A method and equipment for determining gas outbursts during the construction of high-altitude tunnels
By constructing a triple fitting relationship between gas pressure and desorption index, and atmospheric pressure and altitude, a dynamic threshold calculation model was established, which solved the problem of accuracy in judging gas outbursts during the construction period of plateau tunnels and improved the reliability of early warning.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINA RAILWAY ERYUAN ENGINEERING GROUP CO LTD
- Filing Date
- 2026-03-31
- Publication Date
- 2026-06-30
AI Technical Summary
Existing methods for determining gas outbursts in high-altitude areas are based on experience from low-altitude regions and cannot accurately reflect the actual risks in high-altitude tunnels, resulting in insufficient reliability of early warnings and a risk of missed detections.
A triple fitting relationship was constructed between gas pressure and desorption index, atmospheric pressure and gas pressure critical value, and altitude and atmospheric pressure. A calculation model for the gas desorption index threshold of coal drill cuttings that dynamically changes with altitude was established. The specific judgment threshold of the target work area was calculated by fitting the relationship.
Accurately identify gas outburst areas, avoid the risk of missed detection, and improve the reliability of gas outburst early warning during the construction of high-altitude tunnels.
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Figure CN122310176A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of gas index assessment technology, specifically to a method and equipment for determining gas outbursts during the construction of high-altitude tunnels. Background Technology
[0002] Coal and gas outbursts are one of the main hazards threatening construction safety during high-altitude tunnel construction. Accurately predicting the risk of gas outbursts is crucial for ensuring personnel safety and controlling project progress. Currently, the industry typically assesses the risk of gas outbursts based on fixed critical values specified in existing technical specifications. For example, this involves measuring the gas desorption index of coal drill cuttings and comparing it with a unified standard value to determine the presence of an outburst risk.
[0003] However, existing judgment methods are mainly based on engineering experience and statistical data from low-altitude areas, and their applicable conditions differ significantly from those in plateau environments. Plateau regions have higher altitudes and significantly lower atmospheric pressure than plains, while gas occurrence and desorption characteristics are closely related to the pressure environment. Under the low-pressure conditions of plateau regions, the gas desorption behavior and outburst critical conditions of coal seams change, making it difficult to accurately reflect the actual gas outburst risk in plateau tunnels using fixed judgment standards from low-altitude areas. Directly applying conventional judgment indicators may lead to an underestimation or misjudgment of the gas outburst risk in plateau tunnels, thus affecting the accuracy and reliability of early warnings. Missed judgments will create safety hazards for tunnel construction and increase the risk of coal and gas outburst accidents. Therefore, improving the reliability of gas outburst early warning during the construction of plateau tunnels has become an urgent technical problem to be solved in the field of engineering safety. Summary of the Invention
[0004] Based on this, this application provides a method and equipment for determining gas outbursts during the construction of high-altitude tunnels, in order to improve the reliability of early warning of gas outbursts during the construction of high-altitude tunnels.
[0005] Firstly, this application provides a method for determining gas outbursts during the construction of high-altitude tunnels, including:
[0006] The first fitting relationship characterizing the gas pressure and the threshold of the gas desorption index of coal drill cuttings, the second fitting relationship characterizing the atmospheric pressure and the gas pressure outburst critical value, and the third fitting relationship characterizing the altitude and atmospheric pressure were determined respectively. Based on the first fitting relationship, the second fitting relationship and the third fitting relationship, a calculation model is established for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel; The target coal drill cuttings gas desorption index threshold is calculated according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, the target work area is determined to be a gas outburst work area. The target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area.
[0007] Optionally, the gas desorption index for coal drill cuttings includes both dry coal drill cuttings gas desorption index and wet coal drill cuttings gas desorption index; when using the dry coal drill cuttings gas desorption index, the first fitting relationship is:
[0008] in, The threshold value for gas desorption index in dry coal drill cuttings. For gas pressure, , , The fitting parameters are as follows; when using the wet coal drill cuttings gas desorption index, the first fitting relationship is:
[0009] in, The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings.
[0010] Optionally, the second fitting relationship is:
[0011] in, This is the critical value for gas pressure outburst. This is the critical value coefficient for gas pressure. This is the atmospheric pressure value.
[0012] Optionally, the third fitting relationship is:
[0013] in, This is the atmospheric pressure value. and For fitting parameters, This refers to altitude.
[0014] Optionally, when using the dry coal drill cuttings gas desorption index, the calculation model is as follows:
[0015] When using the wet coal drill cuttings gas desorption index, the calculation model is as follows:
[0016] in, The threshold value for gas desorption index in dry coal drill cuttings. The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings. For gas pressure, The threshold value for gas desorption index in dry coal drill cuttings. , , For fitting parameters, This is the critical value coefficient for gas pressure. This is the atmospheric pressure value. and For fitting parameters, This refers to altitude.
[0017] Secondly, this application provides a gas outburst detection device for high-altitude tunnel construction, comprising: The first calculation module is used to determine the first fitting relationship characterizing the threshold of gas desorption index of coal drill cuttings, the second fitting relationship characterizing atmospheric pressure and the critical value of gas pressure outburst, and the third fitting relationship characterizing altitude and atmospheric pressure. The second calculation module is used to establish a calculation model for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel based on the first fitting relationship, the second fitting relationship and the third fitting relationship; The judgment module is used to calculate the target coal drill cuttings gas desorption index threshold according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, the target work area is determined to be a gas outburst work area. The target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area.
[0018] Furthermore, the device also includes a data acquisition module, used to acquire gas desorption index values of dry coal drill cuttings and / or wet coal drill cuttings under different gas pressures to establish the first fitting relationship; acquire atmospheric pressure values at different altitudes to establish the third fitting relationship; acquire gas pressure outburst critical values at different atmospheric pressures to establish the second fitting relationship; and acquire measured values of altitude and / or coal drill cuttings gas desorption index of the target work area for the judgment module to call.
[0019] Furthermore, the device also includes an output and storage module for outputting and storing the judgment results of the critical outburst risk of the drill cuttings gas desorption index of the target work area.
[0020] Compared with existing technologies, the beneficial effects of this application are as follows: By constructing a triple fitting relationship between gas pressure and desorption index, atmospheric pressure and critical gas pressure value, and altitude and atmospheric pressure, a calculation model for the threshold of gas desorption index in coal drill cuttings that dynamically changes with altitude is established. This method uses altitude as the core variable and calculates a specific judgment threshold for the actual altitude of the target work area, overcoming the problem of insufficient adaptability of traditional fixed standards in high-altitude environments. When the measured index reaches or exceeds this dynamic threshold, gas outburst work areas can be accurately identified, effectively avoiding the risk of missed judgments and improving the reliability of gas outburst early warning during high-altitude tunnel construction. Attached Figure Description
[0021] Figure 1 A schematic diagram illustrating the steps of the method for determining gas outburst during the construction period of a plateau tunnel, as provided in this application embodiment.
[0022] Figure 2 This is a schematic diagram of the first fitting relationship provided for an embodiment of this application.
[0023] Figure 3 A schematic diagram showing the linear relationship between different altitudes and corresponding atmospheric pressures obtained through fitting, as provided in the embodiments of this application.
[0024] Figure 4 A schematic diagram of a gas outburst detection device for high-altitude tunnel construction provided in this application embodiment.
[0025] Figure 5 A flowchart illustrating the method for determining gas outbursts during the construction period of a plateau tunnel, as provided in this application embodiment. Detailed Implementation
[0026] The present application will now be described in further detail with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the subject matter of the present application to the following embodiments. All technologies implemented based on the content of the present application fall within the scope of protection of the present application.
[0027] In the description of the embodiments of this application, technical terms such as "first" and "second" only distinguish one entity or operation from another, and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. The reference to "embodiment" herein means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.
[0028] Please refer to Figure 1 , Figure 1 A schematic diagram illustrating the steps of the gas outburst determination method during high-altitude tunnel construction provided in this application embodiment. The gas outburst determination method during high-altitude tunnel construction may include the following steps: S1. Determine the first fitting relationship characterizing the threshold of gas desorption index of coal drill cuttings, the second fitting relationship characterizing the critical value of gas pressure outburst, and the third fitting relationship characterizing the altitude and atmospheric pressure.
[0029] S2. Based on the first fitting relationship, the second fitting relationship, and the third fitting relationship, establish a calculation model for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel.
[0030] S3. Calculate the target coal drill cuttings gas desorption index threshold according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, then the target work area is determined to be a gas outburst work area.
[0031] In this embodiment, the target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area. The target work area is the plateau tunnel construction section where the gas outburst risk assessment is to be carried out, which usually corresponds to a certain working face or a specific coal seam occurrence area during the tunnel excavation process.
[0032] The first fitting relationship is established through mathematical regression analysis based on measured data of gas desorption indices from dry coal drill cuttings under different gas pressure conditions, and is typically expressed as a quadratic polynomial. When using the gas desorption indices from dry coal drill cuttings, the first fitting relationship is:
[0033] in, The threshold value for gas desorption index in dry coal drill cuttings. For gas pressure, , , These are the fitting parameters; When using the wet coal drill cuttings gas desorption index, the first fitting relationship is:
[0034] in, The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings.
[0035] The second fitting relationship was obtained by statistically analyzing atmospheric pressure values at different altitudes. Corresponding critical value for gas pressure outburst Therefore, a linear relationship is generally observed. The second fitting relationship is:
[0036] in, This is the critical value for gas pressure outburst. This is the atmospheric pressure value. It is the critical value coefficient of gas pressure, used to reflect the law of change of the critical value of gas pressure outburst with atmospheric pressure in plateau environment.
[0037] The third fitting relationship is obtained based on measured data of different altitudes H and their corresponding atmospheric pressures p, and conforms to the exponential decay law. Therefore, it can be determined as follows:
[0038] in, This is the atmospheric pressure value. and For fitting parameters, This refers to altitude.
[0039] Based on the first, second, and third fitting relationships described above, a calculation model for the gas desorption index threshold of coal drill cuttings corresponding to the altitude of the plateau tunnel can be established. Specifically, by substituting the gas pressure from the second fitting relationship into the first fitting relationship, and then substituting the third fitting relationship into the expression, intermediate variables can be eliminated. and The threshold for gas desorption from coal drill cuttings is obtained as a function of altitude H only. For dry coal, the calculation model is as follows:
[0040] For wet coal, the calculation model is as follows:
[0041] in, The threshold value for gas desorption index in dry coal drill cuttings. The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings. For gas pressure, The threshold value for gas desorption index in dry coal drill cuttings. , , For fitting parameters, This is the critical value coefficient for gas pressure. This is the atmospheric pressure value. and For fitting parameters, The altitude is considered. This calculation model fully considers the impact of altitude changes on atmospheric pressure in plateau regions, which in turn affects the critical value for gas pressure outbursts and the threshold for gas desorption index of coal drill cuttings, making the outburst judgment criteria at different altitudes more targeted and accurate.
[0042] Furthermore, by obtaining the measured values of gas desorption index from coal drill cuttings at the corresponding altitude of the target work area, such as by measuring the values of gas desorption index from dry or wet coal drill cuttings using direct on-site measurement methods and indirect laboratory measurement methods, the measured values are compared with the calculated threshold. If the measured value of the gas desorption index from coal drill cuttings is greater than or equal to the target threshold, the work area is determined to be a gas outburst area with a risk of coal and gas outburst; otherwise, it is determined to be a gas outburst-free work area.
[0043] To further illustrate the scheme provided in this application, please refer to Table 1, which is a schematic diagram showing the correspondence between the gas desorption index values of dry coal drill cuttings obtained by experimental measurement or field collection under different gas pressure conditions.
[0044] Table 1
[0045] Please refer to Figure 2 , Figure 2 This is a schematic diagram of the first fitting relationship provided in an embodiment of this application. Based on the data in Table 1, the first fitting relationship can be obtained as follows:
[0046] The corresponding threshold for wet coal drill cuttings gas desorption index is:
[0047] The gas desorption index coefficient for wet coal drill cuttings can be determined based on the ratio of the critical values for dry and wet coal in industry standards. For example, the dry coal sample specified in several industry standards... The critical value for the index is 200 Pa, while for wet coal samples... The critical value of the index is 160 Pa, therefore it can be determined. .
[0048] Based on the atmospheric pressure values at different altitudes and the corresponding critical values for gas pressure outbursts, a second fitting relationship for the critical values of gas pressure outbursts at different altitudes is obtained:
[0049] Furthermore, the critical value for gas pressure outburst can be determined through multiple industry standards. The pressure is 0.74 MPa, and the standard atmospheric pressure is 101.32 kPa. For ease of calculation, one standard atmosphere is used. Defined as 0.1 MPa; therefore, it can be determined 7.4.
[0050] Table 2 shows the correspondence between different altitudes and corresponding atmospheric pressure values.
[0051] Table 2
[0052] Please refer to Figure 3 , Figure 3 A schematic diagram illustrating the linear relationship between different altitudes and corresponding atmospheric pressures obtained through fitting, provided for embodiments of this application. Based on the data in Table 2, the atmospheric pressure values at different altitudes H... p The third fitting relationship is:
[0053] Based on the first, second, and third fitting relationships mentioned above, the critical values of the dry coal drilling cuttings gas desorption index at different altitudes in plateau tunnels can be obtained. The calculation model is as follows:
[0054] Critical value of gas desorption index for wet coal drill cuttings The calculation model is as follows:
[0055] Next, based on the regional coal seam geological background, geological conditions, longitudinal profile map, and advanced geological prediction technology, the distribution, thickness, and altitude of the coal seam in the tunnel were determined. Based on the distribution and thickness of the coal seam in the plateau tunnel, the measured values of the gas desorption index of dry coal drill cuttings were obtained by direct on-site measurement or indirect laboratory measurement. Or, the measured values of gas desorption index in wet coal drill cuttings. When the measured value of gas desorption index of dry coal drill cuttings Or, the measured value of gas desorption index in wet coal drill cuttings. If the conditions are met, the work area is classified as a gas outburst zone; otherwise, it is classified as a non-gas outburst zone.
[0056] It should be understood that the first fitting relationship, the second fitting relationship, and the third fitting relationship illustrated in the above embodiments are only fitting results obtained from the above actual data. For different datasets, the fitting coefficients will be adjusted according to the actual data, but all of them are within the protection scope of this application.
[0057] In the aforementioned implementation process, a dynamic threshold calculation model for the gas desorption index of coal drill cuttings was established by constructing a triple fitting relationship between gas pressure and desorption index, atmospheric pressure and critical gas pressure value, and altitude and atmospheric pressure. This model uses altitude as the core variable to calculate a specific judgment threshold for the actual altitude of the target work area, overcoming the problem of insufficient adaptability of traditional fixed standards in high-altitude environments. When the measured index reaches or exceeds this dynamic threshold, gas outburst work areas can be accurately identified, effectively avoiding the risk of missed detection and improving the reliability of gas outburst early warning during high-altitude tunnel construction.
[0058] Based on the same concept, this application also provides a gas outburst detection device for high-altitude tunnel construction. Please refer to [link / reference]. Figure 4 , Figure 4 A schematic diagram of a gas outburst detection device for high-altitude tunnel construction provided in this application embodiment. The gas outburst detection device for high-altitude tunnel construction may include: The first calculation module 11 is used to determine the first fitting relationship characterizing the threshold of gas desorption index of coal drill cuttings, the second fitting relationship characterizing the threshold of gas pressure outburst and the third fitting relationship characterizing the altitude and atmospheric pressure. The second calculation module 12 is used to establish a calculation model for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel based on the first fitting relationship, the second fitting relationship and the third fitting relationship; The judgment module 13 is used to calculate the target coal drill cuttings gas desorption index threshold according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, the target work area is determined to be a gas outburst work area. The target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area.
[0059] Furthermore, the gas outburst judgment device 10 during the construction of high-altitude tunnels may also include a data acquisition module, used to acquire the gas desorption index values of dry coal drill cuttings and / or wet coal drill cuttings under different gas pressures to establish the first fitting relationship; acquire the atmospheric pressure values at different altitudes to establish the third fitting relationship; acquire the gas pressure outburst critical values at different atmospheric pressures to establish the second fitting relationship; and acquire the altitude of the target work area and / or the measured values of the gas desorption index of coal drill cuttings for the judgment module 13 to call.
[0060] Furthermore, the gas outburst determination device 10 during the construction of high-altitude tunnels may also include an output and storage module for outputting and storing the judgment results of the critical outburst risk of the drill cuttings gas desorption index of the target work area.
[0061] It should be understood that when the various modules of the system provided in the above embodiments are working, the division of each functional module in the above description is only used as an example. In actual applications, the above functions can be assigned to different functional modules as needed. That is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.
[0062] The functional modules in the above embodiments can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit. Furthermore, the specific names of the functional units and modules are only for easy differentiation and are not intended to limit the scope of protection of the embodiments of this application.
[0063] The following are examples illustrating the practical application of the gas outburst determination method and equipment provided in this application for high-altitude tunnel construction. Please refer to the embodiments below. Figure 1 Based on the above, refer to Figure 5 , Figure 5 A flowchart illustrating the method for determining gas outbursts during the construction period of a plateau tunnel, as provided in this application embodiment.
[0064] In the first embodiment, a plateau tunnel is located in a mountainous area with intense tectonic activity and significant topographic relief. The tunnel traverses coal-bearing strata with complex lithology, well-developed geological structures, and complex gas occurrence conditions. During tunnel construction, a coal seam (numbered M1-1) with a thickness exceeding 30 cm was exposed at the tunnel face. The thickness of the coal seam, as verified by advanced geological prediction and drilling, is 53-78 cm. According to relevant industry standards, a coal and gas outburst hazard prediction is required.
[0065] Based on regional geological data and tunnel longitudinal profile, the elevation H of the M1-1 coal seam was determined to be 3000m. The elevation data was input into the gas outburst detection device provided in this application, and the device's built-in calculation module performed calculations based on a pre-established fitting relationship model. This model was derived based on the first, second, and third fitting relationships. The calculated critical value for gas pressure outburst at an elevation of 3000m was 0.52 MPa, and the critical value for gas desorption index of dry coal drill cuttings was... The value is 165 Pa.
[0066] A gas test borehole was drilled at the M1-1 coal seam, and the measured value of the gas desorption index of dry coal drill cuttings was obtained by direct on-site measurement. The result was 186 Pa. Comparing the measured value with the critical value, the measured value (186 Pa) is greater than the critical value (165 Pa). Based on this, it can be determined that the work area has a risk of coal and gas outburst.
[0067] In the second embodiment, a plateau tunnel is located on the southeastern edge of a mountain range, mainly traversing coal-bearing strata. The coal seams consist of dozens of layers, distributed in a convex mirror-like or layered pattern, and the strata are relatively stable. During construction, a coal seam (numbered M1) exceeding 30cm in thickness was exposed at the tunnel face, with a thickness ranging from 36 to 53cm, requiring prediction of outburst risk.
[0068] Based on geological data and the tunnel longitudinal section, the elevation H of the M1 coal seam was determined to be 4000m. This elevation was input into the gas outburst detection device, and the calculation module, based on the same fitting model, calculated the critical value for gas pressure outburst at an elevation of 4000m to be 0.45 MPa, and the critical value for gas desorption index of dry coal drill cuttings. The value is 152 Pa.
[0069] A gas test borehole was drilled at the M1 coal seam location to measure the actual value Δh of the gas desorption index of dry coal drill cuttings. 20 The measured value was 126 Pa. Since the measured value (126 Pa) is less than the critical value (152 Pa), it can be determined that there is no risk of coal and gas outburst in this work area.
[0070] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.
Claims
1. A method for determining gas outburst during plateau tunnel construction period, characterized in that, include: The first fitting relationship characterizing the gas pressure and the threshold of the gas desorption index of coal drill cuttings, the second fitting relationship characterizing the atmospheric pressure and the gas pressure outburst critical value, and the third fitting relationship characterizing the altitude and atmospheric pressure were determined respectively. Based on the first fitting relationship, the second fitting relationship, and the third fitting relationship, a calculation model is established for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel. The target coal drill cuttings gas desorption index threshold is calculated according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, the target work area is determined to be a gas outburst work area. The target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area.
2. The high-altitude tunnel construction period gas outburst determination method according to claim 1, characterized in that, The gas desorption index of coal drill cuttings includes the gas desorption index of dry coal drill cuttings and the gas desorption index of wet coal drill cuttings; When using the dry coal drill cuttings gas desorption index, the first fitting relationship is: in, The threshold value for gas desorption index in dry coal drill cuttings. For gas pressure, , , These are the fitting parameters; When using the wet coal drill cuttings gas desorption index, the first fitting relationship is: in, The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings.
3. The method for determining gas outburst during the construction of high-altitude tunnels according to claim 1, characterized in that, The second fitting relationship is: in, This is the critical value for gas pressure outburst. This is the critical value coefficient for gas pressure. This is the atmospheric pressure value.
4. The method for determining gas outburst during the construction of high-altitude tunnels according to claim 1, characterized in that, The third fitting relationship is: in, This is the atmospheric pressure value. and For the fitting parameters, This refers to altitude.
5. The method for determining gas outburst during the construction of high-altitude tunnels according to claim 2, characterized in that, When using the dry coal drill cuttings gas desorption index, the calculation model is as follows: When using the wet coal drill cuttings gas desorption index, the calculation model is as follows: in, The threshold value for gas desorption index in dry coal drill cuttings. The threshold value for gas desorption index in wet coal drill cuttings. The coefficient for gas desorption index of wet coal drill cuttings. For gas pressure, The threshold value for gas desorption index in dry coal drill cuttings. , , For the fitting parameters, This is the critical value coefficient for gas pressure. This is the atmospheric pressure value. and For the fitting parameters, This refers to altitude.
6. A gas outburst detection device for high-altitude tunnel construction, characterized in that, include: The first calculation module is used to determine the first fitting relationship characterizing the threshold of gas desorption index of coal drill cuttings, the second fitting relationship characterizing atmospheric pressure and the critical value of gas pressure outburst, and the third fitting relationship characterizing altitude and atmospheric pressure. The second calculation module is used to establish a calculation model for the threshold of coal drill cuttings gas desorption index corresponding to the altitude of the plateau tunnel based on the first fitting relationship, the second fitting relationship and the third fitting relationship; The judgment module is used to calculate the target coal drill cuttings gas desorption index threshold according to the calculation model. If the measured value of the coal drill cuttings gas desorption index is greater than or equal to the target coal drill cuttings gas desorption index threshold, the target work area is determined to be a gas outburst work area. The target coal drill cuttings gas desorption index threshold is the coal drill cuttings gas desorption index threshold at the corresponding altitude of the target work area.
7. The gas outburst detection device for high-altitude tunnel construction as described in claim 6, characterized in that, The device also includes a data acquisition module for acquiring gas desorption index values of dry coal drill cuttings and / or wet coal drill cuttings under different gas pressures, in order to establish the first fitting relationship. Atmospheric pressure values at different altitudes are collected to establish the third fitting relationship; gas pressure outburst critical values at different atmospheric pressures are collected to establish the second fitting relationship. Additionally, the measured values of the altitude of the target work area and / or the gas desorption index of coal drill cuttings are collected and used by the judgment module.
8. The gas outburst detection device during high-altitude tunnel construction according to claim 6, characterized in that, The device also includes an output and storage module for outputting and storing the judgment results of the critical outburst risk of the drill cuttings gas desorption index of the target work area.