structure types and damage states. Vulnerability curve: ； in: Indicates taking in PGD Damage state greater than The conditional probability; DS represents the damage state. For the index of DS, A value of 0 represents no damage. Let 1 represent moderate damage. A value of 2 represents severe damage; For the first The median of each DS; For the first Deviation of each DS; A specific value taken by PGD; ③ Calculate the probability of the structure being in different damage states.

5. The full probability risk assessment method for railway route selection crossing seismic faults as described in claim 4, characterized in that, The probabilities of the structure being in different damage states are calculated as follows: ； ； ； in: Represents the probability of a damage-free state; Represents the probability of a moderate damage state; This represents the probability of a state of severe injury.

6. The method for full probability risk assessment of railway route selection schemes crossing seismic faults as described in claim 1, characterized in that, The following formula is used to calculate the cost minus the net present value of risk to evaluate a single route option: ； ； ； in: For construction costs; The total annual loss at all intersections of fault zones along the railway line; For a series of present value coefficients; For interest rates; The time frame considered for earthquake risk assessment; For railway construction period; The present value factor for a single payment; For time.

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