Coal mine tmb engineering surrounding rock classification method based on modified bq index

Abstract

This invention discloses a method for classifying surrounding rock in coal mine TBM engineering based on a modified BQ index, belonging to the field of coal mine engineering technology. This method includes: obtaining the saturated uniaxial compressive strength and rock integrity coefficient of the rock in the roadway to be excavated; calculating and obtaining basic rock mass quality indicators; obtaining geological survey data and engineering design parameters of the roadway to be excavated, determining a first correction coefficient for quantifying the reduction in excavation efficiency, a second correction coefficient for quantifying the reduction in equipment operating efficiency, and a third correction coefficient for quantifying the reduction in construction continuity efficiency; calculating and obtaining rock mass quality indicators for coal mine TBM engineering; and determining the level of the surrounding rock by comparing it with a preset surrounding rock classification standard. This invention can quantify the reduction effect of dynamic engineering disturbances on excavation efficiency, improve the correlation between evaluation indicators and actual efficiency, and provide a scientific decision-making basis for construction organization and risk control.

Description

Technical Field

[0001] This invention relates to the field of coal mine engineering technology, and in particular to a method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index. Background Technology

[0002] Full-face tunnel boring machines, also known as "TBMs," are used in the field of efficient tunneling in coal mines. Their introduction aims to achieve highly continuous mechanized construction. However, the geological and engineering conditions underground in coal mines are extremely complex. Construction efficiency is not only controlled by the basic properties of the rock mass but also by the combined constraints of various geological and engineering factors on the equipment's continuous operation during the dynamic construction process. Currently, engineering practice generally relies on traditional surrounding rock classification systems, represented by the "Engineering Rock Mass Classification Standard" (GB / T 50218). This type of system is essentially a "stability classification" based on the static properties of the rock mass. Its core lies in evaluating the self-stabilizing capacity of the surrounding rock under engineering disturbances through inherent parameters such as rock strength and integrity, and providing a basis for support design.

[0003] However, this surrounding rock classification system has fundamental limitations in predicting the continuous tunneling efficiency of coal mine TBMs. Specifically, traditional classification methods provide an evaluation of the rock mass condition but fail to effectively translate it into a prediction of the performance of the coal mine TBM during the "construction process." During coal mine TBM construction, numerous factors not directly related to rock mass stability can significantly reduce effective tunneling time by inducing equipment shutdowns, reducing slag removal efficiency, and forcibly interleaving auxiliary processes.

[0004] Therefore, directly applying traditional rock mass classification results to guide TBM construction in coal mines often leads to the contradictory phenomenon of good classification results but difficult tunneling. This results in construction plans, selected equipment models, and budgeted schedules based on the classification results being completely out of touch with reality. This not only fails to achieve efficient tunneling of coal mine TBMs, leading to a significant increase in costs, but also increases safety risks due to the failure to anticipate the actual operational difficulties. Summary of the Invention

[0005] This invention aims to address at least one of the technical problems existing in the prior art. To this end, this invention proposes a method for classifying the surrounding rock in coal mine TBM engineering based on a modified BQ index. This method can quantify the reduction effect of these dynamic engineering disturbances on pure tunneling efficiency, thereby improving the correlation between evaluation indicators and actual efficiency.

[0006] The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to embodiments of the present invention includes:

[0007] S1: Obtain the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient of the roadway to be excavated; S2: Calculate and obtain the basic quality indicators of the rock mass based on the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient; S3: Obtain geological survey data and engineering design parameters of the roadway to be excavated, and determine the first correction coefficient for quantifying the reduction of excavation efficiency due to the synergistic effect of hydrogeology and excavation conditions, the second correction coefficient for quantifying the reduction of equipment operation efficiency due to roadway spatial attitude, and the third correction coefficient for quantifying the reduction of construction continuity efficiency due to adjacent coal seam gas occurrence and structural development. S4: Based on the basic rock mass quality index, the first correction coefficient, the second correction coefficient, and the third correction coefficient, calculate and obtain the rock mass quality index for coal mine TBM engineering; S5: Based on the rock mass quality indicators of the coal mine TBM project, and in accordance with the preset surrounding rock classification standards, determine the level of the surrounding rock of the coal mine TBM project.

[0008] The invention offers at least the following beneficial effects: By systematically analyzing the main performance constraints in coal mine TBM construction, the invention accurately identifies three dynamic interference sources that distort traditional basic rock mass quality indicators: the synergistic effect of hydrogeological conditions and tunneling direction, the influence of roadway spatial attitude, and the combined effect of adjacent coal seam gas risk and geological structure. Furthermore, this invention transforms these dynamic interference sources into quantifiable performance reduction coefficients. Specifically, a first correction coefficient quantifies the combined impact of hydrogeological conditions and tunneling conditions on the cutterhead's working state and slag removal efficiency; a second correction coefficient quantifies the constraint of roadway inclination angle on equipment propulsion stability; and a third correction coefficient quantifies the impact of safety measures such as gas control and structural exploration on construction continuity. Therefore, by incorporating the first, second, and third correction coefficients into the rock mass quality evaluation process, a rock mass quality index for coal mine TBM engineering is constructed that goes beyond the static description of the rock mass's own properties. This index directly characterizes the relative tunneling efficiency level that coal mine TBMs can achieve under specific geological and engineering conditions, thereby achieving the goal of directly predicting the actual tunneling efficiency of coal mine TBMs in complex environments and providing a scientific basis for equipment selection, construction organization, and risk prevention and control.

[0009] According to some embodiments of the present invention, in S3, determining the first correction coefficient includes: determining the tunnel excavation direction; obtaining the tunnel fissure water pressure, the water output of the tunnel length at a preset distance, and the water output state, and determining the water-bearing capacity level of the surrounding rock; and determining the value of the first correction coefficient according to the correspondence between the tunnel excavation direction and the water-bearing capacity level of the surrounding rock.

[0010] According to some embodiments of the present invention, the tunnel excavation direction includes downhill excavation and non-downhill excavation.

[0011] According to some embodiments of the present invention, the water-bearing capacity of the surrounding rock includes weak water-bearing, moderately weak water-bearing, and strong water-bearing.

[0012] According to some embodiments of the present invention, in S3, determining the second correction coefficient includes: obtaining the roadway excavation dip angle; obtaining the absolute value of the dip angle based on the roadway excavation dip angle; determining the dip angle level of the roadway based on the absolute value of the dip angle; and determining the value of the second correction coefficient based on the dip angle level.

[0013] According to some embodiments of the present invention, the dip angle class includes near-horizontal roadways, gently inclined roadways, and steeply inclined roadways.

[0014] According to some embodiments of the present invention, when the tunnel excavation dip angle is within the dip angle range corresponding to a gently inclined tunnel, the value of the second correction coefficient increases linearly with the increase of the absolute value of the dip angle.

[0015] According to some embodiments of the present invention, determining the third correction coefficient includes: obtaining the gas pressure and gas content of the adjacent coal seam, determining whether the adjacent coal seam has an outburst risk based on the gas pressure and gas content of the adjacent coal seam, and obtaining a first result; obtaining geological structure distribution parameters, determining whether the roadway to be excavated is in a fault influence zone based on the geological structure distribution parameters, and obtaining a second result; and determining the value of the third correction coefficient based on the first result and the second result.

[0016] According to some embodiments of the present invention, the criteria for determining the hazard are: gas pressure P ≥ 0.74 MPa or gas content W ≥ 8 m³ / t.

[0017] According to some embodiments of the present invention, in S5, the rock mass quality index for coal mine TBM engineering is BQ. TBM The grading standard is as follows: Grade I surrounding rock: BQ TBM >550; Class II surrounding rock: 450 <BQ TBM ≤550; Class III surrounding rock: 350<BQ TBM ≤450; Class IV surrounding rock: 250<BQ TBM ≤350; Class V surrounding rock: BQ TBM ≤250; where BQ TBM These are the rock mass quality indicators for TBM (Tube-to-Membrane) engineering in coal mines.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a flowchart illustrating the surrounding rock classification method for coal mine TBM engineering based on the modified BQ index in this specific embodiment. Figure 2 This is a scatter plot showing the correlation between basic rock mass quality indicators and average daily advance of coal mine TBMs in this invention. Figure 3 The modified rock mass quality index BQ for coal mine TBM engineering in this invention. TBM Scatter plot showing the correlation between the average daily footage of TBMs in coal mines and the actual footage. Detailed Implementation

[0020] In the description of this invention, it should be understood that the orientation descriptions, such as up, down, left, right, front, back, etc., are based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0021] In the description of this invention, "several" means one or more, "multiple" means two or more, "greater than," "less than," "exceeding," etc. are understood to exclude the stated number, and "above," "below," "within," etc. are understood to include the stated number. If "first," "second," etc. are used in the description, they are only configured to distinguish technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0022] In the description of this invention, unless otherwise explicitly defined, terms such as "set", "install", and "connect" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this invention in conjunction with the specific content of the technical solution.

[0023] Please refer to Figure 1 This embodiment discloses a method for classifying surrounding rock in coal mine TBM engineering based on a modified BQ index, including: S1: Obtain the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient of the roadway to be excavated; S2: Calculate and obtain the basic quality indicators of the rock mass based on the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient; S3: Obtain geological survey data and engineering design parameters of the roadway to be excavated, and determine the first correction coefficient for quantifying the reduction of excavation efficiency due to the synergistic effect of hydrogeology and excavation conditions, the second correction coefficient for quantifying the reduction of equipment operation efficiency due to roadway spatial attitude, and the third correction coefficient for quantifying the reduction of construction continuity efficiency due to adjacent coal seam gas occurrence and geological structure. S4: Based on the basic rock mass quality index, the first correction coefficient, the second correction coefficient, and the third correction coefficient, calculate and obtain the rock mass quality index for coal mine TBM engineering; S5: Based on the rock mass quality indicators of the coal mine TBM project, and in accordance with the preset surrounding rock classification standards, determine the level of the surrounding rock of the coal mine TBM project.

[0024] Specifically, the saturated uniaxial compressive strength of rock and the rock mass integrity coefficient are geological exploration data, which are mainly obtained through core drilling, geological specifications, and laboratory experiments.

[0025] In the technical solution of this invention, by systematically analyzing the main performance constraints in TBM construction in coal mines, three dynamic interference sources that cause distortion of traditional basic rock mass quality indicators are identified: the synergistic effect of hydrogeological conditions and tunneling direction, the influence of roadway spatial attitude, and the combined effect of adjacent coal seam gas risk and geological structure. For these dynamic interference sources, this invention transforms them into quantifiable performance reduction coefficients. Specifically, a first correction coefficient quantifies the comprehensive impact of the combination of hydrogeological and tunneling conditions on the cutterhead working state and slag removal efficiency; a second correction coefficient quantifies the constraint of roadway inclination angle on equipment propulsion stability; and a third correction coefficient quantifies the impact of safety measures such as gas control and structural exploration on construction continuity. Therefore, by incorporating the first correction coefficient K1, the second correction coefficient K2, and the third correction coefficient K3 into the rock mass quality evaluation process, a rock mass quality index for coal mine TBM engineering is constructed that goes beyond the static description of the rock mass's own properties. Instead, it directly characterizes the relative tunneling efficiency level that coal mine TBMs can achieve under specific geological and engineering conditions, thereby achieving the goal of directly predicting the actual tunneling efficiency of coal mine TBMs in complex environments and providing a scientific decision-making basis for equipment selection, construction organization, and risk prevention and control.

[0026] It should be further noted that the parameters required by this invention are all mandatory test items in conventional geological exploration and design of coal mines. No additional testing methods are required. It has the characteristics of low cost, easy implementation, and strong operability, and is easy for on-site technicians to quickly master and apply.

[0027] In some specific embodiments of the present invention, in S2, the calculation formula for the basic quality index of the rock mass includes:

[0028] In the formula, This represents the saturated uniaxial compressive strength of rock, expressed in MPa. This is the rock mass integrity coefficient.

[0029] Preferably, when When, substitute Perform calculations; when When, substitute Perform the calculation.

[0030] In some specific embodiments of the present invention, in S3, determining the first correction coefficient includes: determining the tunnel excavation direction; obtaining the fissure water pressure of the surrounding rock, the water output and water output status of the tunnel length over a preset distance, and determining the water-bearing level of the surrounding rock based on the fissure water pressure of the surrounding rock, the water output and water output status of the tunnel length over a preset distance; and determining the value of the first correction coefficient based on the correspondence between the tunnel excavation direction and the water-bearing level of the surrounding rock.

[0031] In some specific embodiments of the present invention, the tunnel excavation direction includes downhill excavation and non-downhill excavation, wherein the non-downhill excavation includes uphill excavation and horizontal excavation.

[0032] Specifically, the water-bearing capacity of the surrounding rock is classified according to the fissure water pressure of the surrounding rock, the water output per 10m of tunnel length, and the water output status. It includes three levels: weak water-bearing capacity, moderately weak water-bearing capacity, and strong water-bearing capacity. The water-bearing capacity of the surrounding rock is classified according to the fissure water pressure p (MPa), the outflow rate Q (L / min·10m) per 10m tunnel length, and the outflow state: when the surrounding rock is damp or dripping, and p≤0.1MPa or Q≤25L / (min·10m), it is classified as weakly water-bearing; when the surrounding rock is raining or flowing linearly, and 0.1<p≤0.5MPa or 25<Q≤125L / (min·10m), it is classified as moderately water-bearing; when the surrounding rock is gushing, and p>0.5MPa or Q>125L / (min·10m), it is classified as strongly water-bearing.

[0033] Specifically, the water inflow in the tunnel is geological survey data, which is mainly obtained through hydrogeological observations; the tunnel excavation inclination angle is the designed excavation inclination angle of the tunnel axis, which is mainly obtained from the tunnel construction design drawings.

[0034] It should be noted that the same water inflow has drastically different impacts and mechanisms on the efficiency of coal mine TBMs under different tunneling directions. This phenomenon is a unique engineering problem in coal mine TBM construction. Specifically, in uphill tunneling, groundwater can flow naturally backward along the roadway under gravity, with minimal impact on the accumulation in the working area in front of the cutterhead, and relatively limited disruption to the continuous tunneling rhythm. Conversely, in downhill tunneling, groundwater converges in front of the working face under gravity, easily forming water accumulation in the cutterhead area, leading to rock cuttings becoming muddy and severely clogging the slag removal system and cutterhead openings. This not only drastically reduces rock breaking and slag removal efficiency but also triggers frequent shutdowns for cleaning, fundamentally reducing the effective tunneling time upon which coal mine TBMs rely for operation.

[0035] Therefore, when the tunnel is in the downhill excavation condition: If the surrounding rock is weakly water-bearing, the value of K1 ranges from 0.4 to 0.6; If the surrounding rock is moderately to weakly water-bearing, the value of K1 ranges from 0.7 to 0.9. If the surrounding rock is highly water-rich, K1 is set to 1.0; When the tunnel is not in a downhill tunneling condition: If the surrounding rock is weakly water-bearing, K1 is set to 0; If the surrounding rock is moderately to weakly water-bearing, the value of K1 ranges from 0 to 0.1; If the surrounding rock is highly water-rich, the value of K1 ranges from 0.1 to 0.2.

[0036] In some specific embodiments of the present invention, in S3, determining the second correction coefficient includes: obtaining the roadway excavation dip angle; obtaining the absolute value of the dip angle based on the roadway excavation dip angle; determining the dip angle level of the roadway based on the absolute value of the dip angle; and determining the value of the second correction coefficient based on the dip angle level.

[0037] In some specific embodiments of the present invention, the inclination angle level includes near-horizontal roadways, gently inclined roadways, and steeply inclined roadways. The inclination angle level is determined based on the absolute value of the excavation inclination angle, which is α. When |α|≤6°, the roadway to be excavated is determined to be a near-horizontal roadway; when 6°<|α|≤16°, the roadway to be excavated is determined to be a gently inclined roadway; and when |α|>16°, the roadway to be excavated is determined to be a steeply inclined roadway.

[0038] It should be noted that the tunneling efficiency of a coal mine TBM depends on the stability of the propulsion system and the smoothness of the muck removal system. In near-horizontal roadways, the equipment easily achieves stable load, and the muck can be transported relatively smoothly by belt conveyors. As the inclination angle increases, especially in steeply inclined roadways, the component of the equipment's gravity along the propulsion direction changes significantly. Consequently, during uphill tunneling, this component becomes an additional resistance that needs to be overcome, exacerbating the load and energy consumption of the propulsion system; during downhill tunneling, although this component helps with propulsion, it poses a severe challenge to the attitude control and braking systems. At the same time, changes in inclination angle directly affect the self-weight transport characteristics of the muck, potentially leading to problems such as belt slippage, muck backflow, or blockage at transfer points, thereby triggering a chain reaction of shutdowns. Therefore, this invention uses the tunnel inclination angle as the core parameter of the second correction coefficient, quantifying this loss caused by spatial attitude and independent of the rock mass's own properties, thus truly reflecting the actual performance that a coal mine TBM can achieve at a specific inclination angle.

[0039] Specifically, considering the impact of slope on the tunneling efficiency of TBMs in coal mines, K2 is set to 0 when the roadway is near horizontal; K2 is set to 0 to 0.4 when the roadway is gently inclined; and K2 is set to 0.4 to 0.7 when the roadway is steeply inclined.

[0040] Furthermore, when the tunnel excavation dip angle is within the dip angle range corresponding to a gently inclined tunnel, the value of the second correction coefficient increases linearly with the increase of the absolute value of the dip angle.

[0041] In some specific embodiments of the present invention, determining the third correction coefficient includes: obtaining the gas pressure and gas content of the adjacent coal seam, determining whether the adjacent coal seam has an outburst risk based on the gas pressure and gas content of the adjacent coal seam, and obtaining a first result; obtaining geological structure distribution parameters, determining whether the roadway to be excavated is in a fault influence zone based on the geological structure distribution parameters, and obtaining a second result; and determining the value of the third correction coefficient based on the first result and the second result.

[0042] In coal mine safety regulations, the risk of gas outbursts in adjacent coal seams and geological structures are typically managed as major safety threats, with countermeasures primarily focused on disaster prevention. However, for TBM (Tube-Mounted Machine) construction in coal mines, which aims for high continuity, these safety control measures can forcefully interrupt planned tunneling operations, directly reducing effective pure tunneling time. Specifically, when a roadway is adjacent to a coal seam with a high risk of outbursts, strict anti-outburst measures must be implemented, which usually means that the TBM needs to be shut down for an extended period or perform non-tunneling operations. When traversing fault zones or other geological structures, grouting reinforcement and advanced support are often required in advance to address risks such as fractured surrounding rock and sudden water inrushes, severely disrupting the continuous tunneling rhythm. Especially when gas risk and geological structures coexist, the required composite control measures will result in even longer process intervals and lower tunneling efficiency. Therefore, this invention introduces a third correction coefficient to transform the process-related impact of the inevitable interruption of construction continuity caused by gas control and structural treatment into a quantitative reduction item for the rock mass excavability index. This allows the final classification result to not only reflect the mechanical conditions of the rock mass itself, but also to predict the time cost that must be paid for complying with safety regulations, thereby providing a precise decision-making basis for coal mine TBM construction organization, schedule planning and resource allocation.

[0043] In some specific embodiments of the present invention, the gas pressure and gas content are geological exploration data, which are mainly obtained through gas geological maps. Specifically, when the gas pressure P ≥ 0.74 MPa or the gas content W ≥ 8 m³ / t, the adjacent coal seam is determined to have an outburst risk.

[0044] It should be noted that if the roadway to be excavated is not located in a fault-affected area, then it is in a fault-free area. Considering the impact of coal mine safety regulations on outburst prevention and exploration measures for outburst-prone coal seams and fault zones on excavation efficiency, when adjacent coal seams pose an outburst risk: If the tunnel is located in the fault-affected zone, K3 is taken as 1.0 to 1.5; If the tunnel is located in a fault-free area, K3 takes a value between 0 and 0.5; When the adjacent coal seam does not pose a risk of outburst: If the tunnel is located in the fault-affected zone, K3 is taken as 0.5 to 1.0; If the tunnel is located in a fault-free area, K3 is 0.

[0045] In some specific embodiments of the present invention, in S4, the calculation formula for the rock mass quality index of coal mine TBM engineering is as follows:

[0046] In the formula, These are the rock mass quality indicators for TBM (Tube Milling) projects in coal mines. These are the basic values ​​for the fundamental quality indicators of the rock mass. C K1 is the weighting coefficient, with a value of 100; K2 is the first correction coefficient, K3 is the second correction coefficient, and K4 is the third correction coefficient.

[0047] In some specific embodiments of the present invention, in S5, the rock mass quality index of the coal mine TBM engineering is BQ. TBM The classification standards for coal mine TBM projects are shown in the table below: <![CDATA[BQ of engineering rock mass for coal mine TBM TBM > Surrounding rock level Expected tunneling efficiency ＞550 I quick 550-451 II Faster 450-351 III medium 350-251 IV Slower ≤250 V extremely slow The following reference Figures 2 to 3 The content, combined with specific embodiments, further details the surrounding rock classification method for coal mine TBM engineering based on the modified BQ index.

[0048] The following detailed description of the specific implementation of this invention is based on a real-world engineering case study of a deep rock tunnel in a mining area. The target tunnel is approximately 2000 meters long and traverses various geological conditions. This embodiment selects two representative sections for application verification.

[0049] Working Condition 1: Conventional Geological Section; (1) Based on the geological survey report and construction design documents of this section of the tunnel, obtain the parameters required for evaluation. The surrounding rock is mainly fine sandstone, and the saturated uniaxial compressive strength of the rock was measured in the laboratory. Rock mass integrity coefficient The tunnel was designed to be excavated uphill, with a slope of... Hydrogeological investigations indicate that there is no water inrush in this section, meaning the water pressure in the fissures of the surrounding rock of the tunnel is low. The gas parameters of the adjacent coal seams are all below the critical value for outburst risk, and this section is located in a fault-free zone.

[0050] (2) Calculate the basic quality index BQ of the rock mass, i.e.:

[0051] (3) Determine the correction factor: For non-downhill tunneling and no water inrush, take The roadway slope |α| = 3° ≤ 6°, classifying it as a near-horizontal roadway. Therefore, we take... 0; The adjacent coal seam poses no outburst risk and is not affected by faults, therefore, [the following is taken]: .

[0052] (4) Calculate the rock mass quality index BQ for coal mine TBM engineering TBM ,Right now:

[0053] (5) According to the classification standard of coal mine TBM project in Table 1, the surrounding rock of this section is determined to be Class II surrounding rock.

[0054] (6) It should be noted that in actual construction, the TBM in this section of the coal mine has an average daily advance of more than 15 meters, and the tunneling efficiency is relatively high. The results of this method are consistent with the actual situation.

[0055] Working Condition 2: Complex Geological Section; (1) The surrounding rock lithology in this section is mainly siltstone. The saturated uniaxial compressive strength of the rock was measured. Rock mass integrity coefficient The tunnel was designed for downhill excavation with a gradient of [missing information]. Hydrogeological observations indicate water inrush and high water pressure in the fissures of the surrounding rock in the tunnel. The surrounding rock was determined to be highly water-rich; tests on the adjacent coal seam showed that the gas pressure and content did not reach the critical value for outburst danger, and the section was located in a fault-free zone.

[0056] (2) Calculate the basic quality index BQ of the rock mass, i.e.:

[0057] It should be noted that, according to the "Engineering Rock Mass Classification Standard", 372.5 belongs to Class III surrounding rock, and theoretically, the TBM tunneling efficiency in coal mines is moderate.

[0058] (3) The tunnel is excavated downhill and the surrounding rock is highly water-rich. The roadway slope |α| = 17° > 16°, classifying it as a steeply inclined roadway. Therefore, we take... 0.7; The adjacent coal seam poses no outburst risk and is not affected by faults, therefore, [the value is taken as...]. .

[0059] (4) Calculate the rock mass quality index BQ for coal mine TBM engineering TBM ,Right now:

[0060] (5) According to the classification standard of coal mine TBM project in Table 1, the surrounding rock of this section is determined to be Class V surrounding rock.

[0061] (6) In actual TBM construction in coal mines, this section of the roadway experienced severe water accumulation and muddy rock formation in front of the cutterhead due to strong water inrush during downhill excavation. This frequently blocked the slag removal system, requiring repeated shutdowns for cleaning. The monthly advance was less than 90 meters, making excavation extremely difficult. Traditional rock mass quality indicators classified it as Class III surrounding rock, which significantly overestimated its excavability. However, the method of this invention accurately classified it as Class V surrounding rock, which is highly consistent with the actual construction efficiency under adverse conditions. This demonstrates the accurate predictive ability of this invention for TBM excavation efficiency in complex coal mine geological conditions.

[0062] Furthermore, Figure 2 This is a scatter plot showing the correlation between basic rock mass quality indicators and average daily advance of coal mine TBMs in this invention. Figure 3 The modified rock mass quality index BQ for coal mine TBM engineering in this invention. TBM Scatter plot showing the correlation between the average daily footage of TBMs in coal mines and the actual footage.

[0063] As can be seen from the two contrasting working conditions and accompanying drawings, the rock mass classification method for coal mine TBM engineering based on the modified BQ index provided by this invention systematically introduces and quantifies the reduction effect of dynamic construction constraints such as groundwater and roadway dip angle on tunneling efficiency, thereby improving the obtained rock mass quality index BQ for coal mine TBM engineering. TBM Compared with traditional methods, the correlation between the indicators and classification results and the actual tunneling efficiency of coal mine TBMs is significantly improved. This method can not only more accurately evaluate the actual excavability of the surrounding rock in coal mine TBM construction scenarios, but also effectively identify potentially inefficient and high-risk sections caused by special geological and working condition combinations. Therefore, it provides a more scientific, intuitive and quantitative basis for equipment adaptability assessment, tunneling parameter optimization, construction period prediction and risk prevention and control strategy formulation in coal mine TBM projects.

[0064] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0065] Of course, the present invention is not limited to the above-described embodiments. Those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A method for classifying surrounding rock in coal mine TBM engineering based on a modified BQ index, characterized in that, include: S1: Obtain the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient of the roadway to be excavated; S2: Calculate and obtain the basic quality indicators of the rock mass based on the saturated uniaxial compressive strength of the rock and the rock mass integrity coefficient; S3: Obtain geological survey data and engineering design parameters of the roadway to be excavated, and determine the first correction coefficient for quantifying the reduction of excavation efficiency due to the synergistic effect of hydrogeology and excavation conditions, the second correction coefficient for quantifying the reduction of equipment operation efficiency due to roadway spatial attitude, and the third correction coefficient for quantifying the reduction of construction continuity efficiency due to adjacent coal seam gas occurrence and structural development. S4: Based on the basic rock mass quality index, the first correction coefficient, the second correction coefficient, and the third correction coefficient, calculate and obtain the rock mass quality index for the coal mine TBM project; S5: Based on the rock mass quality indicators of the coal mine TBM project, and in accordance with the preset surrounding rock classification standards, determine the level of the surrounding rock of the coal mine TBM project.

2. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 1, characterized in that, In S3, determining the first correction coefficient includes: Determine the direction of tunnel excavation; The fissure water pressure of the surrounding rock in the tunnel, the water output and water output status at a preset distance, are obtained to determine the water-bearing level of the surrounding rock. The value of the first correction coefficient is determined based on the correspondence between the tunnel excavation direction and the water-bearing capacity of the surrounding rock.

3. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 2, characterized in that, The tunnel excavation direction includes downhill excavation and non-downhill excavation.

4. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 3, characterized in that, The water-bearing properties of the surrounding rock are classified into weak water-bearing, moderately weak water-bearing, and strong water-bearing.

5. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 1, characterized in that, In S3, determining the second correction factor includes: Obtain the tunnel excavation dip angle, and then obtain the absolute value of the dip angle based on the tunnel excavation dip angle; The dip angle grade of the roadway is determined based on the absolute value of the dip angle; The value of the second correction factor is determined based on the tilt angle rating.

6. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 5, characterized in that, The dip angle classification includes near-horizontal roadways, gently inclined roadways, and steeply inclined roadways.

7. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 6, characterized in that, When the tunnel excavation angle is within the angle range corresponding to a gently inclined tunnel, the value of the second correction coefficient increases linearly with the increase of the absolute value of the angle.

8. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 1, characterized in that, Determining the third correction factor includes: Obtain the gas pressure and gas content of the adjacent coal seam, and determine whether the adjacent coal seam has an outburst risk based on the gas pressure and gas content, and obtain the first result; Obtain geological structure distribution parameters, determine whether the tunnel to be excavated is in a fault-affected area based on the geological structure distribution parameters, and obtain a second result; The value of the third correction factor is determined based on the first and second results.

9. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 8, characterized in that, The criteria for determining a prominent hazard are: gas pressure P ≥ 0.74 MPa or gas content W ≥ 8 m³ / t.

10. The method for classifying surrounding rock in coal mine TBM engineering based on the modified BQ index according to claim 9, characterized in that, In S5, the rock mass quality index of the coal mine TBM project is BQ. TBM The grading criteria are as follows: Class I surrounding rock: BQ TBM >550; Class II surrounding rock: 450 < BQ TBM ≤550; Class III surrounding rock: 350 < BQ TBM ≤450; Class IV surrounding rock: 250 < BQ TBM ≤350; Class V surrounding rock: BQ TBM ≤250; Among them, BQ TBM These are the rock mass quality indicators for TBM (Tube-to-Membrane) engineering in coal mines.

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