A highland complex geological tunnel harmful gas risk multi-factor dynamic evaluation method, system, device and storage medium

Abstract

The application discloses a kind of plateau complex geology tunnel harmful gas risk multi-factor dynamic evaluation method, system, equipment and storage medium. Plateau railway tunnel engineering construction often passes through extremely complex region of geological structure. The application constructs the GECA evaluation index system of fusion geological structure gas control nature G, gas occurrence characteristics E, construction disturbance effect C, plateau environment effect A;Using combination weighting method to determine the weight of each level index;According to geological survey, field test and construction record, obtain the original parameter and assignment of this paragraph, calculate the comprehensive risk value R of evaluation object;According to the comprehensive risk value R, determine the risk level;With construction progress, use advanced geological forecast and real-time monitoring data to dynamically update index parameters, re-execute step three, step four, realize the dynamic tracking and early warning of risk. The application realizes the accurate, dynamic quantitative evaluation of risk, and provides decision support for plateau tunnel safety construction.

Description

Technical Field

[0001] This invention belongs to the field of tunnel and underground engineering safety technology, specifically relating to a method, system, equipment and storage medium for dynamic evaluation of multi-factor risks of harmful gases in complex geological tunnels on plateaus. Background Technology

[0002] The construction of railway tunnels in high-altitude areas often traverses regions with extremely complex geological structures, facing serious threats from harmful gases such as methane (CH4), carbon dioxide (CO2), and hydrogen sulfide (H2S). Traditional evaluation methods (such as the "Technical Specification for Railway Gas Tunnels" TB10120-2019) mainly rely on absolute gas emission and tunnel span for static classification, which has significant shortcomings: 1) The evaluation indicators are singular, neglecting key factors such as the gas control properties of geological structures and gas occurrence characteristics; 2) The unique impact of the low-pressure and low-oxygen environment of high-altitude areas on gas migration and accumulation patterns is not considered, resulting in the failure to quantify effects such as reduced ventilation efficiency and changes in explosion limits; 3) The static evaluation model is difficult to adapt to dynamic risk changes during construction. Therefore, there is an urgent need for a method and system that can comprehensively consider multiple factors such as geology, gas, construction, and the high-altitude environment, and can conduct dynamic risk assessment. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention provides a method, system, equipment, and storage medium for dynamic evaluation of the risk of harmful gases in tunnels with complex geological conditions on plateaus, enabling accurate and dynamic quantitative evaluation of risks and providing decision support for safe construction of tunnels on plateaus.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A multi-factor dynamic evaluation method for hazardous gas risk in tunnels with complex geological conditions on plateaus includes the following steps:

[0006] Step 1: Construct a GECA evaluation index system that integrates geological structure gas control (G), gas occurrence characteristics (E), construction disturbance effect (C), and plateau environmental effect (A). The GECA evaluation index system includes four primary indicators: geological structure gas control (G); gas occurrence characteristics (E); construction disturbance effect (C); and plateau environmental effect (A).

[0007] Step 2: Determine the weights of indicators at each level using a combined weighting method;

[0008] Step 3: Based on geological surveys, field tests, and construction records, obtain the original parameters and values ​​for this section, and calculate the comprehensive risk value R of the evaluation object;

[0009] Step 4: Determine the risk level based on the comprehensive risk value R;

[0010] Step 5: As construction progresses, dynamically update the indicator parameters using advanced geological forecasts and real-time monitoring data, and re-execute Steps 3 and 4 to achieve dynamic tracking and early warning of risks.

[0011] Furthermore, step one specifically includes:

[0012] 1) Geological structure controls gas production (G)

[0013] It includes four secondary indicators: structural complexity G1; stratigraphic lithology combination G2; geostress field characteristics G3; and hydrogeological conditions G4.

[0014] ①Construction complexity G1

[0015] Includes two tertiary indicators: fracture density G 11 and wrinkle strength G 12 ;

[0016] Fracture density: >3 fractures / km², score 10; 1-3 fractures / km², score 6; 0-1 fractures / km², score 1.

[0017] Fold strength: Fold curvature radius < 5km, score 8 points; fold curvature radius 5-10km, score 4 points; fold curvature radius > 10km, score 1 point;

[0018] ② Stratigraphic lithology combination G2

[0019] Includes two tertiary indicators: coal-bearing strata thickness G 21 Top plate sealing G 22 ;

[0020] Coal-bearing strata thickness: >3.5m, score 10; 1.3-3.5m, score 6; <1.3m, score 1.

[0021] Roof sealing: Mudstone > 10m, score 10; Sandstone-mudstone interbedded, score 6; Sandstone predominant, score 1;

[0022] ③ Characteristics of the geostress field G3

[0023] Includes two tertiary indicators: the magnitude of geostress G. 31 Stress concentration degree G 32 ;

[0024] Ground stress magnitude: >25MPa, score 8 points; 15-25MPa, score 5 points; <15MPa, score 2 points;

[0025] Stress concentration level: Stress concentration factor > 1.5, score 8 points; Stress concentration factor 1.2-1.5, score 5 points; Stress concentration factor < 1.2, score 2 points;

[0026] ④ Hydrogeological conditions G4

[0027] Includes one tertiary indicator: groundwater activity G 41 ;

[0028] Groundwater permeability coefficient >10 -5 m / s, score 8 points; groundwater permeability coefficient 10 -6 -10 -5 m / s, score 5 points; groundwater permeability coefficient <10 -6 m / s, rating 2 points;

[0029] 2) Gas occurrence characteristics E

[0030] It includes four secondary indicators: gas concentration level E1; gas pressure E2; gas origin type E3; and emission form E4.

[0031] ① Gas concentration level E1

[0032] Includes three tertiary indicators: CH4 concentration E 11 H2S concentration E 12 and CO2 concentration E 13 ;

[0033] CH4 concentration: >10000ppm, score 10; 1000-10000ppm, score 6; <1000ppm, score 1.

[0034] H2S concentration: >20ppm, score 10; 10-20ppm, score 6; <10ppm, score 1.

[0035] CO2 concentration: >5000ppm, score 10; 1000-5000ppm, score 6; <1000ppm, score 1.

[0036] ②Gas pressure E2

[0037] Includes one tertiary indicator: gas pressure E 21 ;

[0038] Gas pressure >0.74MPa, score 10; 0.5-0.74MPa, score 6; <0.5MPa, score 1.

[0039] ③ Gas origin type E3

[0040] Includes one tertiary indicator: causal discrimination E 31 ;

[0041] Inorganic origin, score 8 points; mixed origin, score 5 points; organic origin, score 2 points;

[0042] ④ Outflow Form E4

[0043] Includes one tertiary indicator: Outflow characteristic E 41

[0044] A gas outburst velocity fluctuation coefficient δ > 0.6 earns a score of 10; a gas outburst velocity fluctuation coefficient δ between 0.3 and 0.6 earns a score of 5; and a gas outburst velocity fluctuation coefficient δ < 0.3 earns a score of 1.

[0045] 3) Construction disturbance effect C

[0046] It includes three secondary indicators: excavation process (C1); ventilation condition (C2); and support measures (C3).

[0047] ① Excavation process C1

[0048] Includes two tertiary indicators: tunneling speed C 11 Excavation section C 12 ;

[0049] Tunneling speed: >5m / d, score 8 points; 3-5m / d, score 5 points; <3m / d, score 2 points;

[0050] Excavation cross-section: >150m², score 8 points; 100-150m², score 5 points; <100m², score 2 points;

[0051] ②Ventilation status C2

[0052] Includes two tertiary indicators: air volume adequacy C 21 Distance C between the duct and the working face 22 ;

[0053] Airflow adequacy: <60% of demand, score 10; 60-80%, score 6; >80%, score 1.

[0054] Distance between air duct and working face: >15m, score 8 points; 10-15m, score 5 points; <10m, score 2 points;

[0055] ③Support measures C3

[0056] Includes two tertiary indicators: support timeliness C 31 Airtightness measures C 32 ;

[0057] Support timeliness: Delay > 2 cycles, score 8 points; Delay 1-2 cycles, score 5 points; Timely support, score 2 points;

[0058] Air tightness measures: Lining permeability coefficient K > 10⁻ 9 m / s, score 8 points; lining permeability coefficient 10 -10m / s≤K≤10⁻ 9 m / s, score 5 points; lining permeability coefficient K<10 -10 m / s, rating 2 points;

[0059] 4) Plateau environmental effects A

[0060] It includes three secondary indicators: altitude (A1); atmospheric conditions (A2); and climate characteristics (A3).

[0061] ① Altitude A1

[0062] Includes one tertiary indicator: Altitude Value A 11

[0063] Altitude: >4000m, score 10; 3000-4000m, score 6; <3000m, score 1.

[0064] ②Atmospheric conditions A2

[0065] Includes two tertiary indicators: atmospheric pressure A 21 Oxygen content A 22 ;

[0066] Atmospheric pressure: <61kPa, score 8; 61-70kPa, score 5; >70kPa, score 2;

[0067] Oxygen content: <18%, score 8 points; 18-20%, score 5 points; >20%, score 2 points;

[0068] ③Climate characteristics A3

[0069] Includes two tertiary indicators: temperature change A 31 Wind speed affects A 32 ;

[0070] Daily temperature range: >20℃, score 8 points; 10-20℃, score 5 points; <10℃, score 2 points;

[0071] Wind speed impact: Annual average wind speed at the tunnel entrance >6m / s, score 8 points; annual average wind speed at the tunnel entrance 3~6m / s, score 5 points; annual average wind speed at the tunnel entrance <3m / s, score 2 points.

[0072] Furthermore, step two specifically involves:

[0073] Step 2.1: Determine the subjective weights W using the Analytic Hierarchy Process (AHP). AHP,j ;

[0074] Step 2.2: Determine the objective weight W based on the field measurement data using the entropy weight method. EVM,j ;

[0075] Step 2.3: Final combined weight W j Through formula Calculate, where W j α represents the final combined weight of the j-th indicator; α is the preference coefficient.

[0076] Furthermore, in step four, the method for determining the risk level is as follows:

[0077] 1) Level I: Extremely high risk, R≥85; Level I is divided into: I-A, R≥90; I-B, 85≤R<90;

[0078] 2) Level II: High risk, 70≤R<85; Level II is divided into: II-A, 80≤R<85; II-B, 75≤R<80; II-C, 70≤R<75;

[0079] 3) Level III: Medium risk, 55≤R<70; Level III is divided into: III-A, 65≤R<70; III-B, 60≤R<65; III-C, 55≤R<60;

[0080] 4) Level IV: Low risk, R<55; Level IV is divided into: IV-A, 45≤R<55; IV-B, 30≤R<45; IV-C, R<30.

[0081] Furthermore, the quantification of the plateau environmental effect A includes using a modified formula for the explosion limit of combustible gases based on the low atmospheric pressure at high altitudes:

[0082] Explosion lower limit correction formula:

[0083] Explosion limit correction formula:

[0084] Where LEL is the lower explosive limit concentration of combustible gas (%); UEL is the upper explosive limit concentration of combustible gas (%); and P is atmospheric pressure (MPa).

[0085] Furthermore, in step five, the dynamic update is triggered immediately when tunnel construction advances by 20 to 50 meters, or when abnormal situations such as sudden changes in geological structure or gas concentration are encountered.

[0086] Furthermore, in step three, a weighted summation method is used to calculate the comprehensive risk value R of the evaluation object; the specific process is as follows:

[0087] R = (G score × G weight) + (E score × E weight) + (C score × C weight) + (A score × A weight);

[0088] 1) G score

[0089] G score = (G1 score × G1 weight) + (G2 score × G2 weight) + (G3 score × G3 weight) + (G4 score × G4 weight);

[0090] G1 score = (G 11 Score × G 11 weight) + (G 12 Score × G 12 (weight)

[0091] G2 score = (G 21 Score × G 21 weight) + (G 22 Score × G 22 (weight)

[0092] G3 score = (G 31 Score × G 31 weight) + (G 32 Score × G 32 (weight)

[0093] G4 score = G 41 Score × G 41 Weight

[0094] 2) Score for E

[0095] E score = (E1 score × E1 weight) + (E2 score × E2 weight) + (E3 score × E3 weight) + (E4 score × E4 weight);

[0096] E1 score = (E 11 Score × E11 weight) + (E 12 Score × E 12 (weight) + (E) 13 Score × E 13 (weight)

[0097] E2 score = E 21 Score × E 21 Weight

[0098] E3 score = E 31 Score × E 31 Weight

[0099] E4 score = E 41 Score × E 41 Weight

[0100] 3) Score C

[0101] C score = (C1 score × C1 weight) + (C2 score × C2 weight) + (C3 score × C3 weight);

[0102] C1 score = (C11 Score × C 11 weight) + (C 12 Score × C 12 (weight)

[0103] C2 score = (C 21 Score × C 21 (weight) + (C) 22 Score × C 22 (Weight)

[0104] C3 score = (C 31 Score × C 31 (weight) + (C) 32 Score × C 32 (Weight)

[0105] 4) Score A

[0106] Score A = (Score A1 × Weight A1) + (Score A2 × Weight A2) + (Score A3 × Weight A3);

[0107] A1 score = A 11 Score × A 11 Weight

[0108] A2 score = (A 21 Score × A 21 (weight) + (A) 22 Score × A 22 (Weight)

[0109] A3 score = (A 31 Score × A 31 (weight) + (A) 32 Score × A 32 Weights).

[0110] A multi-factor dynamic assessment system for hazardous gas risk in complex geological tunnels on plateaus includes:

[0111] Data acquisition module: used to acquire geological survey data, on-site hazardous gas test data, construction parameters, and plateau environmental parameters;

[0112] Model building and weight calculation module: used to build the GECA indicator system and calculate the combined weights;

[0113] The dynamic risk assessment module is used to calculate the comprehensive risk value and classify the risk level based on fuzzy comprehensive evaluation.

[0114] Early warning and decision support module: Outputs corresponding prevention and control measures suggestions based on the risk level, and issues an early warning when the risk exceeds the threshold.

[0115] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of a multi-factor dynamic evaluation method for the risk of harmful gases in complex geological tunnels on plateaus.

[0116] A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of a method for dynamic evaluation of the risk of harmful gases in tunnels with complex geological conditions on plateaus are disclosed.

[0117] The beneficial effects of this invention are:

[0118] 1) This invention establishes the GECA framework, which integrates geological structure, gas characteristics, construction activities and special environmental effects of plateau into a unified system for comprehensive evaluation, overcoming the limitations of traditional methods with single indicators.

[0119] 2) This invention adopts the AHP-entropy weighting method to combine weights, which not only absorbs expert experience but also fully respects the objective data laws, making the weight allocation more reasonable and reliable.

[0120] 3) This invention quantifies and integrates the influence of low air pressure on the explosion limit in the form of a modified formula, which significantly improves the accuracy of risk assessment in the special environment of the plateau.

[0121] 4) This invention establishes a mechanism that dynamically updates with the construction progress, which can capture risk changes in real time, realizing the leap from static assessment to dynamic early warning, and greatly improving the initiative and effectiveness of risk control.

[0122] 5) This invention establishes a risk classification system of 4 levels and 12 sub-levels, and formulates specific countermeasures for each level, thereby realizing refined risk management and precise delivery of prevention and control measures. Attached Figure Description

[0123] Figure 1 This is a flowchart illustrating the overall process framework of the method of the present invention;

[0124] Figure 2 This is a diagram illustrating the GECA evaluation index system structure of the present invention.

[0125] Figure 3 This is a flowchart for dynamic risk assessment and early warning. Detailed Implementation

[0126] The present invention will now be described in detail with reference to specific embodiments.

[0127] This invention provides a method, system, equipment, and storage medium for dynamic evaluation of multi-factor hazardous gas risks in tunnels with complex geological conditions on plateaus, enabling accurate and dynamic quantitative evaluation of risks and providing decision support for safe construction of tunnels on plateaus.

[0128] like Figure 1 , 2 As shown, the present invention provides a multi-factor dynamic evaluation method for the risk of harmful gases in tunnels with complex geological conditions on plateaus, comprising the following steps:

[0129] Step 1: Construct a GECA evaluation index system that integrates geological structure gas control (G), gas occurrence characteristics (E), construction disturbance effect (C), and plateau environmental effect (A).

[0130] The GECA evaluation index system includes four primary indicators: gas control by geological structure (G); gas occurrence characteristics (E); construction disturbance effect (C); and plateau environmental effect (A).

[0131] The quantification of the high-altitude environmental effect A includes using a modified formula for the explosion limits of combustible gases due to the low atmospheric pressure at high altitudes:

[0132] Explosion lower limit correction formula:

[0133] Explosion limit correction formula:

[0134]

[0135] Where LEL is the lower explosive limit concentration of combustible gas (%); UEL is the upper explosive limit concentration of combustible gas (%); and P is atmospheric pressure (MPa).

[0136] 1) Geological structure controls gas production (G)

[0137] It includes four secondary indicators: structural complexity G1; stratigraphic lithology combination G2; geostress field characteristics G3; and hydrogeological conditions G4.

[0138] ①Construction complexity G1

[0139] Includes two tertiary indicators: fracture density G 11 and wrinkle strength G 12 ;

[0140] Fracture density: >3 fractures / km², score 10; 1-3 fractures / km², score 6; 0-1 fractures / km², score 1.

[0141] Fold strength: Fold curvature radius < 5km, score 8 points; fold curvature radius 5-10km, score 4 points; fold curvature radius > 10km, score 1 point;

[0142] ② Stratigraphic lithology combination G2

[0143] Includes two tertiary indicators: coal-bearing strata thickness G 21 Top plate sealing G 22 ;

[0144] Coal-bearing strata thickness: >3.5m, score 10; 1.3-3.5m, score 6; <1.3m, score 1.

[0145] Roof sealing performance: Roof mudstone thickness > 10m, score 10 points; roof mudstone thickness 5-10m, score 6 points; roof mudstone thickness < 5m, score 1 point;

[0146] ③ Characteristics of the geostress field G3

[0147] Includes two tertiary indicators: the magnitude of geostress G. 31 Stress concentration degree G 32 ;

[0148] Ground stress magnitude: >25MPa, score 8 points; 15-25MPa, score 5 points; <15MPa, score 2 points;

[0149] Stress concentration level: Stress concentration factor > 1.5, score 8 points; Stress concentration factor 1.2-1.5, score 5 points; Stress concentration factor < 1.2, score 2 points;

[0150] ④ Hydrogeological conditions G4

[0151] Includes one tertiary indicator: groundwater activity G 41 ;

[0152] Groundwater permeability coefficient >10 -5 m / s, score 8 points; groundwater permeability coefficient 10 -6 -10 -5 m / s, score 5 points; groundwater permeability coefficient <10 -6 m / s, rating 2 points;

[0153] 2) Gas occurrence characteristics E

[0154] It includes four secondary indicators: gas concentration level E1; gas pressure E2; gas origin type E3; and emission form E4.

[0155] ① Gas concentration level E1

[0156] Includes three tertiary indicators: CH4 concentration E 11 H2S concentration E 12 and CO2 concentration E 13 ;

[0157] CH4 concentration: >10000ppm, score 10; 1000-10000ppm, score 6; <1000ppm, score 1.

[0158] H2S concentration: >20ppm, score 10; 10-20ppm, score 6; <10ppm, score 1.

[0159] CO2 concentration: >5000ppm, score 10; 1000-5000ppm, score 6; <1000ppm, score 1.

[0160] ②Gas pressure E2

[0161] Includes one tertiary indicator: gas pressure E 21 ;

[0162] Gas pressure >0.74MPa, score 10; 0.5-0.74MPa, score 6; <0.5MPa, score 1.

[0163] ③ Gas origin type E3

[0164] Includes one tertiary indicator: causal discrimination E 31 ;

[0165] Inorganic origin, score 8 points; mixed origin, score 5 points; organic origin, score 2 points;

[0166] Inorganic origin: methane carbon isotope ratio δ¹³C-CH₄ < -45‰; Mixed origin: methane carbon isotope ratio -45‰ ≤ δ¹³C-CH₄ ≤ -25‰; Organic origin: methane carbon isotope ratio δ¹³C-CH₄ > -25‰;

[0167] ④ Outflow Form E4

[0168] Includes one tertiary indicator: Outflow characteristic E 41

[0169] A gas outburst velocity fluctuation coefficient δ > 0.6 earns a score of 10; a gas outburst velocity fluctuation coefficient δ between 0.3 and 0.6 earns a score of 5; and a gas outburst velocity fluctuation coefficient δ < 0.3 earns a score of 1.

[0170] 3) Construction disturbance effect C

[0171] It includes three secondary indicators: excavation process (C1); ventilation condition (C2); and support measures (C3).

[0172] ① Excavation process C1

[0173] Includes two tertiary indicators: tunneling speed C 11 Excavation section C 12 ;

[0174] Tunneling speed: >5m / d, score 8 points; 3-5m / d, score 5 points; <3m / d, score 2 points;

[0175] Excavation cross-section: >150m², score 8 points; 100-150m², score 5 points; <100m², score 2 points;

[0176] ②Ventilation status C2

[0177] Includes two tertiary indicators: air volume adequacy C 21 Distance C between the duct and the working face 22 ;

[0178] Airflow adequacy: <60% of demand, score 10; 60-80%, score 6; >80%, score 1.

[0179] Distance between air duct and working face: >15m, score 8 points; 10-15m, score 5 points; <10m, score 2 points;

[0180] ③Support measures C3

[0181] Includes two tertiary indicators: support timeliness C 31 Airtightness measures C 32 ;

[0182] Support timeliness: Delay > 2 cycles, score 8 points; Delay 1-2 cycles, score 5 points; Timely support, score 2 points;

[0183] Air tightness measures: Lining permeability coefficient K > 10⁻ 9 m / s, score 8 points; lining permeability coefficient 10 -10 m / s≤K≤10⁻ 9 m / s, score 5 points; lining permeability coefficient K<10 -10 m / s, rating 2 points;

[0184] 4) Plateau environmental effects A

[0185] It includes three secondary indicators: altitude (A1); atmospheric conditions (A2); and climate characteristics (A3).

[0186] ① Altitude A1

[0187] Includes one tertiary indicator: Altitude Value A 11

[0188] Altitude: >4000m, score 10; 3000-4000m, score 6; <3000m, score 1.

[0189] ②Atmospheric conditions A2

[0190] Includes two tertiary indicators: atmospheric pressure A 21 Oxygen content A 22 ;

[0191] Atmospheric pressure: <61kPa, score 8; 61-70kPa, score 5; >70kPa, score 2;

[0192] Oxygen content: <18%, score 8 points; 18-20%, score 5 points; >20%, score 2 points;

[0193] ③Climate characteristics A3

[0194] Includes two tertiary indicators: temperature change A 31 Wind speed affects A 32 ;

[0195] Daily temperature range: >20℃, score 8 points; 10-20℃, score 5 points; <10℃, score 2 points;

[0196] Wind speed impact: Annual average wind speed at the tunnel entrance >6m / s, score 8 points; annual average wind speed at the tunnel entrance 3~6m / s, score 5 points; annual average wind speed at the tunnel entrance <3m / s, score 2 points.

[0197] Step Two: Determine the weights of indicators at each level using a combined weighting method; specifically:

[0198] Step 2.1: Determine the subjective weights W using the Analytic Hierarchy Process (AHP). AHP,j No fewer than 15 experts in geology, tunnels and safety were invited to conduct pairwise comparative judgments.

[0199] Step 2.2: Determine the objective weight W based on the field measurement data using the Entropy Weight Method (EWM). EVM,j Information entropy E j The calculation formula is: E j Let m be the information entropy of the j-th indicator; m be the number of samples; P ij Let represent the feature weight of the i-th sample under the j-th indicator;

[0200] Step 2.3: Final combined weight W j Through formula Calculate, where W j α represents the final combined weight of the j-th indicator; α is the preference coefficient, which is 0.6.

[0201] Step 3: Based on geological surveys, field tests, and construction records, and according to Table 1, obtain the original parameters and assigned values ​​for this section, and calculate the comprehensive risk value R of the evaluation object; in Step 3, the weighted summation method is used to calculate the comprehensive risk value R of the evaluation object; the specific process is as follows:

[0202] R = (G score × G weight) + (E score × E weight) + (C score × C weight) + (A score × A weight);

[0203] 1) G score

[0204] G score = (G1 score × G1 weight) + (G2 score × G2 weight) + (G3 score × G3 weight) + (G4 score × G4 weight);

[0205] G1 score = (G 11 Score × G 11 weight) + (G 12 Score × G 12 (weight)

[0206] G2 score = (G 21 Score × G 21 weight) + (G 22 Score × G 22 (weight)

[0207] G3 score = (G 31 Score × G 31 weight) + (G 32 Score × G 32 (weight)

[0208] G4 score = G 41 Score × G 41 Weight

[0209] 2) Score for E

[0210] E score = (E1 score × E1 weight) + (E2 score × E2 weight) + (E3 score × E3 weight) + (E4 score × E4 weight);

[0211] E1 score = (E 11 Score × E11 weight) + (E 12 Score × E 12 (weight) + (E) 13 Score × E 13 (weight)

[0212] E2 score = E 21 Score × E 21 Weight

[0213] E3 score = E 31 Score × E 31 Weight

[0214] E4 score = E 41 Score × E 41 Weight

[0215] 3) Score C

[0216] C score = (C1 score × C1 weight) + (C2 score × C2 weight) + (C3 score × C3 weight);

[0217] C1 score = (C 11 Score × C 11 weight) + (C 12 Score × C 12 (weight)

[0218] C2 score = (C 21 Score × C 21 (weight) + (C) 22 Score × C 22 (Weight)

[0219] C3 score = (C 31 Score × C 31 (weight) + (C) 32 Score × C 32 (Weight)

[0220] 4) Score A

[0221] Score A = (Score A1 × Weight A1) + (Score A2 × Weight A2) + (Score A3 × Weight A3);

[0222] A1 score = A 11 Score × A 11 Weight

[0223] A2 score = (A 21 Score × A 21 (weight) + (A) 22 Score × A 22 (Weight)

[0224] A3 score = (A 31 Score × A 31 (weight) + (A) 32 Score × A 32 Weights).

[0225] Step 4: Determine the risk level based on the comprehensive risk value R; the method for determining the risk level is as follows:

[0226] 1) Level I: Extremely high risk, R≥85; Level I is divided into: I-A, R≥90; I-B, 85≤R<90;

[0227] 2) Level II: High risk, 70≤R<85; Level II is divided into: II-A, 80≤R<85; II-B, 75≤R<80; II-C, 70≤R<75;

[0228] 3) Level III: Medium risk, 55≤R<70; Level III is divided into: III-A, 65≤R<70; III-B, 60≤R<65; III-C, 55≤R<60;

[0229] 4) Level IV: Low risk, R<55; Level IV is divided into: IV-A, 45≤R<55; IV-B, 30≤R<45; IV-C, R<30.

[0230] Step 5: As construction progresses, dynamically update the indicator parameters using advanced geological forecasting and real-time monitoring data, and re-execute Steps 3 and 4 to achieve dynamic tracking and early warning of risks. The dynamic update is triggered immediately when tunnel construction advances by 20 to 50 meters, or when encountering abnormal situations such as sudden changes in geological structure or gas concentration.

[0231] The specific implementation method is as follows:

[0232] Taking the section from DK1005+590 to DK1005+460 of a high-altitude railway tunnel (altitude 3650m, air pressure approximately 64.5kPa) as an example, the steps include:

[0233] Step 1: Construct a GECA evaluation index system that integrates geological structure gas control (G), gas occurrence characteristics (E), construction disturbance effect (C), and plateau environmental effect (A). Use a combined weighting method to determine the weights of each level of index, as follows;

[0234]

[0235]

[0236] Among them, the gas emission velocity fluctuation coefficient δ is the ratio of the standard deviation to the average value of the emission velocity (δ=σ / μ), which reflects the stability of the gas emission.

[0237] Step Two: Based on geological surveys, field tests, and construction records, obtain the original parameters and assign values ​​for this section as follows:

[0238]

[0239]

[0240]

[0241]

[0242] Step 3: Substitute into the GECA model. The R-value is calculated using a weighted summation method, aggregating upwards from the third-level indicators. The process is as follows:

[0243] ① Weighted score calculation for tertiary indicators: The score of each tertiary indicator is multiplied by its weight under the secondary indicator.

[0244] For example, for G1 (construction complexity), it includes G 11 and G 12 The calculation process is as follows:

[0245] G1 score = (G 11 Score × G 11 weight) + (G 12 Score × G 12 Weight) = (10 × 0.60) + (1 × 0.40) = 6.0 + 0.4 = 6.4 points.

[0246] Similarly, the scores for all secondary indicators are calculated.

[0247] ② Calculation of weighted scores for secondary indicators: Multiply the scores of secondary indicators by their weights under the primary indicators, and sum them to obtain the scores of the primary indicators.

[0248] For example, G (geological structure-controlled gas) includes G1, G2, G3, and G4.

[0249] G score = (G1 score × G1 weight) + (G2 score × G2 weight) + (G3 score × G3 weight) + (G4 score × G4 weight) = (6.4 × 0.40) + (10 × 0.30) + (2 × 0.20) + (2 × 0.10) = 2.56 + 3.0 + 0.4 + 0.2 = 6.16 points.

[0250] Similarly, the scores for all primary indicators are calculated. E score: 1.5 points after weighting based on low-risk gas concentration and pressure; C score: 3.0 points after weighting based on medium-risk construction disturbance; A score: 5.5 points after weighting based on medium-risk altitude and air pressure, and high-risk oxygen content.

[0251] ③ Calculation of comprehensive risk value R: Multiply the scores of the primary indicators by their total weights (G: 0.35, E: 0.30, C: 0.20, A: 0.15) and sum them up.

[0252] R = (G score × 0.35) + (E score × 0.30) + (C score × 0.20) + (A score × 0.15) = (6.16 × 0.35) + (1.5 × 0.30) + (3.0 × 0.20) + (5.5 × 0.15) = 2.156 + 0.45 + 0.6 + 0.825 = 43.5 points;

[0253] Step 4: According to Table 1 (Risk Level Classification Standard), R=43.5 belongs to Sub-Level IV-B of Level IV (Low Risk).

[0254] Step 5: The system outputs a low-risk alert and pushes the corresponding countermeasures: routine management. No additional gas control measures are required. Actual verification showed that multiple gas exceedance warnings occurred during this construction section, highly consistent with the model evaluation results, proving the effectiveness and reliability of the invention.

[0255] Table 1 Risk Level Classification Criteria and Countermeasures

[0256]

[0257] This invention also provides a multi-factor dynamic evaluation system for the risk of harmful gases in complex geological tunnels on plateaus, including:

[0258] Data acquisition module: used to acquire geological survey data, on-site hazardous gas test data, construction parameters, and plateau environmental parameters;

[0259] Model building and weight calculation module: used to build the GECA indicator system and calculate the combined weights;

[0260] The dynamic risk assessment module is used to calculate the comprehensive risk value and classify the risk level based on fuzzy comprehensive evaluation.

[0261] Early warning and decision support module: Outputs corresponding prevention and control measures suggestions based on the risk level, and issues an early warning when the risk exceeds the threshold.

[0262] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor; when the processor executes the computer program, it implements the steps of the present invention's method for dynamic evaluation of the risk of harmful gases in complex geological tunnels on plateaus.

[0263] The present invention also provides a computer-readable storage medium having a computer program stored thereon; when the computer program is executed by a processor, it implements the steps of the method for dynamic evaluation of the risk of harmful gases in complex geological tunnels on plateaus according to the present invention.

[0264] The content of this invention is not limited to the embodiments listed. Any equivalent modifications made by those skilled in the art to the technical solutions of this invention by reading this specification are covered by the claims of this invention.

Claims

1. A multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus, characterized in that: Includes the following steps: Step 1: Construct a GECA evaluation index system that integrates geological structure gas control (G), gas occurrence characteristics (E), construction disturbance effect (C), and plateau environmental effect (A). The GECA evaluation index system includes four primary indicators: geological structure gas control (G); gas occurrence characteristics (E); construction disturbance effect (C); and plateau environmental effect (A). Step 2: Determine the weights of indicators at each level using a combined weighting method; Step 3: Based on geological surveys, field tests, and construction records, obtain the original parameters and values ​​for this section, and calculate the comprehensive risk value R of the evaluation object; Step 4: Determine the risk level based on the comprehensive risk value R; Step 5: As construction progresses, dynamically update the indicator parameters using advanced geological forecasts and real-time monitoring data, and re-execute Steps 3 and 4 to achieve dynamic tracking and early warning of risks.

2. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 1, characterized in that: Step one specifically involves: 1) Geological structure controls gas production (G) It includes four secondary indicators: structural complexity G1; stratigraphic lithology combination G2; geostress field characteristics G3; and hydrogeological conditions G4. ①Construction complexity G1 Includes two tertiary indicators: fracture density G 11 and wrinkle strength G 12 ; Fracture density: >3 fractures / km², score 10; 1-3 fractures / km², score 6; 0-1 fractures / km², score 1. Fold strength: Fold curvature radius < 5km, score 8 points; fold curvature radius 5-10km, score 4 points; fold curvature radius > 10km, score 1 point; ② Stratigraphic lithology combination G2 Includes two tertiary indicators: coal-bearing strata thickness G 21 Top plate sealing G 22 ; Coal-bearing strata thickness: >3.5m, score 10 points; 1.3-3.5m, score 6 points; <1.3m, score 1 point; Roof sealing performance: Roof mudstone thickness > 10m, score 10 points; roof mudstone thickness 5-10m, score 6 points; roof mudstone thickness < 5m, score 1 point; ③ Characteristics of the geostress field G3 Includes two tertiary indicators: the magnitude of geostress G. 31 Stress concentration degree G 32 ; Ground stress magnitude: >25MPa, score 8 points; 15-25MPa, score 5 points; <15MPa, score 2 points; Stress concentration level: Stress concentration factor > 1.5, score 8 points; Stress concentration factor 1.2-1.5, score 5 points; Stress concentration factor < 1.2, score 2 points; ④ Hydrogeological conditions G4 Includes one tertiary indicator: groundwater activity G 41 ; Groundwater permeability coefficient >10 -5 m / s, score 8 points; groundwater permeability coefficient 10 -6 -10 -5 m / s, score 5 points; groundwater permeability coefficient <10 -6 m / s, rating 2 points; 2) Gas occurrence characteristics E It includes four secondary indicators: gas concentration level E1; gas pressure E2; gas origin type E3; and emission form E4. ① Gas concentration level E1 Includes three tertiary indicators: CH4 concentration E 11 H2S concentration E 12 and CO2 concentration E 13 ; CH4 concentration: >10000ppm, score 10; 1000-10000ppm, score 6; <1000ppm, score 1. H2S concentration: >20ppm, score 10; 10-20ppm, score 6; <10ppm, score 1. CO2 concentration: >5000ppm, score 10; 1000-5000ppm, score 6; <1000ppm, score 1. ②Gas pressure E2 Includes one tertiary indicator: gas pressure E 21 ; Gas pressure > 0.74 MPa, score 10; 0.5-0.74 MPa, score 6 points; <0.5 MPa, score 1 point; ③ Gas origin type E3 Includes one tertiary indicator: causal discrimination E 31 ; Inorganic origin, score 8 points; mixed origin, score 5 points; organic origin, score 2 points; ④ Outflow Form E4 Includes one tertiary indicator: Outflow characteristic E 41 A gas outburst velocity fluctuation coefficient δ > 0.6 earns a score of 10; a gas outburst velocity fluctuation coefficient δ between 0.3 and 0.6 earns a score of 5; and a gas outburst velocity fluctuation coefficient δ < 0.3 earns a score of 1. 3) Construction disturbance effect C It includes three secondary indicators: excavation process (C1); ventilation condition (C2); and support measures (C3). ① Excavation process C1 Includes two tertiary indicators: tunneling speed C 11 Excavation section C 12 ; Tunneling speed: >5m / d, score 8 points; 3-5m / d, score 5 points; <3m / d, score 2 points; Excavation cross-section: >150m², score 8 points; 100-150m², score 5 points; <100m², score 2 points; ② Ventilation status C2 Includes two tertiary indicators: air volume adequacy C 21 Distance C between the duct and the working face 22 ; Airflow adequacy: <60% of demand, score 10; 60-80% of demand, score 6; >80% of demand, score 1. Distance between air duct and working face: >15m, score 8 points; 10-15m, score 5 points; <10m, score 2 points; ③Support measures C3 Includes two tertiary indicators: support timeliness C 31 Airtightness measures C 32 ; Support timeliness: Delay > 2 cycles, score 8 points; Delay 1-2 cycles, score 5 points; Timely support, score 2 points; Air tightness measures: Lining permeability coefficient K > 10⁻ 9 m / s, score 8 points; lining permeability coefficient 10 -10 m / s≤K≤10⁻ 9 m / s, score 5 points; lining permeability coefficient K<10 -10 m / s, rating 2 points; 4) Plateau environmental effects A It includes three secondary indicators: altitude (A1); atmospheric conditions (A2); and climate characteristics (A3). ① Altitude A1 Includes one tertiary indicator: Altitude Value A 11 Altitude: >4000m, score 10; 3000-4000m, score 6; <3000m, score 1. ②Atmospheric conditions A2 Includes two tertiary indicators: atmospheric pressure A 21 Oxygen content A 22 ; Atmospheric pressure: <61kPa, score 8; 61-70kPa, score 5; >70kPa, score 2; Oxygen content: <18%, score 8 points; 18-20%, score 5 points; >20%, score 2 points; ③Climate characteristics A3 Includes two tertiary indicators: temperature change A 31 Wind speed affects A 32 ; Daily temperature range: >20℃, score 8 points; 10-20℃, score 5 points; <10℃, score 2 points; Wind speed impact: Annual average wind speed at the tunnel entrance >6m / s, score 8 points; annual average wind speed at the tunnel entrance 3~6m / s, score 5 points; annual average wind speed at the tunnel entrance <3m / s, score 2 points.

3. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 2, characterized in that: Step two specifically involves: Step 2.1: Determine the subjective weights W using the Analytic Hierarchy Process (AHP). AHP,j ; Step 2.2: Determine the objective weight W based on the field measurement data using the entropy weight method. EVM,j ; Step 2.3: Final combined weight W j Through formula Calculate, where W j α represents the final combined weight of the j-th indicator; α is the preference coefficient.

4. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 3, characterized in that: In step four, the risk level is determined as follows: 1) Level I: Extremely high risk, R≥85; Level I is divided into: I-A, R≥90; I-B, 85≤R<90; 2) Level II: High risk, 70≤R<85; Level II is divided into: II-A, 80≤R<85; II-B, 75≤R<80; II-C, 70≤R<75; 3) Level III: Medium risk, 55≤R<70; Level III is divided into: III-A, 65≤R<70; III-B, 60≤R<65; III-C, 55≤R<60; 4) Level IV: Low risk, R<55; Level IV is divided into: IV-A, 45≤R<55; IV-B, 30≤R<45; IV-C, R<30.

5. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 4, characterized in that: The quantification of the plateau environmental effect A includes using a modified formula for the explosion limit of combustible gases based on the low air pressure at high altitudes: Explosion lower limit correction formula: Explosion limit correction formula: Where LEL is the lower explosive limit concentration of combustible gas; UEL is the upper explosive limit concentration of combustible gas; and P is atmospheric pressure.

6. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 5, characterized in that: In step five, the dynamic update is triggered immediately when the tunnel construction advances by 20 to 50 meters, or when abnormal situations such as sudden changes in geological structure or gas concentration are encountered.

7. The multi-factor dynamic evaluation method for hazardous gas risk in complex geological tunnels on plateaus as described in claim 6, characterized in that: In step three, the weighted summation method is used to calculate the comprehensive risk value R of the evaluation object; the specific process is as follows: R = (G score × G weight) + (E score × E weight) + (C score × C weight) + (A score × A weight); 1) G score G score = (G1 score × G1 weight) + (G2 score × G2 weight) + (G3 score × G3 weight) + (G4 score × G4 weight); G1 score = (G 11 Score × G 11 weight) + (G 12 Score × G 12 (weight) G2 score = (G 21 Score × G 21 weight) + (G 22 Score × G 22 (weight) G3 score = (G 31 Score × G 31 weight) + (G 32 Score × G 32 (weight) G4 score = G 41 Score × G 41 Weight 2) Score for E E score = (E1 score × E1 weight) + (E2 score × E2 weight) + (E3 score × E3 weight) + (E4 score × E4 weight); E1 score = (E 11 Score × E11 weight) + (E 12 Score × E 12 (weight) + (E) 13 Score × E 13 (weight) E2 score = E 21 Score × E 21 Weight E3 score = E 31 Score × E 31 Weight E4 score = E 41 Score × E 41 Weight 3) Score C C score = (C1 score × C1 weight) + (C2 score × C2 weight) + (C3 score × C3 weight); C1 score = (C 11 Score × C 11 weight) + (C 12 Score × C 12 (weight) C2 score = (C 21 Score × C 21 (weight) + (C) 22 Score × C 22 (Weight) C3 score = (C 31 Score × C 31 (weight) + (C) 32 Score × C 32 (Weight) 4) Score A A score = (A1 score × A1 weight) + (A2 score × A2 weight) + (A3 score × A3 weight); A1 score = A 11 Score × A 11 Weight A2 score = (A 21 Score × A 21 (weight) + (A) 22 Score × A 22 (Weight) A3 score = (A 31 Score × A 31 (weight) + (A) 32 Score × A 32 Weights).

8. A multi-factor dynamic evaluation system for hazardous gas risks in complex geological tunnels on plateaus, characterized in that: include: Data acquisition module: used to acquire geological survey data, on-site hazardous gas test data, construction parameters, and plateau environmental parameters; Model building and weight calculation module: used to build the GECA indicator system and calculate the combined weights; The dynamic risk assessment module is used to calculate the comprehensive risk value and classify the risk level based on fuzzy comprehensive evaluation. Early warning and decision support module: Outputs corresponding prevention and control measures suggestions based on the risk level, and issues an early warning when the risk exceeds the threshold.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, it implements the steps of the method as described in any one of claims 1 to 7.

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