A method for predicting gas leakage risk under the coupling action of multiple disasters

Abstract

The present invention discloses a method for predicting the risk of gas leakage under the coupling action of multiple disasters, comprising the following steps: S1, refining the factor granularity of the coupling events of multiple disasters such as rainstorm - land subsidence - gas pipeline network leakage, and determining the event factors and event factor spectrograms of rainstorm events, land subsidence events, gas pipeline fracture events, and gas pipeline network leakage events with a five - level structure; S2, calculating the coupling relationship of the precursory factors of multiple disasters; S3, constructing a risk degree function of the top event of the rainstorm - land subsidence - gas pipeline network leakage multiple - disaster coupling event chain according to the coupling relationship of the precursory factors of multiple disasters to achieve the prediction of the risk of gas leakage. The present invention can calculate the correlation of each disaster event in space and time, identify the behavior pattern of the disaster in space, so as to effectively measure the disaster. It can not only complete the estimation of the consequences of single - disaster events, but also match the coupling degree of multiple disasters, and further achieve the prediction of the risk of gas leakage.

Description

Technical Field

[0001] The present invention relates to the technical field of gas risk prediction, and in particular to a gas leakage risk prediction method under the coupling action of multiple disasters. Background Art

[0002] In the prevention and control of multi-disaster coupling accidents in urban gas pipe networks, geological disasters, typhoons, and heavy rains are the most typical initial events that trigger technical disasters. In 2010, Krausrnamit et al. evaluated the impact of the Wenchuan earthquake on industrial facilities, confirmed the damage mechanism and failure mode of underground pipelines caused by geological disasters, and proved the impact of the service life of facilities on disaster resistance; in 2012, Zareian et al. studied the damage caused by offshore earthquakes to industrial facilities and pipelines. At the same time, Chinese scholars started the research on the action of a single disaster on urban infrastructure earlier. In 2000, Yang Weiguo et al. established a probability equation for pipelines to reach different damage states in geological disasters by analyzing the damage degrees of different types of industrial installations at home and abroad under the influence of earthquakes and using the "probability theory" method; Cao Huaming et al. analyzed the impact of geological disasters on underground pipeline damage. Currently, the research methods for disaster chains at home and abroad mainly include the following categories: 1. Geological engineering method; this method focuses on the physical properties of rock and soil in the disaster-bearing environment, and through stability analysis and energy balance calculation, it is used to solve the occurrence, development, impact, prevention, and control of disaster chains, and is mostly used to solve large-scale disasters caused by earthquakes, landslides, dam breaches, etc.; 2. Comprehensive geographical assessment method; according to the theory of the earth's surface system, it is considered that the earth's surface is a unified natural environment, which determines the inevitable spatial correlation between different natural disasters; 3. System dynamics method; the system dynamics method learns and understands the dynamic behavior of the entire information feedback system through computational simulation. This method can quantify and process high-order nonlinear, multi-feedback, and complex time-varying systems, and can take into account both the disaster information flow and mechanism in the field of disasters. Therefore, it is one of the effective means for studying disaster chains. However, the system dynamics method is difficult to clarify the spatio-temporal and temporal correlations of each subsystem, and cannot identify the behavior patterns of disasters in space, resulting in the inability to effectively measure disasters. Summary of the Invention

[0003] The purpose of the present invention is to provide a gas leakage risk prediction method under the coupling action of multiple disasters to solve the deficiencies in the prior art, refine the factor granularity of the multi-disaster coupling event of heavy rain - ground settlement - gas pipe network leakage, calculate the coupling relationship of multi-disaster precursor factors, and thus realize the prediction of gas leakage risk.

[0004] The present invention is realized through the following technical solutions: A gas leakage risk prediction method under the coupling action of multiple disasters, comprising the following steps:

[0005] S1. Obtain rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events, and decompose the above five types of events by granularity to determine the event factors and event factor spectrograms of rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events with a five-level structure;

[0006] S2. According to the event factors of each event described in step S1, determine the coupled precursor factors, coupling forces as well as the temporal and spatial correlations of rainstorm events and ground settlement events, and determine the coupled precursor factors, coupling forces as well as the temporal and spatial correlations of ground settlement events and gas pipeline network leakage events, and determine the coupled precursor factors, coupling forces as well as the temporal and spatial correlations of gas pipeline fracture events and gas pipeline network leakage events;

[0007] S3. Based on and construct an event risk degree function for the multi-disaster coupling event chain of rainstorm-ground settlement-gas pipeline network leakage, and finally predict the gas leakage risk under the coupling action of rainstorm events, ground settlement events, and gas pipeline fracture events.

[0008] Furthermore, in step S1, the following operations are specifically performed:

[0009] Decompose the rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events by granularity, determine the disaster-causing factors and disaster-bearing carriers of rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events, and construct the five-level structure event factors and event factor spectrograms of the disaster-causing factors and disaster-bearing carriers of each event.

[0010] Furthermore, in step S2, the determination of the coupled precursor factors, coupling forces with time and spatial correlations includes the following steps:

[0011] S201. Refine the granularity of rainstorm event and ground settlement event factors, and construct a factor library for rainstorm events and ground settlement events as:

[0012] {Precipitation, groundwater level line, foundation pit dewatering height};

[0013] S202. Compile a PS program, and calculate the change in the groundwater level caused by rainstorm impacts according to the rainstorm-internal flooding dynamics model. The calculation formula is:

[0014] where, Δh represents the change in the groundwater level line, with the unit of m; Q rDenote the rainfall as \(m^3\); \(S\) represents the infiltration area with the unit of \(m^2\); \(n\) represents the number of infiltration paths; \(q\) i represents the rainfall intensity with the unit of \(m^3 / min\); \(\psi\) represents the infiltration coefficient; \(t\) represents the rainfall time with the unit of \(min\);

[0015] And obtain the pore water flow models in all directions according to the soil infiltration capacity, and its calculation formula is:

[0016]

[0017] Among them, \(x\), \(y\), \(z\) represent the spatial orientation; \(u\) represents the change rate of the water volume flowing through the surface of the soil element; \(k\) x , \(k\) y , \(k\) z respectively represent the infiltration coefficients of the homogeneous soil in the \(x\), \(y\), \(z\) directions; \(\gamma\) w represents the unit weight of pore water; \(q\) x , \(q\) y , \(q\) z respectively represent the unit flow rates in the \(x\), \(y\), \(z\) directions;

[0018] At the same time, analyze the seepage equilibrium equation of soil pore water to obtain the relationship between displacement and pore water stress, and its calculation formula is:

[0019]

[0020]

[0021]

[0022] Among them, \(G\) represents the shear modulus of the soil; \(w\) x , \(w\) y , \(w\) z respectively represent the soil displacements in the \(x\), \(y\), \(z\) directions, \(u\) represents the change rate of the water volume flowing through the surface of the soil element; \(\gamma\) w represents the unit weight of pore water;

[0023] S203. According to each formula calculated in step S202, perform semantic search on the factor library described in step S201. When the coupling degree between the disaster event factors in the factor library and each formula calculated in step S202 is greater than or equal to 2, determine that the disaster event factor is a near-miss factor, and the set of coupling near-miss factors for the rainstorm event and the land subsidence event is:

[0024] {water level difference, pore water head};

[0025] S204. According to the constructed set of coupling near-miss factors {water level difference, pore water head} for the rainstorm event and the land subsidence event, obtain the coupling force between the rainstorm event and the land subsidence event Represents the three-dimensional matrix of soil displacement formed at time t, through the coupling force of rainstorm events and land subsidence events Construct the time and space correlation of precursor factors for rainstorm events and land subsidence events, where w x , w y , w z respectively represent the soil displacements in the x, y, and z directions.

[0026] Furthermore, in step S2, the determination of the coupling precursor factors, coupling forces between the land subsidence event and the gas pipeline leakage event, and the time and space correlation, includes the following steps:

[0027] S211. Refine the factor granularity of the land subsidence event and the gas pipeline leakage event, and construct the factor library of the land subsidence event and the gas pipeline leakage event as:

[0028] {Pipeline failure rate, soil internal stress};

[0029] S212. Compile the SS program, and according to the soil consolidation settlement dynamics model, calculate the relationship between the effective stress and the soil strain, and then obtain the changes in the geological environment caused by the influence of rainstorms. The calculation formula is:

[0030]

[0031]

[0032] where ε v represents the soil volume strain; ε x , ε y , ε z represent the strains of the soil volume in the x, y, and z directions; σ′ x , σ′ y , σ′ z represent the effective stresses of the soil in the x, y, and z directions; τ x , τ y , τ z represent the unit seepage forces in the x, y, and z directions; ε xy represents the strain of the soil volume in the x and y directions; ε yz represents the strain of the soil volume in the y and z directions; ε zx represents the strain of the soil volume in the x and z directions; u represents the change rate of the water volume flowing through the surface of the soil element body;

[0033] At the same time, calculate the attenuation of stress waves in the soil. The calculation formula is:

[0034] σ′ i =σ′i / D ε ,

[0035] ε = (2 + σ 土壤 ) / (1 - σ 土壤 );

[0036] where σ′ i is the effective stress of the soil in the i direction, i ∈ {x, y, z}; D is the stress wave attenuation coefficient of the soil; ε is the Darcy number; σ 土壤 is the stress diffusion coefficient of the soil;

[0037] S213. According to each formula calculated in step S212, perform semantic search on the factor library described in step S211. When the coupling degree between the disaster event factors in the factor library and each formula calculated in step S212 is greater than or equal to 2, determine it as a precursor factor, and obtain the set of coupling precursor factors for the ground settlement event and the gas pipeline leakage event as:

[0038] {soil internal stress, external force factor};

[0039] S214. According to the set of coupling precursor factors {soil internal stress, external force factor} for the ground settlement event and the gas pipeline leakage event, obtain the coupling force representing the three-dimensional matrix of soil stress formed at time t; through the coupling force of the ground settlement event and the gas pipeline leakage event, construct the time and space correlation of the precursor factors for the ground settlement event and the gas pipeline leakage event; where σ′ x , σ′ y , σ′ z represent the effective stresses of the soil in the x, y, and z directions.

[0040] Furthermore, in step S2, the determination of the coupling precursor factors, coupling force and time and space correlation of the gas pipeline fracture event and the gas pipeline leakage event includes the following steps:

[0041] S221. Refine the factor granularity of the gas pipeline fracture event and the gas pipeline leakage event, and construct the factor library of the gas pipeline fracture event and the gas pipeline leakage event as:

[0042] {bush, green belt, low eaves, warehouse, temperature, lightning strike, open fire source};

[0043] S222. According to the Smith-Watson-Topper criterion, perform fatigue brittle fracture judgment on the gas pipeline, calculate the crack size at the pipeline failure point and the leakage velocity q(t), where q(t) is the gas leakage flow velocity at time t;

[0044] S223. Establish a gas diffusion model under the comprehensive influence of buildings such as vegetation, low-rise buildings, and warehouses.

[0045]

[0046] The fracture stress of the gas pipeline structure caused by the influence of heavy rain, obtain q(t) according to the gas pipeline failure dynamics model, and calculate the spatial gas concentration distribution C(x, y, z, t) according to various diffusion coefficients σ x ,σ g ,σ w ,σ c ,where σ x is the atmospheric diffusion coefficient, σ g is the agglomeration effect of vegetation factors such as {shrubbery, green belt, trees} on the diffused gas, σ w is the agglomeration effect of low-rise building structures such as {low eaves, warehouses} on the gas, σ c is the agglomeration effect of buildings such as warehouses on the gas, C(x, y, z, t) represents the leakage gas concentration at (x, y, z) at time t, is the environmental wind speed;

[0047] S224. Compile a GB program to calculate the spatial distribution of the leaked gas in a complex environment with multi-hazard coupling.

[0048] S225. According to the constructed coupling precursor factor set {pipeline leakage rate, gas concentration} of the gas pipeline fracture event and the gas pipeline network leakage event, obtain the coupling force of {pipeline leakage rate, gas concentration} represents the pipeline leakage degree formed at time t; through the coupling force of the gas pipeline fracture event and the gas pipeline network leakage event, construct the temporal and spatial correlation of the precursor factors of the gas pipeline fracture event and the gas pipeline network leakage event; where, C(x, y, z, t) represents the leakage gas concentration at (x, y, z) at time t.

[0049] Furthermore, in step S3, it includes the following steps:

[0050] S301. Based on the coupling force and create a multi-hazard coupling event chain of rainfall-geological disaster-gas pipeline network leakage;

[0051] S302. According to the material properties, determine the risk probability of the gas pipeline network leakage event under the coupling action of rainfall-geological disaster:

[0052]

[0053] Among them, P(T1T2T3T4) represents the risk of a multi-hazard coupling event of rainfall - geological disaster - gas pipeline network leakage; T i represents the i-th event, where i ∈ {1, 2, 3, 4}; T1 represents a rainstorm event, T2 represents a ground settlement event, T3 represents a gas pipeline fracture event, and T4 represents a gas leakage event; pa represents the coupling force and the set of; represents the coupling force or the conditional probability of rainfall, geological disasters, gas pipeline network fractures, and gas leakage events when it is greater than the structural strength.

[0054] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0055] The present invention can calculate the correlation of each disaster event in space and time, identify the behavior pattern of disasters in space, so as to effectively measure disasters. It can not only complete the estimation of the consequences of single-hazard disasters, but also match the coupling degree of multi-hazards, and further realize the prediction of gas leakage risk under the coupling action of rainstorm events, ground settlement events, and gas pipeline network leakage events. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a flowchart of the present invention.

[0057] Figure 2 is a schematic diagram of the event factor set of a rainstorm event.

[0058] Figure 3 is a schematic diagram of the event factor set of a ground settlement event.

[0059] Figure 4 is a schematic diagram of the event factor set of a gas pipeline network leakage event.

[0060] Figure 5 is a relationship diagram of the precursor factors of a rainstorm event and a ground settlement event.

[0061] Figure 6 is a relationship diagram of the precursor factors of a ground settlement event and a gas pipeline network leakage event.

[0062] Figure 7 is a relationship diagram of the precursor factors of a gas pipeline network leakage event and a gas explosion. DETAILED DESCRIPTION OF THE INVENTION

[0063] The present invention will be further described below with reference to specific embodiments.

[0064] See Figures 1 to 7As shown in the figure, the gas leakage risk prediction method under the coupling action of multiple disasters provided by this embodiment includes the following steps:

[0065] S1. Obtain rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events, and decompose the above five types of events into granularity to determine the event factors and event factor spectrograms of rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events with a five-level structure. Specifically, perform the following operations:

[0066] Decompose rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events into granularity, determine the disaster-causing factors and disaster-bearing carriers of rainstorm events, ground settlement events, gas pipeline fracture events, and gas pipeline network leakage events, and construct event factors and event factor spectrograms with a five-level structure for the disaster-causing factors and disaster-bearing carriers of each event.

[0067] S2. According to the event factors of each event described in step S1, determine the coupling hazard factors, coupling acting forces as well as the time and space correlations between rainstorm events and ground settlement events, determine the coupling hazard factors, coupling acting forces as well as the time and space correlations between ground settlement events and gas pipeline network leakage events, and determine the coupling hazard factors, coupling acting forces as well as the time and space correlations between gas pipeline fracture events and gas pipeline network leakage events;

[0068] The determination of the coupling hazard factors, coupling acting forces between rainstorm events and ground settlement events and the time and space correlations includes the following steps:

[0069] S201. Refine the granularity of rainstorm event and ground settlement event factors, and construct a factor library for rainstorm events and ground settlement events as follows:

[0070] {Precipitation, groundwater level line, foundation pit dewatering height};

[0071] S202. Compile a PS program, and calculate the change in the groundwater level caused by the influence of rainstorms according to the rainstorm-internal flooding dynamics model. The calculation formula is:

[0072] where Δh represents the change in the groundwater level line, with the unit of m; Q r represents the rainfall, with the unit of m 3 ; S represents the infiltration area, with the unit of m 2 ; n represents the number of infiltration paths; q i represents the rainfall intensity, with the unit of m 3 / min; ψ represents the infiltration coefficient; t represents the rainfall time, with the unit of min;

[0073] And obtain the pore water flow models in all directions according to the soil permeability, and its calculation formula is:

[0074]

[0075] Wherein, x, y, z represent the spatial orientation; u represents the rate of change of the amount of water flowing through the surface of the soil element; k x , k y , k z respectively represent the permeability coefficients of the homogeneous soil in the x, y, and z directions; γ w represents the unit weight of the pore water; q x , q y , q z respectively represent the unit flow rates in the x, y, and z directions;

[0076] At the same time, analyze the soil pore water seepage equilibrium equation to obtain the relationship between displacement and pore water stress, and its calculation formula is:

[0077]

[0078]

[0079]

[0080] Wherein, G represents the shear modulus of the soil; w x , w y , w z respectively represent the soil displacements in the x, y, and z directions, u represents the rate of change of the amount of water flowing through the surface of the soil element; γ w represents the unit weight of the pore water;

[0081] S203. According to each formula calculated in step S202, perform semantic search on the factor library described in step S201. When the coupling degree between the disaster event factors in the factor library and each formula calculated in step S202 is greater than or equal to 2, determine that the disaster event factor is a precursor factor, and the set of coupling precursor factors for the rainstorm event and the land subsidence event is:

[0082] {water level difference, pore water head};

[0083] S204. According to the constructed set of coupling precursor factors {water level difference, pore water head} for the rainstorm event and the land subsidence event, obtain the coupling force between the rainstorm event and the land subsidence event represents the three-dimensional matrix of soil displacement formed at time t, and through the coupling force between the rainstorm event and the land subsidence event Construct the time and space correlation of the precursor factors for the rainstorm event and the land subsidence event, where w x , w y , w z respectively represent the soil displacements in the x, y, and z directions.

[0084] The determination of the coupling omen factors, coupling acting forces between the ground settlement event and the gas pipeline network leakage event, and their time and space correlations, include the following steps:

[0085] S211. Refine the factor granularity of the ground settlement event and the gas pipeline network leakage event, and construct the factor library of the ground settlement event and the gas pipeline network leakage event as:

[0086] {pipe failure rate, soil internal stress};

[0087] S212. Compile the SS program, and according to the soil consolidation settlement dynamics model, calculate the relationship between the effective stress and the soil strain, and then obtain the changes in the geological environment caused by the influence of heavy rain. Its calculation formula is:

[0088]

[0089]

[0090] where ε v represents the soil volume strain; ε x , ε y , ε z represent the strains of the soil volume in the x, y, and z directions; σ′ x , σ′ y , σ′ z represent the effective stresses of the soil in the x, y, and z directions; τ x , τ y , τ z represent the unit seepage forces in the x, y, and z directions; ε xy represents the strain of the soil volume in the x and y directions; ε yz represents the strain of the soil volume in the y and z directions; ε zx represents the strain of the soil volume in the x and z directions; u represents the change rate of the water volume flowing through the surface of the soil element;

[0091] At the same time, calculate the attenuation of the stress wave in the soil. Its calculation formula is:

[0092] σ′ i = σ′ i / D ε ,

[0093] ε = (2 + σ 土壤 ) / (1 - σ 土壤 );

[0094] Among them, σ′ i is the effective stress of the soil in the i direction, where i ∈ {x, y, z}; D is the attenuation coefficient of the soil stress wave; ε is the Darcy number; σ 土壤 is the soil stress diffusion coefficient;

[0095] S213. According to each formula calculated in step S212, perform semantic search on the factor library described in step S211. When the coupling degree between the disaster event factors in the factor library and each formula calculated in step S212 is greater than or equal to 2, determine it as a precursor factor. The set of coupling precursor factors for the ground settlement event and the gas pipeline network leakage event is:

[0096] {Soil internal stress, external force factor};

[0097] S214. According to the set of coupling precursor factors {Soil internal stress, external force factor} for the ground settlement event and the gas pipeline network leakage event, obtain the coupling acting force between the ground settlement event and the gas pipeline network leakage event represents the three-dimensional matrix of soil stress formed at time t; through the coupling acting force between the ground settlement event and the gas pipeline network leakage event construct the time and space correlation of the precursor factors for the ground settlement event and the gas pipeline network leakage event; among them, σ′ x , σ′ y , σ′ z represent the effective stresses of the soil in the x, y, and z directions.

[0098] The determination of the coupling precursor factors, coupling acting force and time and space correlation between the gas pipeline fracture event and the gas pipeline network leakage event includes the following steps:

[0099] S221. Refine the factor granularity of the gas pipeline fracture event and the gas pipeline network leakage event, and construct the factor library of the gas pipeline fracture event and the gas pipeline network leakage event as:

[0100] {Bush, green belt, low eaves, warehouse, temperature, lightning strike, open fire source};

[0101] S222. According to the Smith-Watson-Topper criterion, perform fatigue brittle fracture judgment on the gas pipeline, calculate the crack size at the pipeline failure point and the leakage velocity q(t), where q(t) is the gas leakage flow velocity at time t;

[0102] S223. Establish a gas diffusion model under the comprehensive influence of vegetation, low-rise buildings, and warehouses, etc.

[0103]

[0104] The fracture stress of the gas pipeline structure caused by heavy rain is obtained as q(t) according to the gas pipeline failure dynamics model, and the spatial gas concentration distribution C(x, y, z, t) is deduced based on various diffusion coefficients σ x , σ g , σ w , σ c , σ x is the atmospheric diffusion coefficient, σ g is the agglomeration effect of vegetation factors such as {bushes, green belts, trees} on the diffused gas, σ w is the agglomeration effect of low-rise building structures such as {low eaves, warehouses} on the gas, σ c is the agglomeration effect of buildings such as warehouses on the gas, and C(x, y, z, t) represents the leakage gas concentration at (x, y, z) at time t, is the environmental wind speed;

[0105] S224. Compile the GB program to calculate the spatial distribution of the leaked gas in the complex environment with multiple disasters coupled;

[0106] S225. According to the coupling precursor factor set {pipeline leakage rate, gas concentration} of the gas pipeline fracture event and the gas pipeline network leakage event, obtain the coupling acting force of {pipeline leakage rate, gas concentration} represents the pipeline leakage degree formed at time t; through the coupling acting force of the gas pipeline fracture event and the gas pipeline network leakage event, construct the time and space correlation of the precursor factors of the gas pipeline fracture event and the gas pipeline network leakage event; where, C(x, y, z, t) represents the leakage gas concentration at (x, y, z) at time t.

[0107] S3. Based on and construct the event risk degree function of the multi-disaster coupling event chain of heavy rain - ground settlement - gas pipeline network leakage, and finally predict the gas leakage risk under the coupling action of the heavy rain event, the ground settlement event and the gas pipeline fracture event, including the following steps:

[0108] S301. Create a multi-disaster coupling event chain of rainfall - geological disaster - gas pipeline network leakage based on the coupling acting force and ;

[0109] S302. Determine the risk probability of the gas pipeline network leakage event under the coupling action of rainfall - geological disaster according to the material properties:

[0110]

[0111] Among them, P(T1T2T3T4) represents the risk of the multi-hazard coupling event of rainfall-geohazard-gas pipeline leakage; T i represents the i-th event, where i ∈ {1, 2, 3, 4}; T1 represents the heavy rain event, T2 represents the ground settlement event, T3 represents the gas pipeline fracture event, and T4 represents the gas leakage event; pa represents the coupling force and the set of; represents the coupling force or the conditional probability of rainfall, geohazard, gas pipeline fracture, and gas leakage events when it is greater than the structural strength.

[0112] The above-described embodiments are only the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and shall be covered by the protection scope of the present invention.

Claims

1. A method for predicting the risk of gas leakage under the coupling action of multiple disasters, characterized in that, It includes the following steps: S1. Obtain rainstorm events, land subsidence events, gas pipeline fracture events, and gas pipeline network leakage events, and decompose the granularity of the above four types of events to determine the event factors and event factor spectrograms of rainstorm events, land subsidence events, gas pipeline fracture events, and gas pipeline network leakage events with a five-level structure; S2. Determine the coupled precursor factors and coupling forces of rainstorm events and land subsidence events based on the event factors of each event described in step S1 And the time and space correlations, determine the coupled precursor factors and coupling forces of land subsidence events and gas pipeline network leakage events And the time and space correlations, and determine the coupled precursor factors and coupling forces of gas pipeline fracture events and gas pipeline network leakage events And the time and space correlations; S3. Based on and Construct an event risk degree function for the multi-disaster coupling event chain of rainstorm - land subsidence - gas pipeline leakage, and finally predict the gas leakage risk under the coupling effect of rainstorm events, land subsidence events and gas pipeline fracture events, including the following steps: S301. Based on the coupling force and Create a multi-disaster coupling event chain of rainfall-ground subsidence-gas pipeline leakage S302. Determine the risk probability of gas pipeline network leakage events under the coupling action of rainfall and land subsidence according to material properties: Among them, P(T1T2T3T4) represents the risk of multi-hazard coupling events of rainfall - land subsidence - gas pipeline network leakage; T i represents the i-th event, where i ∈ {1, 2, 3, 4}; T1 represents the rainstorm event, T2 represents the land subsidence event, T3 represents the gas pipeline fracture event, and T4 represents the gas leakage event; pa represents the coupling force and the set of; represents the coupling force or the conditional probability of rainfall, land subsidence, gas pipeline network fracture, and gas leakage events when it is greater than the structural strength.

2. A method for predicting the risk of gas leakage under the coupling action of multiple disasters according to claim 1, wherein In step S1, the following operations are specifically performed: Decompose the granularity of rainstorm events, land subsidence events, gas pipeline fracture events, and gas pipeline network leakage events to determine the disaster-causing factors and disaster-bearing carriers of rainstorm events, land subsidence events, gas pipeline fracture events, and gas pipeline network leakage events, and construct the five-level structure event factors and event factor spectrograms of the disaster-causing factors and disaster-bearing carriers of each event.

3. A method for predicting the risk of gas leakage under the coupling action of multiple disasters according to claim 1, characterized in that, In step S2, determining the coupled omen factors, coupled acting forces of the rainstorm event and the land subsidence event, and the time and space correlations, includes the following steps: S201. Refine the granularity of rainstorm event and land subsidence event factors, and construct the factor library of rainstorm events and land subsidence events as: {Precipitation, groundwater level line, foundation pit dewatering height}; S202. Compile a PS program to calculate the change in the groundwater level caused by rainstorms according to the rainstorm-internal flooding dynamics model. The calculation formula is as follows: Among them, Δh represents the change in the groundwater level line, with the unit of m; Q r represents the rainfall, with the unit of m 3 ; S represents the infiltration area, with the unit of m 2 ; n represents the number of infiltration paths; q i represents the rainfall intensity, with the unit of m 3 / min; ψ represents the permeability coefficient; t represents the rainfall time, with the unit of min; And obtain the pore water flow model in each direction according to the soil permeability, and its calculation formula is: where x, y, z represent the spatial orientation; u represents the rate of change of the amount of water flowing through the surface of the soil element; k x , k y , k z respectively represent the permeability coefficients of the homogeneous soil in the x, y, and z directions; γ w represents the unit weight of pore water; q x , q y , q z respectively represent the unit flow rates in the x, y, and z directions; At the same time, analyze the soil pore water seepage equilibrium equation to obtain the relationship between displacement and pore water stress, and its calculation formula is: Among them, G represents the shear modulus of the soil mass; w x , w y , w z respectively represent the soil displacements in the x, y, and z directions, and u represents the rate of change of the amount of water flowing through the surface of the soil element; γ w represents the unit weight of pore water; S203. According to the various formulas calculated in step S202, conduct semantic search on the factor library described in step S201. When the coupling degree between the disaster event factors in the factor library and the various formulas calculated in step S202 is greater than or equal to 2, determine that the disaster event factor is a precursor factor, and obtain the set of coupling precursor factors of rainstorm events and land subsidence events as: {Water level difference, pore water head}; S204. Obtain the coupling force between the rainstorm event and the land subsidence event according to the set of coupling precursor factors {water level difference, pore water head} for the rainstorm event and the land subsidence event represents the three-dimensional matrix of soil displacement formed at time t, through the coupling force between the rainstorm event and the land subsidence event Construct the temporal and spatial correlations of the precursor factors for the rainstorm event and the land subsidence event, where w x , w y , w z represent the soil displacements in the x, y, and z directions respectively.

4. A method for predicting the risk of gas leakage under the coupling action of multiple disasters according to claim 1, characterized in that, In step S2, determining the coupled precursor factors, coupled acting forces of the land subsidence event and the gas pipeline network leakage event, and the time and space correlations, includes the following steps: S211. Refine the granularity of land subsidence event and gas pipeline network leakage event factors, and construct the factor library of land subsidence events and gas pipeline network leakage events as: {Pipeline failure rate, soil internal stress}; S212. Compile the SS program, calculate the relationship between effective stress and soil strain according to the soil consolidation settlement dynamics model, and then obtain the changes in the geological environment caused by rainstorm impacts, and its calculation formula is: Among them, ε v represents the volumetric strain of the soil mass; ε x , ε y , ε z represent the strains of the soil mass in the x, y, and z directions of the volume; σ′ x , σ′ y , σ′ z represent the effective stresses of the soil mass in the x, y, and z directions; τ x , τ y , τ z represent the unit seepage forces in the x, y, and z directions; ε xy represents the strain of the soil mass volume in the x and y directions; ε yz represents the strain of the soil mass volume in the y and z directions; ε zx represents the strain of the soil mass volume in the x and z directions; u represents the change rate of the water volume flowing through the surface of the soil element; G represents the shear modulus of the soil mass; w x , w y , w z respectively represent the soil displacements in the x, y, and z directions; At the same time, calculate the attenuation of stress waves in the soil, and its calculation formula is: σ i " = σ′ i / D ε , ε=(2 + σ 土壤 ) / (1 - σ 土壤 ); Among them, σ′ i is the effective stress of the soil mass in the i direction, where i ∈ {x, y, z}; D is the stress wave attenuation coefficient of the soil mass; ε is the Darcy number; σ 土壤 is the stress diffusion coefficient of the soil mass; S213. According to the various formulas calculated in step S212, conduct semantic search on the factor library described in step S211. When the coupling degree between the disaster event factors in the factor library and the various formulas calculated in step S212 is greater than or equal to 2, determine it as a precursor factor, and obtain the set of coupling precursor factors of land subsidence events and gas pipeline network leakage events as: {Soil internal stress, external force factor}; S214. Obtain the coupling acting force between the land subsidence event and the gas pipeline network leakage event according to the set of coupling precursor factors {soil internal stress, external force factor} of the land subsidence event and the gas pipeline network leakage event denote the three-dimensional matrix of soil stress formed at time t; through the coupling acting force between the land subsidence event and the gas pipeline network leakage event Construct the temporal and spatial correlations of the precursor factors of the land subsidence event and the gas pipeline network leakage event; where σ″ x , σ″ y , σ″ z denote the effective stress after attenuation in the x, y, and z directions of the soil mass.

5. A method for predicting gas leakage risk under the coupling action of multiple disasters according to claim 1, characterized in that, In step S2, determining the coupled precursor factors, coupled acting forces of the gas pipeline rupture event and the gas pipeline network leakage event, and the time and space correlations, includes the following steps: S221. Refine the granularity of gas pipeline fracture event and gas pipeline network leakage event factors, and construct the factor library of gas pipeline fracture events and gas pipeline network leakage events as: {Shrubbery, green belt, low eaves, warehouse, temperature, lightning strike, open fire source}; S222. Judge the fatigue brittle fracture of gas pipelines according to the Smith-Watson-Topper criterion, calculate the crack size at the pipeline failure point and the leakage velocity q(t), where q(t) is the gas leakage velocity at time t; S223. Establish a gas diffusion model under the comprehensive influence of vegetation, low-rise buildings, and warehouse buildings. The stress of the gas pipeline structure caused by the influence of heavy rain, q(t) is obtained according to the gas pipeline failure dynamics model, and the spatial gas concentration distribution C(x, y, z, t) is deduced according to various diffusion coefficients σ x , σ g , σ w , σ c , where σ x is the atmospheric diffusion coefficient, σ g is the agglomeration effect of vegetation factors such as {bushes, green belts, trees} on the diffused gas, σ w is the agglomeration effect of low-rise building structures such as {low eaves, warehouses} on the gas, σ c is the agglomeration effect of the warehouse building on the gas, C(x, y, z, t) represents the leakage gas concentration at (x, y, z) at time t, is the environmental wind speed; S224. Compile a GB program to calculate the spatial distribution of leaked gas in a complex environment with multi-hazard coupling. S225. According to the coupling precursor factor set {pipe leakage rate, gas concentration} for constructing the gas pipeline fracture event and the gas pipeline network leakage event, the coupling force of {pipe leakage rate, gas concentration} is obtained. represents the pipe leakage degree formed at time t; through the coupling force of the gas pipeline fracture event and the gas pipeline network leakage event Construct the temporal and spatial correlations of the precursor factors for the gas pipeline fracture event and the gas pipeline network leakage event; where C(x, y, z, t) represents the leaked gas concentration at (x, y, z) at time t.

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