Risk analysis method for storage yard emergency rescue system based on petri net

Abstract

The invention provides a risk analysis method for a storage yard emergency rescue system based on a petri net, and belongs to the field of storage yard emergency rescue. The method solves the problem of low credibility of storage yard risk analysis. The method is specifically as follows: step S1: constructing a first petri net model, a second petri net model, a third petri net model and a fourth petri net model for analyzing storage yard fire, leakage of dangerous goods, traffic accidents and container collapse respectively; step S2: performing a simulation analysis on the first petri net model, the second petri net model, the third petri net model and the fourth petri net model to obtain a storage yard risk primary analysis report; step S3: obtaining historical operation records of the storage yard, and counting and calculating the disaster weight of the storage yard; performing a secondary analysis on the storage yard risk primary analysis report in combination with the disaster weight to obtain a storage yard risk analysis report; the invention simulates and analyzes possible accidents in the storage yard, obtains the occurrence rate of each accident in the normal operation of the storage yard, and performs risk analysis for the storage yard operation and construction work.

Description

Technical Field

[0001] The invention discloses a risk analysis method for a storage yard emergency rescue system based on a petri net and relates to the field of storage yard emergency rescue. Background Art

[0002] Petri nets are a formal modeling tool proposed by German mathematician Carl Henrik Petri in 1962 to describe concurrent behaviors in concurrent systems. Petri nets consist of a set of places, transitions, arcs, and tokens; the basic principle of Petri nets is that places meet certain prerequisites, trigger transitions, and change the state of the system; through the modeling and analysis of Petri nets, concurrent systems or states can be vividly described, state transitions under certain behaviors or events, and help analyze the properties and performance of the system.

[0003] The existing systems or methods for applying petri nets to yard operations have the following deficiencies:

[0004] 1. Complex modeling: For complex systems, the modeling process of Petri nets is relatively complicated and requires a lot of time and effort. When modeling large systems, the state space will grow, making it more difficult to simulate and build.

[0005] 2. State explosion problem: During the modeling process, as the scale of the system increases, the state space of the Petri net will also grow exponentially, leading to the state explosion problem and increasing the difficulty of analysis.

[0006] 3. Difficulty in handling concurrent events: Petri nets have certain limitations when handling concurrent events. Sometimes it is difficult to accurately describe the concurrent behaviors in the system, resulting in inaccurate analysis results. At the same time, the selection and adjustment of parameters in the Petri net model may affect the final analysis results. It is more difficult to debug parameters, which has a greater impact on the accuracy of the prediction results. Summary of the invention

[0007] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a risk analysis method for a storage yard emergency rescue system based on a petri net, aiming to solve the problem of inaccurate estimation of the occurrence rate of various accidents in the normal operation of the storage yard and the problem of inaccurate accident costs.

[0008] In order to achieve the above object, the present invention is implemented through the following technical solutions: A risk analysis method for a storage yard emergency rescue system based on a petri net comprises:

[0009] Step S1: constructing a No. 1 petri net model for yard fire analysis, a No. 2 petri net model for yard dangerous goods leakage analysis, a No. 3 petri net model for yard traffic accident analysis, and a No. 4 petri net model for yard container collapse analysis;

[0010] Step S2: Perform a simulation analysis on the No. 1 Petri net model, the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model to obtain a primary analysis report on the storage yard risk;

[0011] Step S3: Obtain the historical operation records of the storage yard, count and calculate the disaster weight of the storage yard; conduct a secondary analysis on the primary risk analysis report of the storage yard in combination with the disaster weight to obtain a risk analysis report of the storage yard.

[0012] Furthermore, the specific steps of step S1 are as follows:

[0013] Step S11: constructing a No. 1 petri net model for yard fire analysis;

[0014] Step S12: constructing a No. 2 petri net model for analyzing leakage of dangerous goods in a storage yard;

[0015] Step S13: constructing a No. 3 petri net model for yard traffic accident analysis;

[0016] Step S14: constructing a No. 4 petri net model for container collapse analysis in a yard;

[0017] Furthermore, the subsequent steps of step S11 are as follows:

[0018] Step S111: define the library:

[0019] P11: Container status is normal;

[0020] P12: Fire hazard exists;

[0021] P13: Fire monitoring started;

[0022] P14: Fire breaks out;

[0023] P15: Fire spread;

[0024] P16: Fire response initiated;

[0025] P17: Fire extinguished;

[0026] Step S112: Define transitions:

[0027] T11: Fire hazard development;

[0028] T12: Start fire monitoring;

[0029] T13: Fire detected;

[0030] T14: Fire spread;

[0031] T15: Initiate fire response;

[0032] T16: Fire extinguished;

[0033] T17: Return to normal state;

[0034] T18: No fire hazard;

[0035] Step S113: Define directed edges:

[0036] P11->T11: When the container is in normal condition, a fire hazard may occur; T11->P12: A fire hazard exists;

[0037] P12->T12: After detecting a fire hazard, fire monitoring is started;

[0038] T12->P13: Fire monitoring in progress;

[0039] P13->T13: After the fire monitoring is completed, confirm whether a fire has occurred; T13->P14: Fire occurs;

[0040] P14->T14: Fire spreads to other containers or areas;

[0041] T14->P15: Fire spreading;

[0042] P15->T15: After the fire spreads, fire response is initiated;

[0043] T15->P16: Fire response in progress;

[0044] P16->T16: The fire brigade puts out the fire;

[0045] T16->P17: The fire was put out;

[0046] P17->T17: Clean up the scene and return to normal;

[0047] T17->P11: The container area returns to normal;

[0048] P11->T18: When the container is in normal condition, there is no fire hazard;

[0049] T18->P11: Container area is in normal state;

[0050] Step S114: define token:

[0051] Initial token: P11 has a token, indicating that the initial state of the container area is normal. After the transition occurs, the token of the corresponding place will change.

[0052] Furthermore, the specific steps of step S12 are as follows:

[0053] Step S121: define the library:

[0054] P21: The container is sealed intact;

[0055] P22: Container damaged;

[0056] P23: Leakage of dangerous goods;

[0057] P24: Leakage of non-dangerous goods;

[0058] P25: Evacuation of yard personnel;

[0059] P26: Cargo spill cleanup completed;

[0060] Step S122: define transition:

[0061] T21: Container cargo is damaged;

[0062] T22: Container cargo is intact;

[0063] T23: Cargo leakage inspection;

[0064] T24: Initiate emergency response;

[0065] T25: A dedicated person cleans up the leaked goods;

[0066] T26: Yard staff cleaned up the leaked cargo;

[0067] Step S123: Define directed edges:

[0068] P21->T21: When the container is sealed intact, cargo damage may occur;

[0069] T21->P22: Container damaged;

[0070] P22->T23: Check the damaged container for leaked cargo;

[0071] T23->P23: Dangerous goods leakage;

[0072] P23->T24: Initiate emergency response measures;

[0073] T24->P25: Dangerous goods leak, evacuate yard personnel;

[0074] P25->T25: The yard manager invites professionals to clean up the leak of dangerous goods;

[0075] T25->P26: The leaked cargo has been cleaned up;

[0076] P26->T22: Repair the container with cargo leakage;

[0077] T22->P21: The container with cargo leakage has been repaired and the container sealing is intact;

[0078] P21->T22: The container is sealed and the cargo is intact;

[0079] T23->P24: Non-hazardous goods leakage;

[0080] P24->T26: No evacuation of yard personnel is carried out, and yard staff clean up the leaked cargo;

[0081] T26->P26: Container cargo leaks, and yard staff completes cleaning of leaked cargo;

[0082] Step S124: define token:

[0083] Initial token: P21 has a token, indicating that the initial state of the container is intact and sealed. After the transition occurs, the token of the corresponding place will change.

[0084] Furthermore, the subsequent steps of step S13 are as follows:

[0085] Step S131: define the library:

[0086] P31: The entrance to the field is unobstructed;

[0087] P32: Container trucks parked at the yard entrance;

[0088] P33: Container truck unloading / loading;

[0089] P34: Container truck leaves;

[0090] P35: Yard traffic diversion;

[0091] P36: The yard has smooth traffic;

[0092] Step S132: Define transitions:

[0093] T31: Container truck arrives at the yard;

[0094] T32: Container trucks enter the yard;

[0095] T33: Container truck unloading / loading completed;

[0096] T34: Container trucks drive out of the yard exit;

[0097] T35: Yard traffic jam;

[0098] T36: The yard traffic was successfully diverted;

[0099] Step S133: Define directed edges:

[0100] T31->P32: After the container truck arrives at the yard, it stops at the yard entrance;

[0101] P32->T32: Container trucks enter the yard from the yard entrance;

[0102] T32->P33: The container truck is in the yard and starts unloading / loading;

[0103] P33->T33: The container truck is in the yard, unloading / loading is completed;

[0104] T33->P34: The container truck is preparing to leave the yard;

[0105] P34->T34: The container truck leaves the yard from the yard exit;

[0106] T34->P36: The yard traffic is smooth;

[0107] P36->T31: No traffic accidents in the yard;

[0108] T31->P32: When the yard entrance traffic is clear, container trucks can enter the yard;

[0109] P32->T35: Traffic congestion at the yard entrance, traffic diversion is carried out;

[0110] T35->P35: Yard traffic diversion is in progress;

[0111] P35->T36: Yard traffic diversion completed;

[0112] T36->P36: The yard traffic is smooth;

[0113] T34->P31: The container is driven out from the yard exit, and the yard traffic is unobstructed;

[0114] Step S134: define token:

[0115] Initial Token: P31 has a token, indicating that the initial state of the yard entrance is smooth. After the transition occurs, the token of the corresponding place will change; P32 has a token, indicating that the initial state of the container truck is entering the yard entrance. After the transition occurs, the token of the corresponding place will change.

[0116] Furthermore, the specific steps of step S14 are as follows:

[0117] Step S141: define the library:

[0118] P41: Container storage area is free;

[0119] P42: Container arrival;

[0120] P43: Containers are being stacked;

[0121] P44: Container stacking completed;

[0122] P45: Container stacking is unstable;

[0123] P46: Container collapse;

[0124] P47: Collapse cleanup;

[0125] Step S142: Define transitions:

[0126] T41: Containers arrive and begin to be stacked;

[0127] T42: Container stacking is completed;

[0128] T43: Container stacking instability detection;

[0129] T44: Container collapse;

[0130] T45: Start clearing collapsed containers;

[0131] Step S143: Define directed edges:

[0132] P41->T41: When the stacking area is free, the container arrives and starts to be stacked;

[0133] T41->P42: container arrives;

[0134] P42->T42: Containers begin to be stacked;

[0135] T42->P43: Containers are being stacked;

[0136] P43->T43: Check container stacking stability;

[0137] T43->P44: Container stacking is complete and stable;

[0138] T43->P45: Container stacking is unstable;

[0139] P45->T44: Unstable container collapses;

[0140] T44->P46: Container collapse;

[0141] P46->T45: Start clearing the collapsed containers;

[0142] T45->P47: Cleaning in progress;

[0143] P47->T41: After the cleanup is completed, the stacking area returns to an idle state;

[0144] Step S144: define token:

[0145] Initial token: P41 has a token, which means the initial state of the stacking area is idle. After the transition occurs, the token of the corresponding place will change.

[0146] Furthermore, the specific steps of step S2 are as follows:

[0147] Step S21: Simulate and analyze the No. 1 petri net model;

[0148] Step S211: define a matrix with one row and seven columns, where each column represents P11, P12, P13, P14, P15, P16, and P17 from left to right. The matrix element value corresponding to P11 with a token is 1, and the matrix element values ​​corresponding to P12, P13, P14, P15, P16, and P17 without a token are 0.

[0149] Step S211 obtains the matrix 11 as: [1,0,0,0,0,0,0], matrix 11;

[0150] Step S212: the initial state P11 has a token, and the initial state P11 has two paths: P11->T11, T11->P12 and P11->T18, T18->P11. Therefore, the initial state P11 can choose to execute event T11 or event T18.

[0151] If the initial state P11 executes event T11, state P11 loses the token, and state P12 obtains the token. Matrix 12 is:

[0152] Matrix 12;

[0153] If the initial state P11 executes event T18, state P11 obtains the token, and matrix 12 is:

[0154] [1,0,0,0,0,0,0], matrix 12;

[0155] Step S213: State P12 has a token. P12 has only one path: P12->T12, T12->P13. State P12 can only execute event T12. Each time an event is executed, one row and seven columns are expanded on the basis of the original matrix 12, thereby obtaining the final matrix 18:

[0156] Matrix 18;

[0157] Step S214: From the path described in step S113 above, it can be seen that the probability of fire in the basic yard and the probability of no fire are 1 / 2; and because there is only one path without fire and there are 7 paths to avoid fire, the ratio of the probability of fire in the simulated yard to the probability of no fire is 1:7. Therefore, the result of the simulation analysis of the No. 1 petri net model is:

[0158] The probability of fire in the simulated storage yard is 1 / 2*1 / 8*100%=6.25%;

[0159] The probability that no fire occurs in the simulated storage yard is 1 / 2*(1+7 / 8)*100%=93.75%;

[0160] Step S22: Analyze the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model using the method of analyzing the No. 1 Petri net model in Step S211 to Step S214, and obtain;

[0161] Analysis results of the No. 2 Petri net model:

[0162] The probability of no leakage of cargo in the simulated yard is 1 / 2*(1+9 / 10)*100%=95%;

[0163] The probability of leakage of dangerous goods in the simulated storage yard is 5%*4 / 9*100%=2%;

[0164] The probability of non-cargo leakage in the simulated yard is 5%*(1+5 / 9)*100%=3%;

[0165] Analysis results of the No. 3 Petri net model:

[0166] The probability of simulated yard traffic accidents is 1 / 2*1 / 4*100%=12.5%;

[0167] The probability of non-traffic accidents in the simulated storage yard is 1 / 2*(1+3 / 4)*100%=87.5%;

[0168] Analysis results of the No. 4 Petri net model:

[0169] The probability that the simulated container yard will not collapse is 1 / 2*(1+5 / 8)*100%=82%;

[0170] The probability of container collapse in the simulated yard is 1 / 2*3 / 8*100%=18%;

[0171] Step S23: The analysis results of steps S21 to S22 are used as a primary analysis report of the storage yard risk.

[0172] Furthermore, the specific steps of step S3 are as follows:

[0173] Step S31: Obtain the historical operation records of the storage yard, and count the incidence rates of fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as a, b, c, d and e respectively;

[0174] Step S32: Count the historical operation records of the storage yard, and the time taken to solve the fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as ta, tb, tc, td and te respectively;

[0175] Step S33: Calculate the disaster weight of the storage yard;

[0176] The fire damage weight of the storage yard is AA, AA = 6.25% * 1 / a;

[0177] The disaster weight of the leakage of dangerous goods in the storage yard is BB, BB = 2% * 1 / b;

[0178] The weight of the non-dangerous goods leakage in the yard is CC, CC = 3% * 1 / c;

[0179] The weight of the traffic accident in the yard is DD, DD = 12.5% ​​* 1 / d;

[0180] The disaster weight of the container collapse accident in the yard is EE, EE = 18% * 1 / e;

[0181] Step S34: estimating the disaster delay time of the storage yard;

[0182] Yard fire delay time TA, TA = AA*1 / ta;

[0183] Delay time TB due to leakage of dangerous goods in the storage yard, TB = BB*1 / tb;

[0184] Delay time TC for leakage of non-dangerous goods in the storage yard, TC = CC*1 / tc;

[0185] Yard traffic accident delay time TD, TD = DD * 1 / td;

[0186] Delay time TE due to container collapse accident in the yard, TE = EE*1 / te;

[0187] Step S35: Compare the delay time of the storage yard affected by the disaster to obtain a risk analysis report of the storage yard;

[0188] If TA is the smallest, it means that the risk of fire in the yard is high;

[0189] If TB is the smallest, it means that the risk of leakage of dangerous goods in the yard is high;

[0190] If TC is the smallest, it means that the yard has a high risk of non-dangerous goods;

[0191] If TA is the smallest, it means that the risk of traffic accidents in the yard is high;

[0192] If TA is the smallest, it means that the risk of container collapse in the yard is high.

[0193] Compared with the prior art, the present invention has the following beneficial effects:

[0194] 1. Visual representation: The present invention can clearly present the various components in the system and the relationship between them in a graphical manner, which is conducive to intuitive understanding of the system structure and process, making the risk analysis process easier to understand.

[0195] 2. Dynamic simulation: The present invention can simulate the dynamic behavior of the system, helping users to better understand the operation of the system in emergency situations, and is conducive to predicting possible risk points; at the same time, the present invention provides a formal description method, which is conducive to accurate modeling and analysis of the system and avoids the influence of human subjective factors.

[0196] 3. Strong fault tolerance: The present invention has a certain degree of fault tolerance and simulates the dynamic behavior of the yard during operation, so that the behavior of the system under different circumstances can be predicted through simulation, thereby improving the accuracy of risk analysis and helping analysts to quickly discover problems or potential risks in system design and correct them.

[0197] 4. Applicable to complex systems: For complex emergency systems such as container yards, the Petri net model can describe the system structure and behavior more comprehensively, which is conducive to comprehensive risk analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0198] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0199] Figure 1 It is a schematic diagram of the process of the present invention;

[0200] Figure 2 This is a schematic diagram of a No. 1 Petri net model of the present invention;

[0201] Figure 3 This is a schematic diagram of the No. 2 Petri net model of the present invention;

[0202] Figure 4 It is a schematic diagram of the No. 3 Petri net model of the present invention;

[0203] Figure 5 It is a schematic diagram of the No. 4 Petri net model of the present invention. DETAILED DESCRIPTION

[0204] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0205] The risk analysis method of the yard emergency rescue system based on Petri net includes:

[0206] It should be noted that the "yard" in the present invention means a "container yard".

[0207] Step S1: constructing a No. 1 petri net model for yard fire analysis, a No. 2 petri net model for yard dangerous goods leakage analysis, a No. 3 petri net model for yard traffic accident analysis, and a No. 4 petri net model for yard container collapse analysis;

[0208] The specific steps of step S1 are as follows:

[0209] Step S11: Please refer to Figure 2 , construct the No. 1 petri net model for yard fire analysis;

[0210] Step S111: Define the place (P1):

[0211] P11: Container status is normal;

[0212] P12: Fire hazard exists;

[0213] P13: Fire monitoring started;

[0214] P14: Fire breaks out;

[0215] P15: Fire spread;

[0216] P16: Fire response initiated;

[0217] P17: Fire extinguished;

[0218] Step S112: Define transition (T1):

[0219] T11: Fire hazard development;

[0220] T12: Start fire monitoring;

[0221] T13: Fire detected;

[0222] T14: Fire spread;

[0223] T15: Initiate fire response;

[0224] T16: Fire extinguished;

[0225] T17: Return to normal state;

[0226] T18: No fire hazard;

[0227] Step S113: Define directed edges:

[0228] P11->T11: When the container is in normal condition, a fire hazard may occur; T11->P12: A fire hazard exists;

[0229] P12->T12: After detecting a fire hazard, fire monitoring is started;

[0230] T12->P13: Fire monitoring in progress;

[0231] P13->T13: After the fire monitoring is completed, confirm whether a fire has occurred; T13->P14: Fire occurs;

[0232] P14->T14: Fire spreads to other containers or areas;

[0233] T14->P15: Fire spreading;

[0234] P15->T15: After the fire spreads, fire response is initiated;

[0235] T15->P16: Fire response in progress;

[0236] P16->T16: The fire brigade puts out the fire;

[0237] T16->P17: The fire was put out;

[0238] P17->T17: Clean up the scene and return to normal;

[0239] T17->P11: The container area returns to normal;

[0240] P11->T18: When the container is in normal condition, there is no fire hazard;

[0241] T18->P11: Container area is in normal state;

[0242] Step S114: define token:

[0243] Initial token: P11 has a token, indicating that the initial state of the container area is normal. After a transition occurs, the token of the corresponding place will change. For example, after T11 occurs, the token of P11 decreases, and the token of P12 increases.

[0244] Step S12: Please refer to Figure 3, construct the No. 2 petri net model for the analysis of hazardous materials leakage in storage yard;

[0245] Step S121: Define the place (P2)

[0246] P21: The container is sealed intact;

[0247] P22: Container damaged;

[0248] P23: Leakage of dangerous goods;

[0249] P24: Leakage of non-dangerous goods;

[0250] P25: Evacuation of yard personnel;

[0251] P26: Cargo spill cleanup completed;

[0252] Step S122: Define transition (T2):

[0253] T21: Container cargo is damaged;

[0254] T22: Container cargo is intact;

[0255] T23: Cargo leakage inspection;

[0256] T24: Initiate emergency response;

[0257] T25: A dedicated person cleans up the leaked goods;

[0258] T26: Yard staff cleaned up the leaked cargo;

[0259] Step S123: Define directed edges:

[0260] P21->T21: When the container is sealed intact, cargo damage may occur;

[0261] T21->P22: Container damaged;

[0262] P22->T23: Check the damaged container for leaked cargo;

[0263] T23->P23: Dangerous goods leakage;

[0264] P23->T24: Initiate emergency response measures;

[0265] T24->P25: Dangerous goods leak, evacuate yard personnel;

[0266] P25->T25: The yard manager invites professionals to clean up the leak of dangerous goods;

[0267] T25->P26: The leaked cargo has been cleaned up;

[0268] P26->T22: Repair the container with cargo leakage;

[0269] T22->P21: The container with cargo leakage has been repaired and the container sealing is intact;

[0270] P21->T22: The container is sealed and the cargo is intact;

[0271] T23->P24: Non-hazardous goods leakage;

[0272] P24->T26: No evacuation of yard personnel is carried out, and yard staff clean up the leaked cargo;

[0273] T26->P26: Container cargo leaks, and yard staff completes cleaning of leaked cargo;

[0274] Step S124: define token:

[0275] Initial token: P21 has a token, indicating that the initial state of the container is intact. After a transition occurs, the token of the corresponding place will change. For example, after T21 occurs, the token of P21 decreases, and the token of P22 increases.

[0276] Step S13: Please refer to Figure 4 , construct the No. 3 petri net model for yard traffic accident analysis;

[0277] Step S131: Define the place (P3):

[0278] P31: The entrance to the field is unobstructed;

[0279] P32: Container trucks parked at the yard entrance;

[0280] P33: Container truck unloading / loading;

[0281] P34: Container truck leaves;

[0282] P35: Yard traffic diversion;

[0283] P36: The yard has smooth traffic;

[0284] Step S132: Define transition (T3):

[0285] T31: Container truck arrives at the yard;

[0286] T32: Container trucks enter the yard;

[0287] T33: Container truck unloading / loading completed;

[0288] T34: Container trucks drive out of the yard exit;

[0289] T35: Yard traffic jam;

[0290] T36: The yard traffic was successfully diverted;

[0291] Step S133: Define directed edges:

[0292] T31->P32: After the container truck arrives at the yard, it stops at the yard entrance;

[0293] P32->T32: Container trucks enter the yard from the yard entrance;

[0294] T32->P33: The container truck is in the yard and starts unloading / loading;

[0295] P33->T33: The container truck is in the yard, unloading / loading is completed;

[0296] T33->P34: The container truck is preparing to leave the yard;

[0297] P34->T34: The container truck leaves the yard from the yard exit;

[0298] T34->P36: The yard traffic is smooth;

[0299] P36->T31: No traffic accidents in the yard;

[0300] T31->P32: When the yard entrance traffic is clear, container trucks can enter the yard;

[0301] P32->T35: Traffic congestion at the yard entrance, traffic diversion is carried out;

[0302] T35->P35: Yard traffic diversion is in progress;

[0303] P35->T36: Yard traffic diversion completed;

[0304] T36->P36: The yard traffic is smooth;

[0305] T34->P31: The container is driven out from the yard exit, and the yard traffic is unobstructed;

[0306] Step S134: define token:

[0307] Initial Token: P31 has a token, which means that the initial state of the yard entrance is smooth. After the transition occurs, the token of the corresponding place will change. P32 has a token, which means that the initial state of the container truck is entering the yard entrance. After the transition occurs, the token of the corresponding place will change. For example, after T31 occurs, the token of P31 decreases and the token of P32 increases.

[0308] Step S14: Please refer to Figure 5 , construct the No. 4 petri net model for container collapse analysis in the yard; Step S141: define the library (P4):

[0309] P41: Container storage area is free;

[0310] P42: Container arrival;

[0311] P43: Containers are being stacked;

[0312] P44: Container stacking completed;

[0313] P45: Container stacking is unstable;

[0314] P46: Container collapse;

[0315] P47: Collapse cleanup;

[0316] Step S142: Define transition (T4):

[0317] T41: Containers arrive and begin to be stacked;

[0318] T42: Container stacking is completed;

[0319] T43: Container stacking instability detection;

[0320] T44: Container collapse;

[0321] T45: Start clearing collapsed containers;

[0322] Step S143: Define directed edges:

[0323] P41->T41: When the stacking area is free, the container arrives and starts to be stacked; T41->P42: The container arrives;

[0324] P42->T42: Containers begin to be stacked;

[0325] T42->P43: Containers are being stacked;

[0326] P43->T43: Check container stacking stability;

[0327] T43->P44: Container stacking is complete and stable;

[0328] T43->P45: Container stacking is unstable;

[0329] P45->T44: Unstable container collapses;

[0330] T44->P46: Container collapse;

[0331] P46->T45: Start clearing the collapsed containers;

[0332] T45->P47: Cleaning in progress;

[0333] P47->T41: After the cleanup is completed, the stacking area returns to an idle state;

[0334] Step S144: define token:

[0335] Initial token: P41 has a token, which means that the initial state of the stacking area is idle. After the transition occurs, the token of the corresponding place will change; for example, after T1 occurs, the token of P41 decreases and the token of P42 increases.

[0336] It should be noted that the No. 1 Petri net model, the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model in the present invention are all quintuples, namely {P, T, A, F, M0}, where: P is a finite set of places, indicating the state of the system; T is a finite set of transitions, indicating the actions that cause the system state to change; A is a set of arcs, which are directed arcs connecting places and transitions; F is an arc function, indicating the change of tokens in places when the system state changes; M0 is an initial identifier, indicating the number of token distributions in places in the initial state of the system.

[0337] Step S2: Perform a simulation analysis on the No. 1 Petri net model, the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model to obtain a primary analysis report on the storage yard risk;

[0338] The specific steps of step S2 are as follows:

[0339] Step S21: Simulate and analyze the No. 1 petri net model;

[0340] Step S211: define a matrix with one row and seven columns, where each column represents P11, P12, P13, P14, P15, P16, and P17 from left to right. The matrix element value corresponding to P11 with a token is 1, and the matrix element values ​​corresponding to P12, P13, P14, P15, P16, and P17 without a token are 0.

[0341] Step S211 obtains the matrix 11 as: [1,0,0,0,0,0,0], matrix 11;

[0342] Step S212: the initial state P11 has a token, and the initial state P11 has two paths: P11->T11, T11->P12 and P11->T18, T18->P11. Therefore, the initial state P11 can choose to execute event T11 or event T18.

[0343] If the initial state P11 executes event T11, state P11 loses the token, and state P12 obtains the token. Matrix 12 is:

[0344] Matrix 12;

[0345] If the initial state P11 executes event T18, state P11 obtains the token, and matrix 12 is:

[0346] [1,0,0,0,0,0,0], matrix 12;

[0347] Step S213: State P12 has a token, and P12 has only one path: P12->T12, T12->P13. State P12 can only execute event T12.

[0348] State P12 executes event T12, state P12 loses the token, state P13 obtains the token, and matrix 13 is:

[0349] Matrix 13;

[0350] Step S214: State P13 has a token, and there is only a single path from state P13 to state P17. Each time an event is executed, one row and seven columns are expanded on the basis of the original matrix 13.

[0351] State P13 executes event T13, and state P14 obtains token. Matrix 14 is:

[0352] Matrix 14;

[0353] State P14 executes event T14, and state P15 obtains the token. Matrix 15 is:

[0354] Matrix 15;

[0355] State P15 executes event T15, state P16 obtains token, and matrix 16 is:

[0356] Matrix16;

[0357] State P16 executes event T16, state P17 obtains token, and matrix 17 is:

[0358] Matrix 17;

[0359] Step S215: State P17 has a token. State P17 has only one path: P17->T17, T17->P11. State P17 can only execute event T17.

[0360] State P17 executes event T17, state P17 loses the token, state P11 obtains the token, and the entire system returns to the initial state, that is, the initial state P11 loses the token after various event changes; the system then undergoes time changes, and state P11 obtains the token;

[0361] State P17 executes event T17, state P17 loses the token, state P11 obtains the token, and matrix 18 is:

[0362] Matrix 18;

[0363] Step S216: From the above steps S211 to S212 and S211 to S215, it can be seen that there are two complete paths for the initial state P11 to return to the initial state P11 after the event transformation; steps S211 to S212 indicate that there is no fire in the yard; steps S211 to S215 indicate avoiding the occurrence of fire in the yard; therefore, the probability of fire in the basic yard and the probability of no fire are 1 / 2; and because there is only one path in steps S211 to S212; there are 7 paths in steps S211 to S215, so the ratio of the probability of fire in the simulated yard to the probability of no fire is: 1:7, so the result of the simulation analysis of the No. 1 petri net model is:

[0364] The probability of fire in the simulated storage yard is 1 / 2*1 / 8*100%=6%;

[0365] The probability that no fire occurs in the simulated storage yard is 1 / 2*(1+7 / 8)*100%=94%;

[0366] Step S22: performing simulation analysis on the No. 2 petri net model;

[0367] Step S221: define a matrix with one row and six columns, where each column represents P21, P22, P23, P24, P25, and P26 from left to right. The matrix element value corresponding to P21 with a token is 1, and the matrix element values ​​corresponding to P22, P23, P24, P25, and P26 without a token are 0.

[0368] Step S221 obtains the matrix 21 as: [1, 0, 0, 0, 0, 0], matrix 21;

[0369] Step S222: the initial state P21 has a token, and the initial state P21 has two paths: P21->T21, T21->P22 and P21->T22, T22->P21. Therefore, the initial state P21 can choose to execute event T11 or event T18.

[0370] If the initial state P21 executes event T21, state P21 loses the token, and state P22 obtains the token. Matrix 22 is:

[0371] Matrix 22;

[0372] If the initial state P21 executes event T22, state P21 obtains the token, and matrix 22 is:

[0373] [1,0,0,0,0,0], matrix 22;

[0374] Step S223: State P22 has a token. State P22 has two paths: P22->T23, T23->P23 and P22->T23, T23->P24. Therefore, state P22 can choose to reach state P23 or state P24.

[0375] If the initial state P22 reaches state P23, state P22 loses the token, and state P23 obtains the token. The matrix 23 is:

[0376] Matrix 23;

[0377] If the initial state P22 reaches the state P24, the state P22 loses the token, and the state P24 obtains the token, the matrix 23 is:

[0378] Matrix 23;

[0379] Step S224: State P23 has a token, and there is only a single path from state P23 to state P26. Each time an event is executed, one row and six columns are expanded on the basis of the original matrix 23.

[0380] State P23 executes event T24, state P25 obtains token, and matrix 24 is:

[0381] Matrix 24;

[0382] State P25 executes event T25, state P26 obtains token, and matrix 25 is:

[0383] Matrix 25;

[0384] Step S225: State P24 has a token, and state P23 has only one path: P24->T26, T26->P26. State P24 executes event T26, state P24 loses the token, and state P25 obtains the token. Another representation of matrix 25 is:

[0385] Matrix 25;

[0386] Step S226: State P26 has a token, and the post-path of state P26 is only P26->T22, T22->P21, but the pre-path is from state P23 to state P26 and from state P24 to state P26;

[0387] If the preceding path of state P26 is: state P23 to state P26, then state P26 executes event T22, and the corresponding matrix 26 is:

[0388] Matrix 26;

[0389] If the preceding path of state P26 is: state P24 to state P26, then state P26 executes event T22, and the corresponding matrix 26 is:

[0390] Matrix 26;

[0391] Step S227: From the above steps S221 to S222, steps S221 to S224 and S226, and steps S221 to S223 and S225 to S226, it can be known that there are three complete paths for the initial state P21 to return to the initial state P21 after the event transformation;

[0392] Steps S221 to S222 indicate that container cargo does not leak; steps S221 to S224 and S226 indicate avoiding leakage of dangerous container cargo; steps S221 to S223 and S225 to S226 indicate avoiding leakage of non-dangerous container cargo; therefore, the probability of no leakage of basic yard cargo and leakage of cargo is 1 / 2; the probability of cargo leakage is further divided into leakage of dangerous cargo and leakage of non-dangerous container, so the probabilities of no leakage of basic yard cargo, leakage of dangerous cargo and leakage of non-dangerous container are: 1 / 2, 1 / 4, 1 / 4;

[0393] Because there is only one path from step S221 to step S222; there are five paths from step S221 to step S224 and step S226; there are four paths from step S221 to step S223 and step S225 to step S226; therefore, the ratio of the probability of cargo leakage to cargo non-leakage in the simulated yard is: 1:9;

[0394] The probability of no leakage of cargo in the simulated yard is 1 / 2*(1+9 / 10)*100%=95%;

[0395] The probability of cargo leakage in the simulated yard is 1 / 2*1 / 10*100%=5%;

[0396] Therefore, the ratio of the probability of dangerous goods leakage to non-goods leakage in the simulated storage yard is: 4:5;

[0397] The probability of leakage of dangerous goods in the simulated storage yard is 5%*4 / 9*100%=2%;

[0398] The probability of non-cargo leakage in the simulated yard is 5%*(1+5 / 9)*100%=3%;

[0399] Step S23: performing simulation analysis on the No. 3 petri net model;

[0400] Step S231: define a matrix with one row and six columns, where each column represents P31, P32, P33, P34, P35, and P36 from left to right. The matrix element values ​​corresponding to P31 and P32 with tokens are 1, and the matrix element values ​​corresponding to P33, P34, P35, and P36 without tokens are 0.

[0401] Step S231 obtains the matrix 31 as: [1,1,0,0,0,0], matrix 31;

[0402] Step S232: the initial state P32 has a token, and the initial state P32 has two paths: P32->T32, T32->P33 and P32->T35, T35->P35. Therefore, the initial state P32 can choose to execute event T32 or event T35.

[0403] If the initial state P32 executes event T32, state P32 loses the token and state P33 obtains the token; at the same time, the initial state P31 transfers the token to state P33, and state P33 has two token matrices 31:

[0404] Matrix 31;

[0405] If the initial state P32 executes event T35, state P32 loses the token, and state P35 obtains the token, and matrix 31 is:

[0406] Matrix 31;

[0407] Step S233: State P33 has a token, and state P33 has only one path: P33->T33, T33->P34. State P33 can only execute event T33.

[0408] State P33 executes event T33, state P33 loses 2 tokens, state P34 gains 2 tokens, and matrix 32 is:

[0409] Matrix32;

[0410] Step S234: State P35 has a token, and state P35 has only one path: P35->T36, T36->P36. State P35 can only execute event T36.

[0411] State P35 executes event T36. State P35 loses 2 tokens, and state P36 gains 2 tokens. Another representation of matrix 32 is:

[0412] Matrix32;

[0413] Step S235: State P34 has a token. State P34 has only one path: P34->T34, T34->P36. State P34 can only execute event T34.

[0414] State P34 executes event T34. State P34 loses 2 tokens, state P31 obtains 1 token, and state P36 obtains a token. Matrix 33 is:

[0415] Matrix 33;

[0416] Step S236: State P36 has a token, but the preceding paths of state P36 include P34->T34, T34->P36 and P35->T36, T36->P36, while the following path of state P36 includes only one path: P36->T31, T31->P32.

[0417] If the preceding path of state P36 is: P34->T34, T34->P36, then state P36 executes T31, and the corresponding matrix 34 is:

[0418] Matrix 34;

[0419] If the preceding path of state P36 is: P35->T36, T36->P36, then state P36 executes T31, and the corresponding matrix 34 is:

[0420] Matrix 34;

[0421] Step S237: From steps S231 to S232, S233, S235 to S236, S231 to S232, S234 and S236, it can be seen that there are two complete paths for the initial state P31 to return to the initial state P31 after the event transformation;

[0422] Steps S231 to S232, S233, S235 to S236 indicate that the yard avoids traffic accidents; S231 to S232, S234 and S236 indicate that no traffic accidents occur in the yard, so the probability of traffic accidents and no congestion in the basic yard is 1 / 2;

[0423] Because there are 4 paths from step S231 to step S232, step S233, and step S235 to step S236, and there are 3 paths from step S231 to step S232, step S234, and step S236, the ratio of the probability of traffic accidents and no congestion in the simulated yard is 3:4;

[0424] In addition, in the corresponding paths of steps S231 to S232, S233, S235 to S236, the tokens of initial state P31 and initial state P32 both participate in the state change; while in S231 to S232, S234, and S236, only initial state P32 participates in the state change; therefore, the ratio of the probability of traffic accident and no congestion in the simulated yard is 1:3;

[0425] The probability of simulated yard traffic accidents is 1 / 2*1 / 4*100%=12%;

[0426] The probability of non-traffic accidents in the simulated storage yard is 1 / 2*(1+3 / 4)*100%=88;

[0427] Step S24: performing simulation analysis on the No. 4 petri net model;

[0428] Step S241: define a matrix with one row and seven columns, where each column represents P41, P42, P43, P44, P45, P46, and P47 from left to right. The matrix element value corresponding to P41 with a token is 1, and the matrix element values ​​corresponding to P42, P43, P44, P45, P46, and P47 without a token are 0.

[0429] Step S241 obtains the matrix 41 as: [1, 0, 0, 0, 0, 0], matrix 41;

[0430] Step S242: Initial state P41 has a token, and there is only a single path from initial state P41 to state P43. Each time an event is executed, one row and seven columns are expanded on the basis of the original matrix 41.

[0431] Initial state P41 executes event T41, state P42 obtains token, matrix 42:

[0432] Matrix 42;

[0433] State P42 executes event T42, state P43 obtains token, matrix 43:

[0434] Matrix 43;

[0435] Step S243: State P43 has a token, and state P43 has two paths: P43->T43, T43->P44 and P43->T43, T43->P45;

[0436] If state P43 executes event T43 and reaches state P44, the corresponding matrix 44 is:

[0437] Matrix 44;

[0438] If state P43 executes event T43 and reaches state P45, the corresponding matrix 44 is:

[0439] Matrix 44;

[0440] Step S244: because the initial state P41 indicates that the yard is idle and the state P44 indicates that the container is stacked, the state P44 is a steady state and no subsequent operation is required;

[0441] State P45 indicates that the stacking of containers is unstable and not in a steady state, and subsequent operations are required; State P45 has a token, and there is only a single path from state P45 to state P47. Each time an event is executed, a row and seven columns are expanded on the basis of the matrix 44 corresponding to the original state P45;

[0442] State P45 executes event T44, state P46 obtains token, matrix 45:

[0443] Matrix 45;

[0444] State P46 executes event T45, state P47 obtains token, matrix 46:

[0445] Matrix 46;

[0446] Step S245: From the definition of steps S241 to S243, steps S241 to S243 and step S244 and the initial state P41, it can be known that state P44 is a steady state, and the initial state P41 cannot return to the initial state after the event transformation; therefore, there is only one complete path leading to the steady state, but there are two choices; therefore, the probability value of the container not collapsing in the yard and the container collapsing is 1 / 2;

[0447] Steps S241 to S243 indicate that the container has not collapsed and there are three paths;

[0448] Steps S241 to S243 and S244 indicate avoiding container collapse, and there are 5 paths;

[0449] And because the probability of state P43 transforming into state P44 and state P45 is the same, the ratio of the probability of no container collapse and container collapse in the simulated yard satisfies 5:3;

[0450] The probability that the simulated container yard will not collapse is 1 / 2*(1+5 / 8)*100%=82%;

[0451] The probability of container collapse in the simulated yard is 1 / 2*3 / 8*100%=18%;

[0452] Step S25: The analysis results of steps S21 to S24 are used as a primary analysis report of the storage yard risk.

[0453] Step S3: Obtain the historical operation records of the storage yard, count and calculate the disaster weight of the storage yard; conduct a secondary analysis on the primary risk analysis report of the storage yard in combination with the disaster weight to obtain a risk analysis report of the storage yard;

[0454] The specific steps of step S3 are as follows:

[0455] Step S31: Obtain the historical operation records of the storage yard, and count the incidence rates of fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as a, b, c, d and e respectively;

[0456] Step S32: Count the historical operation records of the storage yard, and the time taken to solve the fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as ta, tb, tc, td and te respectively;

[0457] Step S33: Calculate the disaster weight of the storage yard;

[0458] The yard fire damage weight AA, AA = 6% * 1 / a, 6% comes from step S216;

[0459] The weight of the disaster of leakage of dangerous goods in the storage yard is BB, BB=2%*1 / b, 2% comes from step S227;

[0460] The weight of the non-dangerous goods leakage in the yard CC, CC = 3% * 1 / c, 3% comes from step S227;

[0461] The yard traffic accident damage weight DD, DD = 12% * 1 / d, 12% comes from step S237;

[0462] The weight of the container collapse accident in the yard is EE, EE=18%*1 / e, 18% comes from step S245;

[0463] Step S34: estimating the disaster delay time of the storage yard;

[0464] Yard fire delay time TA, TA = AA*1 / ta;

[0465] Delay time TB due to leakage of dangerous goods in the storage yard, TB = BB*1 / tb;

[0466] Delay time TC for leakage of non-dangerous goods in the storage yard, TC = CC*1 / tc;

[0467] Yard traffic accident delay time TD, TD = DD * 1 / td;

[0468] Delay time TE due to container collapse accident in the yard, TE = EE*1 / te;

[0469] Step S35: Compare the delay time of the storage yard affected by the disaster to obtain a risk analysis report of the storage yard;

[0470] If TA is the smallest, it means that the risk of fire in the yard is high and fire prevention should be strengthened;

[0471] If TB is the smallest, it means that the risk of leakage of dangerous goods in the yard is high, and disinfection facilities should be added;

[0472] If TC is the smallest, it means that the yard has a high risk of non-dangerous goods, and container protection should be strengthened;

[0473] If TA is the smallest, it means that the risk of traffic accidents in the yard is high, and attention should be paid to traffic prevention;

[0474] If TA is the smallest, it means that the risk of container collapse in the yard is high and the container stacking height should be reduced.

[0475] It should be noted that, in the parts of the present invention involving numerical calculations, the calculation results are integers.

[0476] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technical personnel in this field according to actual conditions. For example, if there are weight coefficients and proportional coefficients, their set sizes are to quantify each parameter to obtain a specific value, which is convenient for subsequent comparison. Regarding the size of the weight coefficient and the proportional coefficient, it is sufficient as long as it does not affect the proportional relationship between the parameter and the quantized value.

[0477] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A risk analysis method for a storage yard emergency rescue system based on petri nets, characterized in that: Analytical methods include: Step S1: constructing a No. 1 petri net model for yard fire analysis, a No. 2 petri net model for yard dangerous goods leakage analysis, a No. 3 petri net model for yard traffic accident analysis, and a No. 4 petri net model for yard container collapse analysis; The steps of constructing the No. 1 Petri net model for yard fire analysis are as follows: Define the library place: P11: Container status is normal; P12: Fire hazard exists; P13: Fire monitoring started; P14: Fire occurs; P15: Fire spread; P16: Fire response initiated; P17: Fire extinguished; Definition changes: T11: Fire hazard development; T12: Start fire monitoring; T13: Fire detected; T14: Fire spread; T15: Initiate fire response; T16: Fire extinguished; T17: Return to normal state; T18: No fire hazard; Define a directed edge: P11->T11: When the container is in normal condition, a fire hazard occurs; T11->P12: Fire hazard exists; P12->T12: After detecting a fire hazard, fire monitoring is started; T12->P13: Fire monitoring in progress; P13->T13: After the fire monitoring is completed, confirm whether a fire has occurred; T13->P14: Fire occurs; P14->T14: Fire spreads to other containers or areas; T14->P15: Fire spreading; P15->T15: After the fire spreads, fire response is initiated; T15->P16: Fire response in progress; P16->T16: The fire brigade puts out the fire; T16->P17: The fire was put out; P17->T17: Clean up the scene and return to normal; T17->P11: The container area returns to normal; P11->T18: When the container is in normal condition, there is no fire hazard; T18->P11: Container area is in normal state; Define a token: Initial token: P11 has a token, indicating that the initial state of the container area is normal. After the transition occurs, the token of the corresponding place will change, and the process goes to step S2. Step S2: Perform a simulation analysis on the No. 1 Petri net model, the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model to obtain a primary analysis report on the storage yard risk; Step S3: Obtain the historical operation records of the storage yard, count and calculate the disaster weight of the storage yard; conduct a secondary analysis on the primary risk analysis report of the storage yard in combination with the disaster weight to obtain a risk analysis report of the storage yard; The specific steps of step S2 are as follows: Step S21: Simulate and analyze the No. 1 petri net model; Step S211: define a matrix with one row and seven columns, where each column represents P11, P12, P13, P14, P15, P16, and P17 from left to right. The matrix element value corresponding to P11 with a token is 1, and the matrix element values ​​corresponding to P12, P13, P14, P15, P16, and P17 without a token are 0. Step S211 obtains the matrix 11 as: , matrix 11; Step S212: the initial state P11 has a token, and the initial state P11 has two paths: P11->T11, T11->P12 and P11->T18, T18->P11. Therefore, the initial state P11 can choose to execute event T11 or event T18. If the initial state P11 executes event T11, the initial state P11 loses the token, and the state P12 obtains the token. The matrix 12 is: , matrix 12; If the initial state P11 executes event T18, the initial state P11 obtains the token, and the matrix 12 is: , matrix 12; Step S213: State P12 has a token. P12 has only one path: P12->T12, T12->P13. State P12 can only execute event T12. Each time an event is executed, one row and seven columns are expanded on the basis of the original matrix 12, thereby obtaining the final matrix 18: , matrix 18; Step S214: From the path described in step S213 above, it can be seen that the probability of fire in the basic yard and the probability of no fire are 1 / 2; and because there is only one path without fire and there are 7 paths to avoid fire, the ratio of the probability of fire in the simulated yard to the probability of no fire is 1:

7. Therefore, the result of the simulation analysis of the No. 1 petri net model is: The probability of fire in the simulated storage yard is 1 / 2*1 / 8*100%=6.25%; The probability that no fire occurs in the simulated storage yard is 1 / 2*(1+7 / 8)*100%=93.75%; Step S22: Analyze the No. 2 Petri net model, the No. 3 Petri net model and the No. 4 Petri net model using the method of analyzing the No. 1 Petri net model in Step S211 to Step S214, and obtain; Analysis results of the No. 2 Petri net model: The probability of no leakage of cargo in the simulated yard is 95%; The probability of leakage of dangerous goods in the simulated storage yard is 2%; The probability of non-cargo leakage in the simulated yard is 3%; Analysis results of the No. 3 Petri net model: The probability of simulated yard traffic accidents is 12.5%; The probability of non-traffic accidents in the simulated yard is 87.5%; Analysis results of the No. 4 Petri net model: The probability of no container collapse in the simulated yard is 82%; The probability of container collapse in the simulated yard is 18%; Step S23: taking the analysis results of steps S21 to S22 as a primary analysis report of the storage yard risk; The specific steps of step S3 are as follows: Step S31: Obtain the historical operation records of the storage yard, and count the incidence rates of fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as a, b, c, d and e respectively; Step S32: Count the historical operation records of the storage yard, and the time taken to solve the fire, dangerous goods leakage, non-dangerous goods leakage, traffic accidents and container collapse accidents in the storage yard in the past three years; record them as ta, tb, tc, td and te respectively; Step S33: Calculate the disaster weight of the storage yard; The fire damage weight of the storage yard is AA, AA = 6.25%*1 / a; The disaster weight of the leakage of dangerous goods in the storage yard is BB, BB = 2%*1 / b; The disaster weight of non-dangerous goods leakage in the yard CC, CC = 3%*1 / c; The weight of the traffic accident in the yard is DD, DD = 12.5%*1 / d; The disaster weight of the container collapse accident in the yard is EE, EE = 18%*1 / e; Step S34: estimating the disaster delay time of the storage yard; Yard fire delay time TA, TA = AA*1 / ta; Delay time TB due to leakage of dangerous goods in the storage yard, TB = BB*1 / tb; Delay time TC for leakage of non-dangerous goods in the storage yard, TC = CC*1 / tc; Yard traffic accident delay time TD, TD = DD * 1 / td; Delay time TE due to container collapse accident in the yard, TE = EE*1 / te; Step S35: Compare the delay time of the storage yard affected by the disaster to obtain a risk analysis report of the storage yard; If TA is the smallest, it means that the risk of fire in the yard is high; If TB is the smallest, it means that the risk of leakage of dangerous goods in the yard is high; If TC is the smallest, it means that the yard has a high risk of non-dangerous goods; If TA is the smallest, it means that the risk of traffic accidents in the yard is high; If TA is the smallest, it means that the risk of container collapse in the yard is high.

2. The risk analysis method for the storage yard emergency rescue system based on petri net according to claim 1 is characterized in that: The specific steps of step S1 are as follows: Step S11: constructing a No. 1 petri net model for yard fire analysis; Step S12: constructing a No. 2 petri net model for analyzing leakage of dangerous goods in a storage yard; Step S13: constructing a No. 3 petri net model for yard traffic accident analysis; Step S14: constructing a No. 4 petri net model for container collapse analysis in a yard.

3. The risk analysis method for the storage yard emergency rescue system based on petri net according to claim 2 is characterized in that: The specific steps of step S12 are as follows: Step S121: define the library: P21: The container is sealed intact; P22: Container damaged; P23: Leakage of dangerous goods; P24: Leakage of non-dangerous goods; P25: Evacuation of yard personnel; P26: Cargo spill cleanup completed; Step S122: define transition: T21: Container cargo is damaged; T22: Container cargo is intact; T23: Cargo leakage inspection; T24: Initiate emergency response; T25: A dedicated person cleans up the leaked goods; T26: Yard staff cleaned up the leaked cargo; Step S123: Define directed edges: P21->T21: cargo damage occurs when the container is sealed intact; T21->P22: Container damaged; P22->T23: Check the damaged container for leaked cargo; T23->P23: Dangerous goods leakage; P23->T24: Initiate emergency response measures; T24->P25: Dangerous goods leak, evacuate yard personnel; P25->T25: The yard manager invites professionals to clean up the leak of dangerous goods; T25->P26: The leaked cargo has been cleaned up; P26->T22: Repair the container with cargo leakage; T22->P21: The container with cargo leakage has been repaired and the container sealing is intact; P21->T22: The container is sealed and the cargo is intact; T23->P24: Non-hazardous goods leakage; P24->T26: No evacuation of yard personnel is carried out, and yard staff clean up the leaked cargo; T26->P26: Container cargo leaks, and yard staff completes cleaning of leaked cargo; Step S124: define token: Initial token: P21 has a token, indicating that the initial state of the container is intact and sealed. After the transition occurs, the token of the corresponding place will change.

4. The risk analysis method for the storage yard emergency rescue system based on petri net according to claim 2 is characterized in that: The subsequent steps of step S13 are as follows: Step S131: define the library: P31: The entrance to the field is unobstructed; P32: Container trucks parked at the yard entrance; P33: Container truck unloading / loading; P34: Container truck leaves; P35: Yard traffic diversion; P36: The yard has smooth traffic; Step S132: Define transitions: T31: Container truck arrives at the yard; T32: Container trucks enter the yard; T33: Container truck unloading / loading completed; T34: Container trucks drive out of the yard exit; T35: Yard traffic jam; T36: The yard traffic was successfully diverted; Step S133: Define directed edges: T31->P32: After the container truck arrives at the yard, it stops at the yard entrance; P32->T32: Container trucks enter the yard from the yard entrance; T32->P33: The container truck is in the yard and starts unloading / loading; P33->T33: The container truck is in the yard, unloading / loading is completed; T33->P34: The container truck is preparing to leave the yard; P34->T34: The container truck leaves the yard from the yard exit; T34->P36: The yard traffic is smooth; P36->T31: No traffic accidents in the yard; T31->P32: When the yard entrance traffic is clear, container trucks can enter the yard; P32->T35: Traffic congestion at the yard entrance, traffic diversion is carried out; T35->P35: Yard traffic diversion is in progress; P35->T36: Yard traffic diversion completed; T36->P36: The yard traffic is smooth; T34->P31: The container is driven out from the yard exit, and the yard traffic is unobstructed; Step S134: define token: Initial Token: P31 has a token, indicating that the initial state of the yard entrance is smooth. After the transition occurs, the token of the corresponding place will change; P32 has a token, indicating that the initial state of the container truck is entering the yard entrance. After the transition occurs, the token of the corresponding place will change.

5. The risk analysis method for the storage yard emergency rescue system based on petri net according to claim 2 is characterized in that: The specific steps of step S14 are as follows: Step S141: define the library: P41: Container storage area is free; P42: Container arrival; P43: Containers are being stacked; P44: Container stacking completed; P45: Container stacking is unstable; P46: Container collapse; P47: Collapse cleanup; Step S142: Define transitions: T41: Containers arrive and begin to be stacked; T42: Container stacking is completed; T43: Container stacking instability detection; T44: Container collapse; T45: Start clearing collapsed containers; Step S143: Define directed edges: P41->T41: When the stacking area is free, the container arrives and starts to be stacked; T41->P42: Container arrives; P42->T42: Containers begin to be stacked; T42->P43: Containers are being stacked; P43->T43: Check container stacking stability; T43->P44: Container stacking is complete and stable; T43->P45: Container stacking is unstable; P45->T44: Unstable container collapses; T44->P46: Container collapse; P46->T45: Start clearing the collapsed containers; T45->P47: Cleaning in progress; P47->T41: After the cleanup is completed, the stacking area returns to an idle state; Step S144: define token: Initial token: P41 has a token, which means the initial state of the stacking area is idle. After the transition occurs, the token of the corresponding place will change.

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