Safe and efficient TBM tunneling coal uncovering method

Abstract

The invention belongs to the technical field of coal mine tunnel tunneling, and particularly relates to a safe and efficient TBM tunneling coal uncovering method which comprises the following steps: when a TBM is tunneled to a certain distance from a coal seam, adopting various advanced detection means to master parameters such as position, thickness and inclination angle of the coal seam; according to the advanced detection result, if the coal seam gas content exceeds the standard, coal seam gas is subjected to pre-drainage through a drainage system; optimizing tunneling parameters of the TBM; a plurality of supporting modes are adopted in the coal uncovering section, and the excavated roadway surrounding rock is supported; a ventilation system is established, it is ensured that sufficient fresh air flow exists in the roadway in the coal uncovering process, and a gas monitoring sensor is installed to monitor the gas concentration in real time. According to the method, the safety and efficiency problems in the TBM tunneling coal uncovering process are effectively solved, the safety and reliability of coal uncovering are improved, gas accidents are reduced, meanwhile, the tunneling efficiency is improved, and the construction time is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine roadway tunneling, and particularly relates to a safe and efficient TBM tunneling and coal uncovering method. Background Art

[0002] During the process of coal mine construction, the TBM tunneling technology has been widely applied due to its advantages such as high efficiency and continuous operation. However, in the coal uncovering link, due to the characteristics of the coal seam itself and the influence of complex geological conditions, problems such as gas outburst and coal body fragmentation occur frequently, seriously threatening the lives of construction workers and at the same time resulting in low tunneling efficiency. Traditional coal uncovering methods have many limitations when facing the rapid tunneling requirements of TBM, and it is impossible to achieve a balance between safety and efficiency.

[0003] Therefore, there is an urgent need for a safe and efficient TBM tunneling and coal uncovering method to realize safe and efficient tunneling and coal uncovering operations in coal mine roadways. Summary of the Invention

[0004] In view of the above-mentioned defects existing in the prior art, the present invention provides a safe and efficient TBM tunneling and coal uncovering method, which includes the following steps:

[0005] S1. Advanced detection: When the TBM tunnels to a certain distance from the coal seam, a variety of advanced detection means are adopted to accurately master parameters such as the position, thickness, dip angle and gas content of the coal seam, providing an accurate basis for subsequent coal uncovering construction.

[0006] S2. Gas pre-drainage: According to the results of advanced detection, if the gas content of the coal seam exceeds the standard, boreholes are drilled in the front area of TBM tunneling, and the coal seam gas is pre-drained through the drainage system to reduce the gas pressure and content and eliminate the risk of gas outburst.

[0007] S3. Optimize tunneling parameters: According to the physical and mechanical properties and gas conditions of the coal seam, optimize the tunneling parameters of the TBM to improve the tunneling efficiency on the premise of ensuring safety.

[0008] S4. Strengthen support: In the coal uncovering section, a variety of support methods are coordinated with each other to timely support the surrounding rock of the excavated roadway to prevent coal body rib spalling and roof fall.

[0009] S5. Ventilation and gas monitoring: Establish a ventilation system to ensure that there is sufficient fresh air flow in the roadway during the coal uncovering process to dilute the gas concentration, and install gas monitoring sensors to monitor the gas concentration in real time. Once the gas concentration exceeds the standard, immediately take measures such as stopping tunneling and evacuating personnel.

[0010] Optionally, step S1 includes the following sub-steps:

[0011] S1.1. Combined detection by multiple means: When the TBM advances to 15-20 meters away from the coal seam, two detection methods, geological radar and advance drilling, are activated. Among them, geological radar uses the principle of electromagnetic wave reflection to quickly obtain the position, thickness and inclination information of the coal seam. The detection frequency is 100-500MHz, and the detection range is 30-50 meters ahead of the excavation. Advance drilling is based on geological radar detection to accurately verify key areas. The number of drill holes is not less than 3, and the drilling depth is determined according to the estimated depth of the coal seam, generally 10-15 meters into the coal seam.

[0012] S1.2. Data analysis and prediction: The data collected by geological radar and advance drilling are transmitted to the data analysis system, and the artificial intelligence algorithm is used to analyze and process the data. By establishing a geological model, the trend of coal seam changes is simulated, and possible geological anomaly areas are predicted to provide accurate geological information for subsequent construction. If abnormal conditions such as sudden changes in gas content and disordered coal seam structure are found, the detection plan is adjusted in time, and detection points are added or other auxiliary detection methods are used.

[0013] Optionally, in step S1.1, during the drilling process, drilling parameters such as drilling speed, torque and pressure are collected in real time, and the location and properties of the coal seam are determined in combination with the characteristics of the rock cuttings. The collected coal samples are tested to determine parameters such as the gas content, gas pressure, and coal body solidity coefficient of the coal samples.

[0014] Optionally, in step S2, according to the advanced detection result, if the gas content of the coal seam exceeds 8m 3 / t or the gas pressure exceeds 0.74MPa. In the area ahead of TBM excavation, the drilling position is determined according to the fan-shaped spacing. The drilling spacing is determined according to the permeability of the coal seam. The spacing in the area with good permeability is 3-5 meters, and the spacing in the area with poor permeability is 1-3 meters. The drilling depth is 0.5-1 meter to penetrate the coal seam and enter the rock layer to ensure that the gas can be effectively extracted.

[0015] Optionally, in step S2, the drainage system includes a drainage pump, a pipeline and a valve, wherein the drainage negative pressure of the drainage pump is not less than 13 kPa, and the flow, concentration and pressure sensors can be installed to detect gas drainage concentration, flow and other parameters in real time. According to the drainage effect, the operating parameters of the drainage pump, such as speed and flow, are dynamically adjusted. The pre-drainage time is not less than 30 days, and the gas content is measured to be reduced to 8m3 for 3 consecutive days. 3 / t or less and the gas pressure drops below 0.74MPa, the pre-extraction can be stopped.

[0016] Optionally, in step S3, sensors installed on the TBM are used to collect stress, vibration and temperature data of the coal body and operation data of the equipment in real time, and these data are combined with the physical and mechanical property data of the coal seam obtained by advance detection, and the excavation parameters are dynamically adjusted through the control system.

[0017] Optionally, in step S3, different tunneling parameters are set for coal seams with different hardnesses: for soft coal seams, the cutterhead rotation speed is controlled at 6 - 8 r / min, the propulsion speed is 10 - 15 mm / min, and the support shoe pressure is increased to 15 - 20 MPa to reduce the impact of the cutterhead on the coal body and prevent excessive fragmentation of the coal body and subsidence of the TBM; for medium-hard coal seams, the cutterhead rotation speed is adjusted to 8 - 10 r / min, the propulsion speed is 15 - 20 mm / min, and the support shoe pressure is maintained at 12 - 15 MPa to ensure stable operation of the equipment while guaranteeing the rock-breaking efficiency; for hard coal seams, the cutterhead rotation speed is increased to 10 - 12 r / min, the propulsion speed is increased to 20 - 25 mm / min, and the support shoe pressure is adjusted to 10 - 12 MPa to improve the rock-breaking efficiency.

[0018] Optionally, in step S4, in the coal uncovering section, a combined support method of bolt, cable bolt, steel arch and shotcrete is adopted; high-strength threaded steel bolts with a diameter of 22 mm and a length of 2.5 - 3 m are selected for the bolts, and the spacing between rows is 0.8 - 1 m; strand cables with a diameter of 17.8 mm and a length of 6 - 8 m are selected for the cable bolts, and the spacing between rows is 1.2 - 1.5 m. The deep stable rock mass of the surrounding rock is connected to the roadway surface through the bolts and cable bolts to provide active support force; install steel arches, the steel arches are made of I-beams or U-shaped steel, and the spacing is 0.6 - 0.8 m to support the roadway surrounding rock in a timely manner; the shotcrete uses concrete with a strength grade of above C25 and is sprayed in 3 times, and the spraying thickness is 15 - 20 cm: the first spraying thickness is 5 - 8 cm to seal the surface of the surrounding rock; the second spraying thickness is 5 - 8 cm to enhance the support strength; the third spraying is to the designed thickness to ensure the integrity of the support structure; during the spraying process, the wet spraying process is adopted to reduce dust generation and improve the quality of the shotcrete.

[0019] Optionally, in step S5, a perfect ventilation system is established, adopting a combination of forced ventilation and exhaust ventilation: install a high-power forced ventilator at the entrance of the roadway to ensure that fresh air can quickly reach the tunneling face, and the air volume is not less than 600 m 3 / min; install an exhaust ventilator at the rear of the roadway to timely discharge the gas and harmful gases generated during tunneling, and the air volume is adjusted according to the length of the roadway and the gas emission volume, generally 300 - 500 m 3 / min; install regulating air doors, air bridges and other facilities in the ventilation system to ensure stable air flow.

[0020] High-precision gas monitoring sensors are installed in key locations such as in front of the TBM cutterhead, inside the shield, and in the return air flow of the tunnel to monitor the gas concentration in real time. When the gas concentration reaches 0.5%, a warning signal is issued. When the gas concentration reaches 1%, the TBM power supply is automatically cut off, excavation is stopped, and the gas data is transmitted to the ground monitoring center through wireless transmission technology, so that management personnel can grasp the underground gas situation in time, activate the emergency plan at the same time, notify the operating personnel to evacuate to a safe area quickly along the predetermined route, and increase the ventilation volume to dilute and discharge the gas until the gas concentration drops below 0.5%. Only after the safety inspection is confirmed to be correct can the excavation operation be resumed.

[0021] The beneficial effects of the present invention are:

[0022] (1) Through the combined detection of multiple advanced detection methods, the geological information of the coal seam can be accurately grasped in advance, and gas outburst and coal body collapse accidents can be effectively prevented; through gas pre-extraction, the gas pressure and content can be effectively reduced, and the danger of gas outburst can be eliminated from the root; through the strengthening of support measures, the stability of the tunnel surrounding rock is enhanced; through the intelligent operation of the ventilation and gas monitoring system, the gas concentration can be monitored in real time to ensure that measures can be taken quickly under abnormal circumstances, comprehensively protecting the life safety of construction personnel and equipment safety, and greatly reducing the probability of gas accidents.

[0023] (2) By optimizing the excavation parameters and the real-time feedback adjustment mechanism, the TBM can operate efficiently according to the characteristics of the coal seam, reduce equipment failures and excavation stagnation time, and coordinate multiple links to reduce construction interruption time caused by safety accidents and geological problems. Continuous and stable excavation operations are achieved, effectively shortening the construction period and improving overall construction efficiency.

[0024] (3) The TBM coal excavation method provided by the present invention is applicable to coal mine tunnel excavation projects under coal seams with different gas contents and different hardness and various complex geological conditions. It has good versatility and adaptability, can bring significant economic and social benefits to the coal mine construction industry, and is worthy of vigorous promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 The present invention provides a flowchart of a safe and efficient TBM coal excavation method. DETAILED DESCRIPTION

[0027] The present invention will be clearly described below in conjunction with the accompanying drawings in the embodiments of the present invention and specific embodiments. The description here is only used to explain the present invention, but not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts, any modifications, equivalent replacements, improvements, etc., shall be included in the protection scope of the present invention.

[0028] Embodiment

[0029] As Figure 1 shown, the embodiment of the present invention provides a safe and efficient TBM tunneling and coal uncovering method, including the following steps:

[0030] S1. Advanced detection, including the following sub-steps:

[0031] S1.1. Combined detection by multiple means: When the TBM tunnels to 20 meters away from the coal seam, two detection means, namely ground penetrating radar and advanced boreholes, are enabled; among them, the ground penetrating radar uses the principle of electromagnetic wave reflection to quickly obtain the position, thickness and dip information of the coal seam, with a detection frequency of 100 - 500 MHz and a detection range of 30 - 50 meters in front of the tunneling area; the advanced boreholes are based on the detection of the ground penetrating radar to accurately verify key areas, with the number of boreholes being 3 - 5, and the borehole depth being determined according to the estimated depth of the coal seam, generally 10 - 15 meters deep into the coal seam; during the drilling process, drilling parameters such as drilling speed, torque and pressure are collected in real time, and the position and properties of the coal seam are judged in combination with the cuttings characteristics, and the collected coal samples are tested to measure parameters such as the gas content, gas pressure and coal body firmness coefficient of the coal samples.

[0032] S1.2. Data analysis and prediction: The data collected by the ground penetrating radar and advanced boreholes are transmitted to the data analysis system, and artificial intelligence algorithms are used to analyze and process the data. By establishing a geological model, the change trend of the coal seam is simulated, and possible geological anomaly areas are predicted to provide accurate geological information for subsequent construction; if abnormal situations such as sudden changes in gas content and disordered coal seam structure are found, the detection plan is adjusted in time, and more detection points are added or other auxiliary detection means are adopted.

[0033] S2. Gas pre-drainage: According to the advanced detection results, if the gas content of the coal seam exceeds 8m 3 / t Or when the gas pressure exceeds 0.74 MPa, in the area ahead of the TBM tunneling, determine the drilling positions in a fan-shaped interval arrangement. The drilling spacing is determined according to the coal seam gas permeability. The spacing in the area with good gas permeability is 3 - 5 meters, and the spacing in the area with poor gas permeability is 1 - 3 meters. The drilling depth is to penetrate the coal seam and enter the rock stratum by 0.5 - 1 meter to ensure effective gas drainage. The drainage system includes a drainage pump, pipelines, and valves. Among them, the drainage negative pressure of the drainage pump is not less than 13 kPa. Flow, concentration, and pressure sensors can be installed to detect parameters such as gas drainage concentration and flow rate in real time. According to the drainage effect, dynamically adjust the operating parameters of the drainage pump, such as rotation speed and flow rate. The pre-drainage time is not less than 30 days, and the gas content is measured continuously for 3 days and drops to 8 m 3 / t or less, and the gas pressure drops to 0.74 MPa or less before the pre-drainage can be stopped.

[0034] S3. Optimize tunneling parameters: Through sensors installed on the TBM, real-time collect data on the stress, vibration, and temperature of the coal body, as well as the operating data of the equipment. Combine these data with the physical and mechanical property data of the coal seam obtained from advanced detection, and dynamically adjust the tunneling parameters through the control system. For coal seams with different hardnesses, set different tunneling parameters: For soft coal seams, the cutterhead rotation speed is controlled at 6 - 8 r / min, the propulsion speed is 10 - 15 mm / min, and the support shoe pressure is increased to 15 - 20 MPa to reduce the impact of the cutterhead on the coal body and prevent excessive fragmentation of the coal body and subsidence of the TBM; For medium-hard coal seams, the cutterhead rotation speed is adjusted to 8 - 10 r / min, the propulsion speed is 15 - 20 mm / min, and the support shoe pressure is maintained at 12 - 15 MPa to ensure the stable operation of the equipment while ensuring the rock-breaking efficiency; For hard coal seams, the cutterhead rotation speed is increased to 10 - 12 r / min, the propulsion speed is increased to 20 - 25 mm / min, and the support shoe pressure is adjusted to 10 - 12 MPa to improve the rock-breaking efficiency.

[0035] S4. Enhanced Support: In the coal uncovering section, a combined support method of bolts, cable bolts, steel arch frames and shotcrete is adopted; for bolts, high-strength deformed steel bolts with a diameter of 22 mm and a length of 2.5 - 3 m are selected, and the row and column spacing is 0.8 - 1 m; for cable bolts, strand cable bolts with a diameter of 17.8 mm and a length of 6 - 8 m are selected, and the row and column spacing is 1.2 - 1.5 m. The deep stable rock mass of the surrounding rock is connected to the roadway surface through bolts and cable bolts to provide active support force; install steel arch frames, which are made of I-beams or U-shaped steel, with a spacing of 0.6 - 0.8 m, and support the roadway surrounding rock in a timely manner; for the shotcrete, concrete with a strength grade of C25 or above is selected and completed in three shots, with a shotcrete thickness of 15 - 20 cm: the first shot thickness is 5 - 8 cm to seal the surface of the surrounding rock; the second shot thickness is 5 - 8 cm to enhance the support strength; the third shot is sprayed to the designed thickness to ensure the integrity of the support structure; during the spraying process, the wet spraying process is adopted to reduce dust generation and improve the quality of the shotcrete.

[0036] S5. Ventilation and Gas Monitoring: Establish a perfect ventilation system, adopting a combination of forced ventilation and exhaust ventilation: install a high-power forced ventilator at the entrance of the roadway to ensure that fresh air can reach the tunneling face quickly, with an air volume of not less than 600 m 3 / min; set an exhaust ventilator at the rear of the roadway to timely discharge the gas and harmful gases generated during tunneling, and the air volume is adjusted according to the length of the roadway and the gas emission volume, generally 300 - 500 m 3 / min; set facilities such as regulating air doors and air bridges in the ventilation system to ensure the stability of the air flow. Install high-precision gas monitoring sensors at key positions such as in front of the TBM cutter head, inside the shield, and in the return air flow of the roadway to monitor the gas concentration in real time; when the gas concentration reaches 0.5%, a warning signal is issued; when the gas concentration reaches 1%, the power supply of the TBM is automatically cut off, tunneling is stopped, and the gas data is transmitted to the ground monitoring center through wireless transmission technology, so that the management personnel can timely master the gas situation underground. At the same time, start the emergency plan, notify the operators to quickly evacuate to the safe area according to the predetermined route, increase the air volume, dilute and discharge the gas until the gas concentration drops below 0.5%. After confirming that it is safe through safety inspection, tunneling operations can be resumed.

[0037] The embodiments of the present invention have been described above. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A safe and efficient TBM tunneling method for uncovering coal seams, characterized in that: It includes the following steps: S1. Advanced detection: When the TBM is approaching a coal seam at a certain distance, various advanced detection methods are adopted to accurately master parameters such as the position, thickness, dip angle, and gas content of the coal seam; S2. Gas pre-drainage: According to the results of advanced detection, if the gas content in the coal seam exceeds the standard, boreholes are drilled in the area ahead of the TBM tunneling, and the coal seam gas is pre-drained through the drainage system to reduce the gas pressure and content and eliminate the risk of gas outburst; S3. Optimize tunneling parameters: According to the physical and mechanical properties of the coal seam and the gas situation, optimize the tunneling parameters of the TBM; S4. Strengthen support: Adopt various support methods in the coal-seam uncovering section, and timely support the surrounding rock of the tunnel after excavation to prevent coal body rib spalling and roof fall; S5. Ventilation and gas monitoring: Establish a ventilation system to ensure that there is sufficient fresh air flow in the tunnel during the coal-seam uncovering process to dilute the gas concentration, and install gas monitoring sensors to monitor the gas concentration in real time.

2. The method according to claim 1, wherein: Step S1 includes the following sub-steps: S1.

1. Combined detection by multiple means: When the TBM is approaching the coal seam at a distance of 15 - 20 meters, two detection methods, namely ground penetrating radar and advanced boreholes, are enabled; among them, the ground penetrating radar can quickly obtain information on the position, thickness, and dip angle of the coal seam, with a detection frequency of 100 - 500 MHz and a detection range of 30 - 50 meters in the area ahead of tunneling; the advanced boreholes are used to accurately verify key areas on the basis of the ground penetrating radar detection. The number of boreholes is not less than 3, and the borehole depth is 10 - 15 meters; S1.

2. Data analysis and prediction: Transmit the data collected by the ground penetrating radar and advanced boreholes to the data analysis system, and use artificial intelligence algorithms to analyze and process the data. By establishing a geological model, simulate the change trend of the coal seam, predict possible geological anomaly areas, and provide accurate geological information for subsequent construction.

3. The method according to claim 2, wherein: In step S1.1, during the borehole drilling process, drilling parameters such as drilling speed, torque, and pressure are collected in real time, the position and properties of the coal seam are judged in combination with the cuttings characteristics, and the coal samples collected are tested to determine parameters such as the gas content, gas pressure, and coal body firmness coefficient of the coal samples.

4. The method according to claim 3, wherein: In step S2, according to the advanced detection results, if the coal seam gas content exceeds 8 m 3 / t or the gas pressure exceeds 0.74 MPa, in the front area of the TBM tunneling, determine the borehole positions in the form of fan-shaped intervals. The borehole spacing is determined according to the coal seam gas permeability. The spacing in the area with good permeability is 3 - 5 meters, and the spacing in the area with poor permeability is 1 - 3 meters. The borehole depth is to penetrate the coal seam and enter the rock formation by 0.5 - 1 meter.

5. The method according to claim 4, characterized in that: In step S2, the drainage system includes a drainage pump, pipelines, and valves, and the drainage negative pressure of the drainage pump is not less than 13 kPa.

6. The method according to claim 5, wherein: In step S3, through the sensors installed on the TBM, the stress, vibration, and temperature data of the coal body, as well as the operation data of the equipment, are collected in real time. Combine these data with the physical and mechanical property data of the coal seam obtained by advanced detection, and dynamically adjust the tunneling parameters through the control system.

7. The method according to claim 6, characterized in that: In step S3, different tunneling parameters are set for coal seams with different hardnesses: for soft coal seams, the cutterhead rotation speed is controlled at 6 - 8 r / min, the propulsion speed is 10 - 15 mm / min, and the support shoe pressure is increased to 15 - 20 MPa to reduce the impact of the cutterhead on the coal body and prevent excessive fragmentation of the coal body and subsidence of the TBM; for medium-hard coal seams, the cutterhead rotation speed is adjusted to 8 - 10 r / min, the propulsion speed is 15 - 20 mm / min, and the support shoe pressure is maintained at 12 - 15 MPa to ensure the stable operation of the equipment while guaranteeing the rock-breaking efficiency; for hard coal seams, the cutterhead rotation speed is increased to 10 - 12 r / min, the propulsion speed is increased to 20 - 25 mm / min, and the support shoe pressure is adjusted to 10 - 12 MPa to improve the rock-breaking efficiency.

8. The method according to claim 7, characterized in that: In step S4, in the coal uncovering section, a combined support method of bolts, cable bolts, steel arch frames and shotcrete is adopted; for bolts, high-strength threaded steel bolts with a diameter of 22 mm and a length of 2.5 - 3 m are selected, and the spacing between rows is 0.8 - 1 m; for cable bolts, strand cable bolts with a diameter of 17.8 mm and a length of 6 - 8 m are selected, and the spacing between rows is 1.2 - 1.5 m; install steel arch frames, which are made of I-beams or U-shaped steel with a spacing of 0.6 - 0.8 m; for shotcrete, concrete with a strength grade of C25 or above is selected and sprayed in 3 times, with a spraying thickness of 15 - 20 cm: the first spraying thickness is 5 - 8 cm to seal the surface of the surrounding rock; The second spraying thickness is 5 - 8 cm to enhance the support strength; The third spraying is to the designed thickness to ensure the integrity of the support structure.

9. The method according to claim 8, wherein: In step S5, a perfect ventilation system is established, adopting a combination of forced ventilation and exhaust ventilation: a high-power forced ventilator is installed at the entrance of the roadway to ensure that fresh air can quickly reach the tunneling face, and the air volume is not less than 600 m 3 / min; an exhaust ventilator is set at the rear of the roadway, and the air volume is 300 - 500 m 3 / min; Install high-precision gas monitoring sensors at key positions such as in front of the TBM cutterhead, inside the shield, and the return air flow of the roadway to monitor the gas concentration in real time.

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