A method for zonal differential control of surrounding rock of multi-layer underlying roadway under dynamic pressure influence

Abstract

The application discloses a kind of multi-layer position underlying roadway surrounding rock zoning difference control methods under dynamic pressure influence, by constructing working face mining floor stress distribution mechanics model, the load distribution of mining stress concentration zone and stress recovery zone is calculated;The stress state of different positions of mining floor surrounding rock is calculated, and the floor surrounding rock is zoned accordingly, and according to the floor surrounding rock zoning result, the underlying roadway of different positions is correspondingly zoned and divided, to obtain high dynamic pressure roadway, medium dynamic pressure roadway and low dynamic pressure roadway;And different technical measures are used for high dynamic pressure roadway, medium dynamic pressure roadway and low dynamic pressure roadway respectively to control the stability of roadway surrounding rock;Finally, the surrounding rock condition of underlying roadway under different dynamic pressure influence is monitored in real time, and the surrounding rock control measures are dynamically optimized according to the monitoring result.The application is aimed at multi-layer position underlying large roadway under dynamic pressure influence, and through "deep-shallow-surface" multiple surrounding rock control measures, the stability of surrounding rock in each region is effectively controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel surrounding rock control, and in particular to a method for controlling zoning differences of multi-layer underlying tunnel surrounding rock under the influence of dynamic pressure. Background Art

[0002] In the process of mining close to coal seams, in order to overcome the difficulties of continuous mining and excavation, the lower coal roadway needs to be arranged below the unmined upper coal seam. Under the influence of the dynamic pressure of the mining face, the mining stress is transmitted between the rock layers, affecting the stress distribution of the surrounding rock mass. The surrounding rock of the underlying roadway often exhibits weak rheological characteristics, exacerbating the development of surrounding rock deformation, cross-section shrinkage, and support structure failure. The mechanical properties and stability of the roadway surrounding rock will be weakened. In this state, if the support structure system fails to keep up with the range of changes in the surrounding rock stress of the dynamic pressure roadway, and if appropriate surrounding rock control technical measures are not implemented in time, the roadway will experience a certain degree of surrounding rock deformation, cross-section convergence, and form a large surrounding rock loosening zone, resulting in instability and failure, which will restrict the normal use of the roadway and seriously affect the safe and efficient production operations of the coal mine.

[0003] The difficulties in controlling the stability of the surrounding rock of the underlying roadway are mainly manifested in the unclear mine pressure, large deformation of the surrounding rock, and difficulty in controlling the surrounding rock stability. At present, the common method of controlling the stability of the surrounding rock of the underlying roadway is to use a single form of reinforcement support such as anchor rods, anchor cables, scaffolding, and grouting on the original support. Under the influence of dynamic pressure, the surrounding rock of the bottom plate roadway is extremely broken. Ordinary anchor rods and anchor cables are difficult to anchor to stable rock layers, and cannot form an effective support and reinforcement for the broken roadway surrounding rock structure; passive support methods such as scaffolding have weak long-term control capabilities for roadway deformation and cannot effectively control the roadway bottom heave problem under the influence of dynamic pressure; grouting reinforcement methods are widely used in roadway roof support with broken surrounding rock, and the surrounding rock stability control effect is better, but the grouting cost is high and the natural fissure grouting effect is poor. Therefore, it can be seen that it is difficult to achieve a better surrounding rock control effect by adopting only a single control method to control the surrounding rock stability of the underlying roadway. Summary of the Invention

[0004] The present invention aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, the first purpose of the present invention is to propose a method for differential control of surrounding rock zones in multi-layered underground tunnels under the influence of dynamic pressure. For multi-layered underground tunnels under the influence of dynamic pressure, multiple surrounding rock control measures (deep-shallow-surface) are used to ensure that the stability of the surrounding rock in each area is effectively controlled. The surrounding rock control status of the underground tunnel under the influence of dynamic pressure is monitored in real time, thereby effectively verifying the effectiveness of tunnel surrounding rock control. The tunnel surrounding rock control scheme is dynamically optimized based on the monitoring results, thereby improving the effectiveness and reliability of tunnel surrounding rock control.

[0005] To achieve the above objectives, a first embodiment of the present invention proposes a method for controlling the differences in surrounding rock zoning of a multi-layered underlying roadway under the influence of dynamic pressure, comprising:

[0006] S1: establishing a stress distribution mechanical model of the mining floor of the working face, determining the width of the working face, the range of the stress concentration zone, and the range of the stress recovery zone based on the stress distribution mechanical model, on-site geological conditions, and stress distribution characteristics of the surrounding rock of the stope, and calculating the load distribution of the stress concentration zone and the stress recovery zone;

[0007] S2: Calculate the stress state of the surrounding rock of the mining floor at different positions, and divide the surrounding rock of the mining floor into zones according to the stress state to obtain a high dynamic pressure influence zone, a medium dynamic pressure influence zone, and a low dynamic pressure influence zone;

[0008] S3: Based on the zoning results of the floor surrounding rock, the underlying roadways at different locations are divided into corresponding zones to obtain high dynamic pressure roadways, medium dynamic pressure roadways, and low dynamic pressure roadways;

[0009] S4: For the high dynamic pressure roadway, in the early stage of mining operation when the high dynamic pressure roadway is affected by the dynamic pressure, shallow grouting reinforcement of the roadway, roadway surface reinforcement support and deep advanced pressure relief of the mining floor are used to control the stability of the surrounding rock of the high dynamic pressure roadway;

[0010] S5: For the medium dynamic pressure roadway, in the early stage of mining operation when the medium dynamic pressure roadway is affected by dynamic pressure, shallow grouting reinforcement and roadway surface reinforcement support technology are used to control the stability of the surrounding rock of the medium dynamic pressure roadway;

[0011] S6: For the low dynamic pressure roadway, in the early stage of mining operation when the low dynamic pressure roadway is affected by dynamic pressure, the roadway surface reinforcement support technology is used to control the stability of the surrounding rock of the low dynamic pressure roadway;

[0012] S7: Real-time monitoring of surrounding rock conditions of the underlying roadway under the influence of different dynamic pressures, and dynamic optimization of surrounding rock control measures of the underlying roadway based on the monitoring results.

[0013] According to the method for controlling the difference of surrounding rock zoning of multi-layered underlying roadways under the influence of dynamic pressure in an embodiment of the present invention, a mechanical model of the stress distribution of the mining floor of the working face is established by constructing a working face, and the load distribution of the mining stress concentration zone and the stress recovery zone is calculated; the stress state at different positions of the mining floor surrounding rock is calculated, and the floor surrounding rock is partitioned accordingly to obtain high dynamic pressure influence zone, medium dynamic pressure influence zone and low dynamic pressure influence zone; according to the floor surrounding rock zoning results, the underlying roadways at different positions are divided into corresponding zones to obtain high dynamic pressure roadways, medium dynamic pressure roadways and low dynamic pressure influence zone. Low dynamic pressure roadway; for high dynamic pressure roadway, shallow grouting reinforcement, roadway surface reinforcement support and deep advanced unloading of mining floor are used to control the roadway surrounding rock stability; for medium dynamic pressure roadway, shallow grouting reinforcement and roadway surface reinforcement support are used to control the roadway surrounding rock stability; for low dynamic pressure roadway, roadway surface reinforcement support is used to control the roadway surrounding rock stability; finally, the surrounding rock conditions of the underlying roadway under different dynamic pressures are monitored in real time, and the surrounding rock control measures are dynamically optimized based on the monitoring results. Therefore, this method ensures that the surrounding rock stability of each area is effectively controlled for multi-layered underlying large roadways under the influence of dynamic pressure through multiple surrounding rock control measures of "deep-shallow-surface"; and the surrounding rock control conditions of the underlying roadway under the influence of dynamic pressure are monitored in real time, thereby effectively verifying the roadway surrounding rock control effect, and dynamically optimizing the roadway surrounding rock control scheme based on the monitoring results, thereby improving the effectiveness and reliability of roadway surrounding rock control.

[0014] In addition, the method for controlling the difference in surrounding rock zones of multi-layered underlying roadways under the influence of dynamic pressure according to the above embodiment of the present invention may also have the following additional technical features:

[0015] According to one embodiment of the present invention, in step S1, the stress distribution mechanical model of the mining floor of the working face is: coal seam mining causes redistribution of rock stress around the mining space, one side of the coal body is the goaf, and the other side of the coal body is a solid, and the supporting pressure acting on the coal body is approximately triangularly distributed; wherein, the front of the working face is divided into the stress concentration zone and the original rock stress zone, and the rear of the working face is divided into the stress recovery zone and the original rock stress zone; the boundary loads of the stress recovery zone and the stress concentration zone are both monotonically increasing or decreasing linear loads, and the load of the original rock stress zone is a uniformly distributed load; the coal body in front of the working face and the surrounding rock of the coal seam floor are regarded as elastic bodies.

[0016] According to one embodiment of the present invention, the calculation formula of the stress recovery zone range is as follows:

[0017] L3=L2(K-1)-2L1

[0018] Wherein, L3 is the range of the stress recovery area; L2 is the range of the stress concentration area; L1 is the width of the working surface; K is the stress concentration coefficient;

[0019] The stress concentration area includes a stress increase area and a stress reduction area;

[0020] The load distribution calculation formula corresponding to the stress increase area is:

[0021]

[0022] Among them, L 21 is the range of the stress-increased zone; γ is the bulk density of the overlying rock layer; H is the burial depth;

[0023] The load distribution calculation formula corresponding to the stress reduction area is:

[0024]

[0025] The load distribution calculation formula corresponding to the stress recovery zone is:

[0026]

[0027] According to one embodiment of the present invention, in step S2, a point ε is taken on the x-axis of the stress distribution mechanics model, its distance from the origin is ε, and its differential dε is taken, then the load on this differential body is dq i =q i dε, and regard it as a small concentrated force, then the horizontal and vertical distances from a certain position in the floor rock layer to dε are x-ε and y respectively. The stress state at different positions of the mining floor surrounding rock is calculated by the following formula:

[0028]

[0029] Among them, σ x is the horizontal stress; σ y is the vertical stress; τ χy is the shear stress; x and y are the horizontal and vertical coordinates of a certain position in the bottom rock layer; L is the stress segment corresponding to the front and back of the working surface; q L is the load corresponding to each stress segment before and after the working surface.

[0030] According to one embodiment of the present invention, step S4 includes: S41: performing shallow grouting reinforcement at the top plate of the high dynamic pressure tunnel; S42: performing surface reinforcement support at the high dynamic pressure tunnel; S43: performing deep drilling to advance pressure relief towards the bottom plate of the working face at the positions of the two lanes of the working face.

[0031] According to one embodiment of the present invention, the step S5 includes: S51: performing shallow grouting reinforcement in the medium dynamic pressure tunnel; S52: performing surface reinforcement support in the medium dynamic pressure tunnel.

[0032] According to one embodiment of the present application, the step S7 comprises: installing stress meters and surrounding rock deformation dynamic monitoring instruments in different dynamic pressure influence area roadways, monitoring the surrounding rock deformation and stress state of anchor rods and anchor cables, and monitoring the surrounding rock fracture range of the roadway after the influence of dynamic pressure by using the borehole peeping technology, and dynamically optimizing the roadway surrounding rock control scheme according to the monitoring results.

[0033] According to one embodiment of the present application, the grouting material is P.O42.5 ordinary portland cement slurry, and the water-cement ratio is 0.5:1-0.75:1.

[0034] According to one embodiment of the present application, the proportioning of the sprayed concrete material is cement:sand:stone:accelerating agent = 1:2:2:0.04, the water-cement ratio is 0.4-0.5:1, the sprayed concrete thickness is 100 mm, and the sprayed concrete strength is C20.

[0035] Compared with the prior art, the method has the advantages that:

[0036] (1) The method adopts a deep-shallow-surface surrounding rock partition differential control method, is aimed at multi-layer underlying multi-layer large roadways, effectively stabilizes the surrounding rock from multiple dimensions by combining deep advanced pressure relief, shallow grouting reinforcement and surface reinforcement support multiple measures, and overcomes the limitations of a single surrounding rock stability control method in a dynamic pressure environment.

[0037] (2) The method takes differential surrounding rock control measures for different dynamic pressure influence areas, considers the surrounding rock stress, crushing and floor damage of different partition roadways, differentially takes various surrounding rock control measures, and ensures that the surrounding rock stability of each region is controlled in a targeted manner.

[0038] (3) The method installs various monitoring devices in the surrounding rock of different partition roadways, monitors the surrounding rock control condition of the multi-layer underlying roadway under the influence of dynamic pressure in real time, thereby effectively testing the roadway surrounding rock control effect, dynamically optimizing the roadway surrounding rock control scheme according to the monitoring results, and improving the effect and reliability of the roadway surrounding rock control.

[0039] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 Flowchart of a method for controlling differences in surrounding rock zoning of multi-layered underlying roadways under the influence of dynamic pressure according to an embodiment of the present invention;

[0042] Figure 2 A schematic diagram of a mechanical model of stress distribution in a mining floor of a working face according to an embodiment of the present invention;

[0043] Figure 3 2. A model diagram of the stress increment coefficient and dynamic pressure influence zoning of the floor surrounding rock according to one embodiment of the present invention;

[0044] Figure 4 Schematic diagram of a shallow grouting reinforcement technology for a roadway according to one embodiment of the present invention;

[0045] Figure 5 Schematic diagram of a high dynamic pressure tunnel surface reinforcement and support technology according to one embodiment of the present invention;

[0046] Figure 6 Schematic diagram of a deep drilling pressure relief technology for mining floor according to one embodiment of the present invention;

[0047] Figure 7 Schematic diagram of the surface reinforcement and support technology for medium (low) dynamic pressure tunnels according to an embodiment of the present invention.

[0048] In the figure: 1-working face; 2-coal body; 21-stress concentration zone; 22-stress increase zone; 23-stress reduction zone; 3-goaf; 31-stress recovery zone; 4-original rock stress zone; 5-floor surrounding rock; 6-underlying tunnel; 7-high dynamic pressure influence zone; 71-high dynamic pressure tunnel; 8-medium dynamic pressure influence zone; 81-medium dynamic pressure tunnel; 9-low dynamic pressure influence zone; 91-low dynamic pressure tunnel; 10-grouting borehole; 101-grouting pump; 102-grouting slurry; 103-grouting hose; 11-anchor rod; 12-anchor cable; 13-auxiliary anchor cable; 14-pressure relief hole; 15-two tunnels on the working face. DETAILED DESCRIPTION

[0049] The following is a brief description of the specific embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts are also within the scope of protection of the present invention.

[0050] The following describes a method for controlling differences in surrounding rock zoning of a multi-layered underground roadway under the influence of dynamic pressure, as proposed in an embodiment of the present invention, with reference to the accompanying drawings.

[0051] Figure 1 Flowchart of a method for controlling differences in surrounding rock zoning in multi-layered underlying roadways under the influence of dynamic pressure according to an embodiment of the present invention.

[0052] like Figure 1 As shown, the method for controlling the difference in surrounding rock zoning of multi-layered underlying roadways under the influence of dynamic pressure according to an embodiment of the present invention includes the following steps:

[0053] S1: Establish a stress distribution mechanical model of the mining floor of the working face. Determine the width of the working face, the range of the stress concentration zone, and the range of the stress recovery zone based on the stress distribution mechanical model, on-site geological conditions, and the stress distribution characteristics of the surrounding rock of the mining area. Calculate the load distribution in the stress concentration zone and the stress recovery zone.

[0054] Specifically, in step S1, the stress distribution mechanical model of the mining floor of the working face is as follows: Figure 2 As shown in the figure, for the convenience of theoretical analysis, the model is appropriately simplified and assumed:

[0055] Coal seam mining causes stress redistribution in the rock formations around the mining space. One side of the coal body 2 is the goaf 3, and the other side of the coal body 2 is solid. The supporting pressure acting on the coal body 2 is approximately triangularly distributed. The front of the working face 1 is divided into a stress concentration zone 21 and an original rock stress zone 4, and the rear of the working face 1 is divided into a stress recovery zone 31 and an original rock stress zone 4. The boundary loads of the stress recovery zone 31 and the stress concentration zone 21 are both monotonically increasing or decreasing linear loads, and the load of the original rock stress zone 4 is a uniformly distributed load, and the original rock stress is set to γH. The coal body 2 in front of the working face and the surrounding rock 5 of the coal seam floor are regarded as elastic bodies.

[0056] Furthermore, the width of the working face 1 and the range of the stress concentration zone 21 in front of the working face are determined based on the on-site geological conditions and the stress distribution characteristics of the surrounding rock of the mining area. The range of the stress recovery zone 31 behind the working face is calculated based on the width of the working face 1 and the range of the stress concentration zone 21 in front of the working face, and the load distribution of the stress concentration zone 21 and the stress recovery zone 31 are obtained accordingly.

[0057] According to one embodiment of the present invention, the calculation formula of the stress recovery zone range is as follows:

[0058] L3=L2(K-1)-2L1

[0059] L3 is the range of stress recovery zone; L2 is the range of stress concentration zone; L1 is the width of working face; K is stress concentration coefficient;

[0060] The stress concentration zone comprises a stress increasing zone and a stress decreasing zone;

[0061] The load distribution calculation formula corresponding to the stress increasing zone is:

[0062]

[0063] L2 is the range of stress concentration zone; γ is the overburden density; H is the buried depth; 21

[0064] The load distribution calculation formula corresponding to the stress decreasing zone is:

[0065]

[0066] The load distribution calculation formula corresponding to the stress recovery zone is:

[0067]

[0068] It should be noted that the width L1 of the working face is directly obtained from the specific working face provided mining geological condition data. The width and length of each working face are determined before mining division, so they are directly obtained. The range L2 of the stress concentration zone can be obtained by field measurement. By arranging a borehole stress meter in the two roadways of the working face, the advanced abutment pressure distribution during the mining process of the working face is directly obtained, so the value of L2 can be obtained. Therefore, it can be considered that the value of L2 is obvious data obtained by field measurement. The range L 21 The range L of the stress increasing zone is obtained in the same way as the range L2 of the stress concentration zone, and can be obtained by field measurement. The stress concentration coefficient K, the overburden density γ and the buried depth H can be obtained according to the geological data and related data provided by the mining party, which will not be described here.

[0069] S2: calculate the stress state of the surrounding rock at different positions of the mining floor, and divide the floor surrounding rock according to the stress state to obtain a dynamic pressure high influence zone, a dynamic pressure medium influence zone and a dynamic pressure low influence zone.

[0070] According to one embodiment of the present application, in step S2, a point ε is taken on the x-axis of the stress distribution mechanics model, and the distance from the origin is ε. The load on the differential body is dq i i ​​dε, and regard it as a small concentrated force, then the horizontal and vertical distances from a certain position in the floor rock layer to dε are x-ε and y respectively. The stress state at different positions of the mining floor surrounding rock is calculated by the following formula:

[0071]

[0072] Among them, σ x is the horizontal stress; σ y is the vertical stress; τ χy is the shear stress; x and y are the horizontal and vertical coordinates of a certain position in the bottom rock layer; L is the stress segment corresponding to the front and back of the working surface; q L is the load corresponding to each stress segment before and after the working surface.

[0073] Specifically, the above calculation formula can be used to determine the stress values ​​of the floor surrounding rock 5 at different locations of the underlying tunnel 6. By comparing this value with the original rock stress, the stress increment coefficient (maximum value is a) at different locations of the floor surrounding rock 5 can be obtained. max ). According to the stress increment coefficients in different regions, we can get Figure 3 The stress increment coefficient and dynamic pressure influence zoning model of the bottom plate surrounding rock shown in the figure can divide the bottom plate surrounding rock 5 into three areas, where the stress increment coefficient variation range is [0.75a max ,a max ] is divided into a high dynamic pressure influence zone 7, and the stress increment coefficient variation range is [0.5a max ,0.75a max ] is divided into the dynamic pressure influence zone 8, and the stress increment coefficient variation range is [1,0.5a max ] is divided into a low dynamic pressure influence zone 9.

[0074] S3: Based on the zoning results of the floor surrounding rock, the underlying tunnels at different locations are divided into corresponding zones to obtain high dynamic pressure tunnels, medium dynamic pressure tunnels and low dynamic pressure tunnels.

[0075] Specifically, after the mining of the working face 1, the stress of the floor surrounding rock 5 is redistributed. The closer the underlying roadway 6 arranged below the working face 1 is to the floor of the working face 1, the greater the environmental stress field it is subjected to, and the higher the degree of surrounding rock crushing. According to the stress environment of the underlying roadway 6, the underlying roadway 6 at different locations can be divided into zones, among which, Figure 3 As shown, the high dynamic pressure influence zone 7 corresponds to the high dynamic pressure lane 71 , the medium dynamic pressure influence zone 8 corresponds to the medium dynamic pressure lane 81 , and the low dynamic pressure influence zone 9 corresponds to the low dynamic pressure lane 91 .

[0076] S4: For high dynamic pressure tunnels, in the early stage of mining work when the dynamic pressure of high dynamic pressure tunnels is affected, shallow tunnel grouting reinforcement, tunnel surface reinforcement support and deep advanced unloading of mining floor are used to control the stability of the surrounding rock of high dynamic pressure tunnels.

[0077] It should be noted that the deep portion refers to the lower portion of the working face floor and the upper area of ​​the underlying roadway, which is farther away from the underlying roadway. The shallow portion refers to the shallower portion of the upper portion of the underlying roadway roof, encompassing the boundary between the complete crushing zone and the crushing reduction zone of the underlying roadway. The surface portion refers to the surface of the underlying roadway, encompassing the active area of ​​support components such as anchor bolts (cables). The deep and shallow portions can be set based on specific working face parameters.

[0078] According to one embodiment of the present invention, step S4 includes:

[0079] S41: Shallow grouting reinforcement is carried out on the roof of the high dynamic pressure tunnel.

[0080] Specifically, the shallow grouting reinforcement technology of tunnels is as follows: Figure 4 As shown, grouting drilling 10 is carried out at the top plate position of the high dynamic pressure tunnel, the spacing between the drilling holes 10 is 4 to 5m, the grouting drilling holes 10 penetrate to the boundary between the broken surrounding rock area and the intact surrounding rock area, and the grouting pressure is ≥6Mpa; the grouting slurry 102 adopts P.O42.5 ordinary Portland cement slurry, which is injected into the grouting borehole 10 by the grouting pump 101 through the grouting hose 103. After the grouting is completed, the hole is sealed and 5-7 days of slurry solidification time is reserved.

[0081] S42: Carry out surface reinforcement support in high dynamic pressure tunnels.

[0082] Specifically, high dynamic pressure tunnel surface reinforcement support technology such as Figure 5As shown, specifically: on the basis of the original support, high preload anchor rods and anchor cables are used to strengthen the support; ① Top plate support: left-handed non-longitudinal reinforcement threaded steel anchor rods 11 are used, with a spacing of ≤1600mm, a row spacing of ≤1600mm, and a length of 2600mm; anchor cables 12 are arranged in the middle of a row of anchor rods 11, with a spacing of ≤1600mm, a row spacing of ≤1600mm, and the length of anchor cables 12 must ensure that the anchoring section of anchor cables 12 is within the complete surrounding rock area; ② Side support: left and right sides of the side support Anchor cables 13 are arranged in the middle, with spacing ≤1600mm. The length of the cables should ensure that the anchoring sections of the cables are within the intact surrounding rock area. ③ Bottom plate support: Anchor rods 11 are arranged at the bottom corners, with an angle of 30° to the horizontal, a spacing ≤1600mm, and a length of 2600mm. Anchor rods 11 are arranged at the bottom plate, perpendicular to the bottom plate, with spacing ≤1600mm, a spacing ≤1600mm, and a length of 2600mm. After the anchor rods, cables, and other support components are installed, the surface is sprayed with 100mm thick grout.

[0083] S43: Deep drilling is carried out on the working face floor in both lanes to relieve pressure in advance.

[0084] Specifically, deep drilling pressure relief technology in mining floor is as follows: Figure 6 As shown, specifically: pressure relief holes 14 are drilled obliquely downward toward the high dynamic pressure laneway 71 area at the positions of the two lanes 15 of the working face; the minimum aperture of the pressure relief holes 14 is 95 mm, the spacing between the pressure relief holes 14 cannot exceed 10 m, and the depth of the pressure relief holes 14 is the depth of the high dynamic pressure influence zone 7.

[0085] S5: For medium dynamic pressure tunnels, in the early stage of mining work when the dynamic pressure of the medium dynamic pressure tunnels is affected, the shallow grouting reinforcement of the tunnels and the tunnel surface reinforcement support technology are used to control the stability of the surrounding rock of the medium dynamic pressure tunnels.

[0086] According to one embodiment of the present invention, step S5 includes:

[0087] S51: Shallow grouting reinforcement is carried out in the medium dynamic pressure tunnel.

[0088] Specifically, the shallow grouting reinforcement technology of tunnels is as follows: Figure 4 As shown, grouting drilling 10 is carried out at the top plate position of the high dynamic pressure tunnel, the spacing between the drilling holes 10 is 4 to 5m, the grouting drilling holes 10 penetrate to the boundary between the broken surrounding rock area and the intact surrounding rock area, and the grouting pressure is ≥6Mpa; the grouting slurry 102 adopts P.O42.5 ordinary Portland cement slurry, which is injected into the grouting borehole 10 by the grouting pump 101 through the grouting hose 103. After the grouting is completed, the hole is sealed and 3-4 days of slurry solidification time is reserved.

[0089] S52: Carry out surface reinforcement support in the medium dynamic pressure tunnel.

[0090] Specifically, the surface reinforcement support technology of medium dynamic pressure tunnel is as follows: Figure 7 As shown, high preload anchors and anchor cables are used to reinforce the existing support. Specifically: ① Top plate support: Left-handed unreinforced threaded steel anchors 11 are used, with a spacing of ≤1600mm, a row spacing of ≤1600mm, and a length of 2600mm. They are equipped with steel belts and laid with metal mesh. Anchor cables 12 are arranged in the middle of a row of anchors 11, with a spacing of ≤1600mm, a row spacing of ≤1600mm, and a length that ensures that the anchoring section of the anchor cables 12 is within the intact surrounding rock area. ② Side support: A side anchor cable 13 is arranged in the middle of each of the left and right sides. The row spacing of the side anchor cables 13 is ≤1600mm, and the length is to ensure that the anchoring section of the side anchor cables 13 is within the intact surrounding rock area. After the installation of the anchor rods, anchor cables and other support components is completed, the surface is sprayed with 100mm of grouting thickness.

[0091] S6: For low dynamic pressure roadways, in the early stage of mining operations when the dynamic pressure of low dynamic pressure roadways is affected, the roadway surface reinforcement support technology is used to control the stability of the surrounding rock of the low dynamic pressure roadway;

[0092] Specifically, if Figure 7 As shown, low-dynamic-pressure tunnels utilize a combination of high-preload anchors and cables for reinforced support based on the existing support. Specifically: ① Roof support: Left-handed, unreinforced threaded steel anchors 11 are used, with spacing ≤1600mm, row spacing ≤1600mm, and a length of 2600mm. Anchor cables 12 are arranged in the middle of a row of anchors, with spacing ≤1600mm, row spacing ≤1600mm, and the length of anchor cables 12 must ensure that the anchoring section of anchor cables 12 is within the intact surrounding rock area. ② Side support: A side anchor cable 13 is arranged in the middle of each of the left and right sides, with a row spacing ≤1600mm and a length that ensures that the anchoring section of side anchor cables 13 is within the intact surrounding rock area. After the installation of support components such as anchors and cables, surface grouting is performed with a 100mm thickness.

[0093] S7: Real-time monitoring of the surrounding rock conditions of the underlying roadway under the influence of different dynamic pressures, and dynamic optimization of the surrounding rock control measures of the underlying roadway based on the monitoring results.

[0094] According to one embodiment of the present invention, step S7 includes: installing stress gauges and surrounding rock deformation dynamic monitoring instruments in tunnels in different dynamic pressure influence areas to monitor the deformation of the tunnel surrounding rock and the stress state of anchor rods and anchor cables, and using drilling peek technology to monitor the scope of tunnel surrounding rock rupture after the influence of dynamic pressure, and dynamically optimizing the tunnel surrounding rock control plan based on the monitoring results.

[0095] Specifically, anchor rods, anchor cable stress gauges, and surrounding rock deformation dynamic monitors can be installed in roadway areas affected by varying degrees of dynamic pressure. These can monitor the deformation of the roadway's surrounding rock, as well as the stress state of the anchor rods and cables used to reinforce the roadway. These data can be used to assess the roadway's stability. Furthermore, borehole peek technology—drilling holes in the rock formation and then observing the inside of the holes with peek equipment—can be used to monitor the extent of fracture in the roadway's surrounding rock after dynamic pressure has occurred, thereby assessing the fracture and deformation of the rock formation. Based on these monitoring results, the control scheme for the roadway's surrounding rock can be dynamically optimized, allowing adjustments and improvements to support design and construction methods based on real-time data to improve the stability and safety of the roadway.

[0096] According to one embodiment of the present invention, the grouting material is P.O42.5 ordinary Portland cement slurry with a water-cement ratio of 0.5:1 to 0.75:1.

[0097] According to one embodiment of the present invention, the spraying concrete material ratio of the spraying is cement: yellow sand: gravel: accelerator = 1:2:2:0.04, the water-cement ratio is 0.4-0.5:1, the spraying concrete thickness is 100mm, and the spraying concrete strength is C20.

[0098] In summary, according to the method for controlling the zoning differences of the surrounding rock of the multi-layered underlying tunnel under the influence of dynamic pressure in an embodiment of the present invention, a mechanical model of the stress distribution of the mining floor of the working face is constructed to calculate the load distribution of the mining stress concentration zone and the stress recovery zone; the stress state of the surrounding rock of the mining floor at different positions is calculated, and the surrounding rock of the floor is partitioned accordingly to obtain the high dynamic pressure influence zone, the medium dynamic pressure influence zone and the low dynamic pressure influence zone; according to the results of the floor surrounding rock zoning, the underlying tunnels at different positions are divided into corresponding zones to obtain the high dynamic pressure tunnel, the medium dynamic pressure tunnel and the low dynamic pressure tunnel. Low dynamic pressure roadway; for high dynamic pressure roadway, shallow grouting reinforcement, roadway surface reinforcement support and deep advanced unloading of mining floor are used to control the roadway surrounding rock stability; for medium dynamic pressure roadway, shallow grouting reinforcement and roadway surface reinforcement support are used to control the roadway surrounding rock stability; for low dynamic pressure roadway, roadway surface reinforcement support is used to control the roadway surrounding rock stability; finally, the surrounding rock conditions of the underlying roadway under different dynamic pressures are monitored in real time, and the surrounding rock control measures are dynamically optimized based on the monitoring results. Therefore, this method ensures that the surrounding rock stability of each area is effectively controlled by using multiple differentiated surrounding rock control measures of "deep-shallow-surface" for multi-layered underlying large roadways under the influence of dynamic pressure; and the surrounding rock control conditions of the multi-layered underlying roadways under the influence of dynamic pressure are monitored in real time, thereby effectively verifying the roadway surrounding rock control effect, and the roadway surrounding rock control scheme is dynamically optimized based on the monitoring results, improving the effectiveness and reliability of the roadway surrounding rock control.

[0099] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure, characterized in that: include: S1: establishing a stress distribution mechanical model of the mining floor of the working face, determining the width of the working face, the range of the stress concentration zone, and the range of the stress recovery zone based on the stress distribution mechanical model, on-site geological conditions, and stress distribution characteristics of the surrounding rock of the stope, and calculating the load distribution of the stress concentration zone and the stress recovery zone; S2: Calculate the stress state of the surrounding rock of the mining floor at different positions, and divide the surrounding rock of the mining floor into zones according to the stress state to obtain a high dynamic pressure influence zone, a medium dynamic pressure influence zone, and a low dynamic pressure influence zone; S3: Based on the zoning results of the floor surrounding rock, the underlying roadways at different locations are divided into corresponding zones to obtain high dynamic pressure roadways, medium dynamic pressure roadways, and low dynamic pressure roadways; S4: For the high dynamic pressure roadway, in the early stage of mining operation when the high dynamic pressure roadway is affected by the dynamic pressure, shallow grouting reinforcement of the roadway, roadway surface reinforcement support and deep advanced pressure relief of the mining floor are used to control the stability of the surrounding rock of the high dynamic pressure roadway; S5: For the medium dynamic pressure roadway, in the early stage of mining operation when the medium dynamic pressure roadway is affected by dynamic pressure, shallow grouting reinforcement and roadway surface reinforcement support technology are used to control the stability of the surrounding rock of the medium dynamic pressure roadway; S6: For the low dynamic pressure roadway, in the early stage of mining operation when the low dynamic pressure roadway is affected by dynamic pressure, the roadway surface reinforcement support technology is used to control the stability of the surrounding rock of the low dynamic pressure roadway; S7: real-time monitoring of surrounding rock conditions of the underlying roadway under the influence of different dynamic pressures, and dynamically optimizing surrounding rock control measures of the underlying roadway based on the monitoring results; The calculation formula of stress recovery zone range is as follows: in, is the range of the stress recovery zone; is the range of the stress concentration area; is the width of the working surface; is the stress concentration factor; The stress concentration area includes a stress increase area and a stress reduction area; The load distribution calculation formula corresponding to the stress increase area is: in, is the range of the stress-increased area; is the bulk density of the overlying rock; For burial depth; The load distribution calculation formula corresponding to the stress reduction area is: ； The load distribution calculation formula corresponding to the stress recovery zone is: 。 2. The method for controlling the difference in surrounding rock zoning of multi-layered underlying roadways under the influence of dynamic pressure according to claim 1 is characterized in that: In step S1, the stress distribution mechanical model of the mining floor of the working face is: coal seam mining causes redistribution of rock stress around the mining space, one side of the coal body is the goaf, and the other side of the coal body is a solid, and the supporting pressure acting on the coal body is approximately triangularly distributed; wherein, the front of the working face is divided into the stress concentration zone and the original rock stress zone, and the rear of the working face is divided into the stress recovery zone and the original rock stress zone; the boundary loads of the stress recovery zone and the stress concentration zone are both monotonically increasing or decreasing linear loads, and the load of the original rock stress zone is a uniformly distributed load; the coal body in front of the working face and the surrounding rock of the coal seam floor are regarded as elastic bodies.

3. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to claim 1 is characterized in that: In step S2, a point is taken on the x-axis of the stress distribution mechanics model. , let its distance from the origin be , take its differential , then the load on this differential body is , and regard it as a small concentrated force, then a certain position in the bottom rock layer The horizontal and vertical distances are and , the stress state of the surrounding rock at different positions of the mining floor is calculated by the following formula: in, is the horizontal stress; is the vertical stress; is the shear stress; 、 is the horizontal and vertical coordinates of a certain position in the basement rock layer; The stress segments corresponding to the front and rear of the working surface; is the load corresponding to each stress segment before and after the working surface.

4. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to claim 1 is characterized in that: The step S4 comprises: S41: performing shallow grouting reinforcement on the roof of the high dynamic pressure roadway; S42: performing surface reinforcement support at the high dynamic pressure roadway; S43: Deep drilling is carried out on the working face floor in both lanes to relieve pressure in advance.

5. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to claim 1 is characterized in that: The step S5 comprises: S51: performing shallow grouting reinforcement at the medium dynamic pressure roadway; S52: Perform surface reinforcement support in the medium dynamic pressure tunnel.

6. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to claim 1 is characterized in that: The step S7 comprises: Stress gauges and surrounding rock deformation dynamic monitoring instruments are installed in tunnels in different dynamic pressure influence areas to monitor the deformation of the tunnel surrounding rock and the stress state of anchor rods and cables. Drilling peek technology is used to monitor the scope of tunnel surrounding rock rupture after the influence of dynamic pressure. The tunnel surrounding rock control plan is dynamically optimized based on the monitoring results.

7. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to any one of claims 1 to 6, characterized in that: The grouting material is P.O42.5 ordinary Portland cement slurry with a water-cement ratio of 0.5:1 to 0.75:

1.

8. The method for controlling the difference in surrounding rock zoning of multi-layered underground tunnels under the influence of dynamic pressure according to any one of claims 1 to 6, characterized in that: The spraying concrete material ratio for shotcrete is cement: yellow sand: gravel: accelerator = 1:2:2:0.04, the water-cement ratio is 0.4~0.5:1, the spraying concrete thickness is 100 mm, and the spraying concrete strength is C20.

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