Cross-fault cutting and rock mass sliding monitoring method

Abstract

The present invention discloses a method for monitoring cross-fault top cutting and roadway formation and rock mass sliding, which belongs to the field of cross-fault monitoring technology, including determining the type, azimuth, inclination, height difference and mechanical state of the surrounding rock through geological drilling, calculating the range, angle and arrangement of the working face and cross-fault top cutting influence area according to the measured parameters; calculating the range of the cross-fault support influence area based on the range of the cross-fault top cutting influence area, and encrypting the roadway top plate and two-side anchor cable support in the cross-fault support influence area according to the calculation result; performing concentrated energy blasting top cutting in the cross-fault top cutting influence area; installing a cross-fault Newton force monitoring system on the acute angle side top plate of the fault plane and the axial direction of the roadway; and evaluating the activation sliding trend of the fault plane under the influence of mining according to the mining status of the working face and the changes in Newton force monitoring data. The present invention adopts the above method, and realizes the top cutting and roadway formation in the fault area and the movement monitoring of the rock mass in the fault area by installing the Newton force monitoring system.

Description

Technical Field

[0001] The invention relates to the technical field of cross-fault monitoring, and in particular to a cross-fault top cutting lane forming and rock mass sliding monitoring method. Background Art

[0002] In the process of underground coal mining, the arrangement of longwall working faces for comprehensive mechanized mining has been widely used. In the traditional 121 method (one tunnel is required to mine one working face), the longwall fully mechanized mining working face includes two long-distance tunnels, the air intake tunnel and the return air tunnel, and the cut-eye tunnel where fully mechanized mining equipment is installed. Due to the complex underground geological structure types, various fault structures are often exposed during the excavation and mining process, so the tunnels and working faces cross the fault surface. The structural stress in the underground fault structure area is large and there is a large amount of hidden gas. Generally, it is necessary to detect the structural conditions in advance during the mining process to avoid hidden dangers such as rock spalling along the fault surface, hidden gas outburst, and high structural stress impact. The 110 method of cutting the top to the lane realizes the mode of excavating only one lane for one working face, reducing the tunnel excavation volume of a single working face by 50%, and reducing a series of safety hazards caused by the exposure of fault structures during tunnel excavation.

[0003] The 110 method of cutting the top and forming the roadway is one of the effective technologies to maintain the sustainable development of my country's coal resources. Under mining conditions with complex geological structures, the 110 method can preserve the original roadway by cutting the top and forming the roadway, avoiding the safety risk of roadway excavation under "black boxes" such as hidden fault structures. Therefore, it is crucial to ensure the high-quality implementation of the 110 method in fault structure areas. The 110 method includes two key technologies: effective and continuous pre-splitting and cutting the top and constant resistance support that adapts to large deformation. Since the retained roadway will experience the impact of mining on the working face, while achieving effective cutting and strengthening support in the fault area, the monitoring of fault activation should be increased. It is necessary to monitor the relative sliding trend of the rock mass on both sides of the fault plane to determine and warn whether the mining stress activates the fault and causes a violent sliding disaster of the rock mass along the fault plane, thereby affecting the effective support and safe retention of the roadway. Summary of the invention

[0004] The purpose of the present invention is to provide a cross-fault cutting and tunneling and rock mass sliding monitoring method, which can effectively realize the cutting and tunneling and the movement monitoring of the rock mass in the fault area.

[0005] To achieve the above-mentioned purpose, the present invention provides a method for monitoring cross-fault top cutting and rock mass sliding, the steps comprising:

[0006] S1. Determine the fault type, azimuth, inclination, height difference and mechanical state of the surrounding rock through geological drilling, and calculate the scope, angle and layout of the working face and cross-fault cutting top influence area based on the measured fault surface parameters, working face and tunnel parameters, equipment inclination and mining direction;

[0007] S2. Calculate the cross-fault support influence zone range based on the cross-fault cutting influence zone range, and increase the density of the tunnel roof and two-side anchor cable supports in the cross-fault support influence zone according to the calculation results;

[0008] S3, carrying out concentrated energy blasting and top cutting in the cross-fault top cutting influence area;

[0009] S4. Install a cross-fault Newton force monitoring system on the acute angle side roof between the fault plane and the axial direction of the tunnel;

[0010] S5. Based on the mining conditions of the working face and the changes in Newton force monitoring data, evaluate the activation slip trend of the fault surface under the influence of mining.

[0011] Preferably, the fault types in step S1 include normal faults and reverse faults.

[0012] Preferably, the range of the cross-fault cutting top impact zone in step S1 is calculated based on the cross-fault transition section angle, the cut-off rock layer depth and the fault surface parameters, including four categories: transition from low to high across normal faults, transition from high to low across normal faults, transition from low to high across reverse faults and transition from high to low across reverse faults. The calculation formulas for the four categories are:

[0013] From low to high transition across normal faults, the calculation formula is:

[0014]

[0015] From high to low transition across normal faults, the calculation formula is:

[0016]

[0017] From low to high transition across the reverse fault, the calculation formula is:

[0018]

[0019] From high to low transition across the reverse fault, the calculation formula is:

[0020]

[0021] Where L is the range of the cross-fault cutting impact zone, α is the elevation or depression angle of the working face across the fault, β is the fault dip, Δh is the fault drop, and h m is the thickness of the coal seam, h q is the thickness of the top rock layer.

[0022] Preferably, the expression for calculating the range of the cross-fault support influence zone in step S2 is:

[0023] L0=L+2l

[0024] Where L0 is the range of the cross-fault support influence area, and l is the stress concentration range of tunneling and mining.

[0025] Preferably, in step S2, the densification of the tunnel roof and anchor cables on both sides in the cross-fault support influence area includes: reinforcing the support of the tunnel roof and anchor cables on both sides at the fault outside the advance mining area of ​​the working face, and supplementing the roof with constant resistance large deformation anchor cables.

[0026] Preferably, in step S3, the depth of the blasthole drilled across the fault top cutting influence zone covers the main cut-off rock formations of the normal section on both sides of the fault plane, and the blasthole drilling depth reaches the line connecting the bottoms of the blastholes on both sides of the axial fault plane.

[0027] Preferably, the installation of a cross-fault Newton force monitoring system in step S4 includes: monitoring the inclined drilling of the borehole, with the fault plane obliquely intersected by the tunnel roof, and controlling the angle between the fault plane and the fault plane to be at a large acute angle, monitoring the vertical depth of the borehole to be greater than the top cutting depth and anchoring to a deep stable rock formation.

[0028] Preferably, in step S5, the data of the Newton force monitoring system is connected to the mine's underground network system and transmitted to the ground engineering machine in real time, and the fault activation slip is warned and controlled in time by observing and monitoring the changes in the Newton force curve and combining the working face mining situation.

[0029] Therefore, the present invention adopts the above-mentioned cross-fault cutting and tunneling and rock mass sliding monitoring method, which has the following beneficial effects:

[0030] (1) By calculating the roof cutting influence zone and support influence zone of the mining roadway when crossing various fault planes in different directions, and controlling the depth and density of the roof cutting in the roadway transition section, the smooth cutting of the roof in the cross-fault area and the continuity of the roadway cutting are ensured. The roof of the roadway transition section in the fault area is kept stable through the reinforcement support at the precise position.

[0031] (2) By arranging a Newtonian force monitoring system for rock slip on the fault surface of the cross-fault tunnel, we can achieve quantitative analysis of blasting top cutting and fault activation slip, as well as quantitative evaluation of the fault activation slip status under the influence of working face mining. By digitizing the potential stability risks of the cross-fault top cutting tunnel roof caused by blasting disturbance and working face mining disturbance, we can achieve early warning of the tunnel roof support in the cross-fault area based on Newtonian force monitoring.

[0032] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 is a flow chart of the method of an embodiment;

[0034] Figure 2The layout parameters of the transition section of the cross-fault tunnel and the layout of the blasting drilling holes under different fault types in the embodiment;

[0035] Figure 3 A diagram showing the arrangement of Newton force monitoring at the cross-fault plane of the tunnel under different fault types in Example 1;

[0036] Figure 4 A three-dimensional diagram of the layout of the transition section of the working face mining tunnel across the normal fault in Example 1;

[0037] Figure 5 It is a cross-sectional view of the working face mining roadway in Example 1, where the cut surface of the transition section across the normal fault passes through the fault plane;

[0038] Figure 6 This is a rendering of the top surface of the continuous cutting of the mining roadway across the normal fault in the working face in Example 1;

[0039] Figure 7 A three-dimensional diagram of the Newton force monitoring arrangement across the fault of the tunnel roof in Example 1;

[0040] Reference numerals

[0041] 1. Cut rock layer, 2. Fault surface, 3. Blast hole, 4. Normal section of tunnel, 5. Transition section of tunnel across fault, 6. Upper wall of fault, 7. Lower wall of fault, 8. Cut top surface, 9. Collapsed waste rock in goaf, 10. Newton force monitoring system, 11. Complete rock layer. DETAILED DESCRIPTION

[0042] Example

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0044] Reference Figure 1 A method for monitoring cross-fault cutting and rock mass sliding, comprising the following steps:

[0045] S1. Determine the type, azimuth, inclination, height difference and mechanical state of the surrounding rock through geological drilling. Calculate the scope, angle and layout of the working face and cross-fault cutting top influence area based on the measured fault surface parameters, working face and tunnel parameters, equipment inclination and mining direction. The cross-fault cutting top influence area is the cross-fault transition section of the tunnel.

[0046] Fault types include normal faults and reverse faults, such as Figure 2As shown, the layout parameters of the tunnel cross-fault transition section 5 and the blasting drilling layout under different fault types, where a is a low-to-high transition across a normal fault, b is a high-to-low transition across a normal fault, c is a low-to-high transition across a reverse fault, and d is a high-to-low transition across a reverse fault. The range of the cross-fault cutting top impact zone is determined by the tunnel cross-fault transition section angle, the cut-off rock layer depth and the fault surface parameters. The calculation method of the cross-fault cutting top impact zone under different fault types is different, including four categories: transition from low to high across a normal fault, transition from high to low across a normal fault, transition from low to high across a reverse fault and transition from high to low across a reverse fault. The calculation formulas for the four categories are:

[0047] From low to high transition across normal faults, the calculation formula is:

[0048]

[0049] From high to low transition across normal faults, the calculation formula is:

[0050]

[0051] From low to high transition across the reverse fault, the calculation formula is:

[0052]

[0053] From high to low transition across the reverse fault, the calculation formula is:

[0054]

[0055] Where L is the range of the cross-fault cutting impact zone, α is the elevation or depression angle of the working face across the fault, β is the fault dip, Δh is the fault drop, and h m is the thickness of the coal seam, h q is the thickness of the top rock layer.

[0056] S2. The cross-fault support influence area adds the excavation mining stress concentration area on both sides of this range. The cross-fault support influence area range is calculated based on the cross-fault cutting top influence area range. The calculation expression of the cross-fault support influence area range is:

[0057] L0=L+2l

[0058] Where L0 is the range of the cross-fault support influence area, and l is the stress concentration range of tunneling and mining.

[0059] According to the calculation results, the anchor cable support of the roadway roof and two sides in the cross-fault support influence area is intensified. Specifically, the roadway roof and two sides at the fault are reinforced outside the advanced mining area of ​​the working face, and the roof is supplemented with constant resistance large deformation anchor cable support.

[0060] S3, perform concentrated blasting and top cutting in the cross-fault top cutting influence zone. The cross-fault top cutting influence zone, i.e., the depth of the blasthole 3 drilled in the transition section 5 covers the main cut-off rock layer 1 of the normal section roadway 4 on both sides of the fault surface 2, and the blasthole 3 is drilled to the line connecting the bottoms of the blastholes 3 on both sides of the axial fault surface.

[0061] The deepest blast holes are generally distributed in oblique lines on the plane, connecting and covering the top of the cut rock layer 1 with a drop on both sides of the fault plane 2, and the density can be increased to 1 / 2 to 2 / 3 of the spacing between conventional blast holes.

[0062] S4. Install a cross-fault Newton force monitoring system 10 on the top plate at the acute angle between the fault plane 2 and the axial direction of the tunnel. The Newton force monitoring system 10 is a prior art and will not be described in detail here. When the tunnel crosses different types of faults, the Newton force monitoring system 10 is installed starting from the acute angle side of the fault plane, such as Figure 3 As shown, a is a tunnel crossing a normal fault, and b is a tunnel crossing a reverse fault. When the tunnel crosses a normal fault, the Newton force monitoring system 10 is set up from the top plate of the normal section of the tunnel as the starting point to cross the fault surface; when the tunnel crosses a reverse fault, the Newton force monitoring system 10 is set up from the top plate of the transition section of the tunnel as the starting point to cross the fault surface.

[0063] During drilling, the monitoring borehole is drilled at an angle, with the tunnel roof obliquely intersecting the fault plane, and the angle between the monitoring borehole and the fault plane is controlled at a large acute angle. The vertical depth of the monitoring borehole is greater than the top cutting depth and is anchored to a deep stable rock formation.

[0064] The angle between the Newton force monitoring system and the fault plane is maintained at 60 to 90 degrees. The system is anchored inside the intact rock layer 11 deep in the roof, and the vertical depth is greater than the depth of the cut-off rock layer 1.

[0065] S5. The data of the Newton force monitoring system is connected to the underground network system of the mine and transmitted to the ground engineering machine in real time. By observing and monitoring the changes in the Newton force curve and combining the mining situation of the working face, the activation and slip trend of the fault surface under the influence of mining is evaluated. When the Newton force drops suddenly, it is a precursor to slip. In the early warning period, high-strength anchor cables are reinforced and supported in time, and the roadway cross-fault section roof surrounding rock is warned and controlled during the mining influence period and the roadway retention reuse period.

[0066] Example 1

[0067] Taking the normal fault as an example, the transition from low to high across the normal fault, the dip angle β is 75°, the height difference Δh is 2m, the fault surface 2 is neat and has no broken zone; the coal seam thickness is 3m, the tunnel 4 height is 3m, and the cut roof rock layer 1 height is h q is 6m, the working face is from low to high along the cross-fault with α=10° elevation angle and α=10° depression angle, and s is the axial range distance of the tunnel cross-fault transition section 5. Figure 4As shown in the figure, it is a three-dimensional diagram of the layout of the transition section of the working face mining tunnel across the normal fault. The axial distance of the transition section 5 of the tunnel across the fault is calculated as: The impact area of ​​cross-fault cutting is

[0068]

[0069] The cross-fault support influence zone L0 is added with the excavation mining stress concentration zone range l on both sides of the cross-fault cutting top influence zone range, l = 5m, then the cross-fault support influence zone range L0 = L + 2l = 24.25m. During the initial support, the cross-fault support influence zone L0 = 24.25m is outside the advance mining zone range of the working face mining to reinforce the tunnel roof and the two side anchor cables at the fault, and the roof is supplemented with constant resistance large deformation anchor cable support to cope with the severe mining impact of the working face.

[0070] The cross-fault cutting top impact area is cut by concentrated energy blasting. Figure 5 As shown in FIG. 1 , it is a cross-sectional view of the top cutting surface 8 of the working face mining roadway across the normal fault transition section 5 passing through the fault plane 2. The deepest blasting holes 3 are generally distributed in oblique lines on the plane, connecting and covering the top of the cut rock layer 1 with a drop on both sides of the fault plane 2. The spacing of the top cutting holes 3 in the normal section 4 roadway is 500 mm. Within the cross-fault top cutting influence area range L of the roadway cross-fault transition section 5, the density of the top cutting holes 3 is increased to 300 mm to ensure the cutting of the main rock layer 1 in the cross-fault area and the continuity of the top cutting surfaces 8 on both sides of the fault plane 2. The effect diagram is shown in FIG. Figure 6 shown.

[0071] The Newton force monitoring system 10 is installed with the acute angle side of the fault plane 2 as the starting point. The Newton force monitoring system 10 is installed with the top plate of the normal section 4 of the tunnel as the starting point and along the large acute angle γ to cross the fault plane 2. Figure 7 As shown, the vertical depth of the monitoring borehole should be greater than 6m and anchored to the inside of the intact rock layer 11 deep in the roof. By observing and monitoring the changes in the Newton force curve and combining the mining situation of the working face, the activation sliding trend of the fault surface under the influence of mining is evaluated.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for monitoring cross-fault cutting and rock mass sliding, characterized in that the steps include: S1. Determine the type, azimuth, inclination, height difference and mechanical state of the surrounding rock through geological drilling, and calculate the scope, angle and layout of the working face and cross-fault cutting top influence area according to the measured parameters of the fault surface, working face and tunnel parameters, equipment inclination of the working face and tunnel, and the relationship between the mining direction; the types of faults include normal faults and reverse faults; The range of the cross-fault cutting top impact zone is calculated based on the cross-fault transition section angle, the cut-off rock layer depth and the fault surface parameters, including four categories: transition from low to high across normal faults, transition from high to low across normal faults, transition from low to high across reverse faults and transition from high to low across reverse faults. The calculation formulas for the four categories are: From low to high transition across normal faults, the calculation formula is: From high to low transition across normal faults, the calculation formula is: From low to high transition across the reverse fault, the calculation formula is: From high to low transition across the reverse fault, the calculation formula is: Where L is the range of the cross-fault cutting impact zone, α is the elevation or depression angle of the working face across the fault, β is the fault dip, Δh is the fault drop, and h m is the thickness of the coal seam, h q is the thickness of the cut-top rock layer; S2. Calculate the cross-fault support influence area based on the cross-fault cutting influence area. The expression is: L0=L+2l; In the formula, L0 is the range of cross-fault support influence area, l is the range of excavation mining stress concentration; According to the calculation results, the cross-fault support influence area roadway roof and two-side anchor cable support are intensified, including: outside the advanced mining area of ​​the working face, the roadway roof and two-side anchor cable are reinforced and supported at the fault, and the roof is supplemented with constant resistance large deformation anchor cable support; S3, carrying out concentrated energy blasting and top cutting in the cross-fault top cutting influence area; S4. Install a cross-fault Newton force monitoring system on the acute angle side roof between the fault plane and the axial direction of the tunnel; S5. Based on the mining conditions of the working face and the changes in Newton force monitoring data, evaluate the activation slip trend of the fault surface under the influence of mining.

2. The method for monitoring cross-fault top cutting and rock mass sliding according to claim 1 is characterized by: In step S3, the depth of the blasthole drilled across the fault top cutting influence area covers the main cut-off rock formations of the normal section on both sides of the fault plane, and the blasthole drilling depth reaches the line connecting the bottoms of the blastholes on both sides of the axial fault plane.

3. The method for monitoring cross-fault top cutting and rock mass sliding according to claim 2 is characterized in that: The installation of the cross-fault Newton force monitoring system in step S4 includes: monitoring the inclined drilling of the borehole, with the fault plane obliquely intersected by the tunnel roof, and controlling the angle between the fault plane and the fault plane to be at a large acute angle, monitoring the vertical depth of the borehole to be greater than the top cutting depth and anchoring to a deep stable rock formation.

4. The method for monitoring cross-fault top cutting and rock mass sliding according to claim 3 is characterized by: In step S5, the data of the Newton force monitoring system is connected to the underground network system of the mine and transmitted to the ground engineering machine in real time. By observing and monitoring the changes in the Newton force curve and combining the mining situation of the working face, early warning and timely control of fault activation slip are carried out.

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