Pressure relief method for coal mine digging and anchoring working face

Abstract

The invention discloses a pressure relief method for a coal mine tunneling and anchoring working face, which belongs to the technical field of coal mining and comprises the following steps: constructing on a tunneling roadway head-on to form a head-on pressure relief hole; construction is conducted on the roadway side portion behind the head-on portion of the tunneling roadway, lateral coal body blast holes are formed, the lateral coal body blast holes are filled with explosives, and blasting pressure relief is conducted; the formation of the lateral coal blast holes comprises the following steps: setting the mass of blasting explosives, determining the influence radius of coal seam blasting and a coal lateral stress peak value on the basis of the mass of the blasting explosives, designing an arrangement scheme of the lateral coal blast holes, and performing construction; performing blasting pressure relief on the top of the tunneling roadway; according to the method, the difficult problem that the stress of the head-on area is difficult to effectively remove due to rapid tunneling is ingeniously solved, and the stress concentration phenomenon caused by untimely pressure relief of the rear coal seam and the roof is thoroughly eliminated.

Description

Technical Field

[0001] The invention relates to the technical field of coal mining, in particular to a pressure relief method for a coal mine anchoring working face. Background Art

[0002] The increasing demand for energy is driving coal mining towards a deeper and more efficient direction. The widespread use of integrated digging and anchoring machines in coal mine excavation has significantly improved production efficiency, but it has also brought many difficult problems. With the continuous increase in mining depth and the increasingly complex geological conditions, the frequency and intensity of rock burst are becoming more and more worrying. The rapid excavation of the integrated digging and anchoring machine causes a sharp accumulation of stress in the head area, and its unique equipment space greatly restricts the effective application of the existing large-diameter coal seam pressure relief hole technology. In addition, the excessively fast excavation speed makes it impossible for the coal seam and roof behind to adapt to the stress changes in time, resulting in a serious lag in pressure relief work and a prominent stress concentration problem. This not only seriously threatens the stability of the tunnel, but also lays a huge hidden danger for the safe production of coal mines.

[0003] A common means of decompression in the excavation working face is to decompress the coal seam through large-diameter drilling. This method is to discharge a large amount of coal powder in the borehole in the coal body, causing the coal body damage zone around the borehole to expand, thereby reducing the stress concentration of the coal rock body in a certain stress area around the borehole, and transferring the high stress to the deep part of the coal rock body to achieve decompression of the local coal body. Usually, according to the division range of the impact danger zone, 1 to 3 large-diameter boreholes in the coal seam are constructed at the head of the excavation tunnel, and the hole depth is generally between 30 and 40 meters. At the same time, in the tunnel side 20 meters behind the excavation head, large-diameter boreholes in the coal seam are constructed according to the division range of the impact danger zone, with a hole spacing of 1 to 3 meters, a hole depth of usually 15 to 25 meters, a borehole diameter of 150 mm, an angle between 0° and 3°, and arranged at a distance of 0.5 to 1.5 meters from the bottom plate of the tunnel.

[0004] Generally speaking, it takes 1 hour to construct a 20-meter large-diameter pressure relief hole. The impact hazard level of tunnels along the roadway is usually medium, and the anti-impact rules and national standards stipulate that pressure relief construction shall not be carried out simultaneously with coal cutting and tunnel support by tunnel boring machines. When using fast tunneling systems such as integrated digging and anchoring machines, it is necessary to ensure that the pressure relief measures for the head and two sides of the tunneling working face with impact hazards are in place. However, the average daily advance of the integrated digging and anchoring machine is about 16 meters (maximum 20 meters / day). For tunnels along the roadway, at least 8 20-meter large-diameter pressure relief holes need to be constructed every day to meet the pressure relief requirements, which takes 8 hours in total. The efficiency of pressure relief construction lags seriously behind the needs of tunneling production. At the same time, affected by the process of the integrated digging and anchoring machine, it is impossible to construct pressure relief holes at the head. In actual operation, there may be power outages due to equipment maintenance and water outages in the Yanfeng water pipeline, which further increases the difficulty and time cost of pressure relief construction. Therefore, it is necessary to optimize the traditional pressure relief method. Summary of the invention

[0005] In order to solve the problems of the prior art, the present invention provides a pressure relief method for a coal mine anchoring working face, comprising the following steps:

[0006] Construct the head-on construction in the excavation tunnel to form the head-on pressure relief hole;

[0007] Constructing the side of the tunnel behind the head of the tunnel to form a lateral coal body blasting hole, filling the lateral coal body blasting hole with explosives, and performing blasting to relieve pressure;

[0008] The formation of the lateral coal body blasting hole includes: setting the mass of blasting explosives, determining the impact radius of coal seam blasting and the peak value of coal body lateral stress based on the mass of blasting explosives, designing the arrangement plan of the lateral coal body blasting hole, and performing construction;

[0009] Blasting to relieve pressure is carried out at the top of the tunnel.

[0010] Furthermore, there are at least three head-on pressure relief holes.

[0011] Furthermore, the three head-on pressure relief holes are arranged in an isosceles triangle, wherein one head-on pressure relief hole is arranged in the middle of the tunnel, and the other two head-on pressure relief holes are respectively located on both sides below it, and form the waist of the isosceles triangle with the head-on pressure relief hole in the middle, and the distance between the two head-on pressure relief holes located below is 1.8-2.2m.

[0012] Furthermore, the diameter of the head-on pressure relief hole is 150 mm, and the depth of the drilled hole is 30-40 m.

[0013] Furthermore, the lateral coal body blasting holes are arranged in sequence according to the excavation speed, and the closest to the production side is arranged 12m behind the head.

[0014] Furthermore, the lateral coal blasting hole forms an angle of 20° with the side of the tunnel, an inclination of 0-3°, a diameter of 75mm, a depth of 50m, and is arranged at a distance of 0.5m to 1.5m from the bottom plate of the tunnel. The lateral coal blasting hole is constructed once every 30m of excavation, and the length of the pressure relief protection zone is not less than 5m.

[0015] Furthermore, the lateral coal blasting hole is filled with multiple explosive columns, with a total length of 6 meters, a diameter of 63 mm, a single explosive column length of 1.0 m, and a weight of 3.3 kg. After the filling of the explosive columns is completed, the media blasting hole is sealed, and the length of the sealed hole is 44 meters.

[0016] Furthermore, in order to weaken the impact of the overlying key layer on the tunnel excavation, blasting and breaking measures were taken in the middle of the tunnel roof 200m away from the front of the excavation. Multiple holes were drilled in the front direction, with a spacing of 20m between adjacent holes, a hole diameter of 75mm, a hole depth of 40m, a borehole inclination of 60°, and an azimuth of 270°.

[0017] Furthermore, the charge amount in the borehole is 40 kg, the charge section is 12 m long, and the remaining sections are sealed.

[0018] Beneficial effects of the present invention:

[0019] 1. It improves the production efficiency of coal mines. Through innovative pressure relief construction methods, it overcomes the space limitations of the excavator and anchor machine and the problems caused by rapid excavation, reduces construction stagnation and delays caused by stress problems, and thus significantly improves the excavation and mining efficiency of coal mines.

[0020] 2. It enhances the safety of operation, effectively solves the stress accumulation in the head area and the stress concentration in the rear area, reduces the risk of rock burst, provides a safer working environment for coal miners, and reduces the possibility of casualties and equipment damage.

[0021] 3. It optimizes resource utilization, realizes timely and sufficient pressure relief of the rear coal seam and roof, improves the recovery rate of coal resources, and reduces resource waste caused by stress damage.

[0022] 4. Reduced maintenance costs. The stable tunnel structure reduces the frequent repair and reinforcement of the tunnel, reducing maintenance costs and material consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the arrangement of the head-on pressure relief drilling holes for opening the door provided by the present invention;

[0024] Figure 2 A schematic diagram of the arrangement of lateral coal blasting holes provided by the present invention;

[0025] Figure 3 The present invention provides a cross-sectional schematic diagram of the arrangement of blasting top-breaking drilling holes. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] See also Figure 1-3The present invention provides a pressure relief method for a coal mine anchoring working face, comprising the following steps:

[0028] Before opening the door at the anchoring working face, pressure relief is carried out.

[0029] Three boreholes are constructed at the head of the excavation tunnel. The first borehole is arranged in the middle of the tunnel, and the other two are arranged in the shape of an isosceles triangle in the symmetrical tunnels. The spacing between the bases of the isosceles triangles is 2m, the diameter of the borehole is 150mm, and the depth of the borehole is 40m.

[0030] Step 2: Setting of lateral coal blasting holes during excavation stage.

[0031] The total length of the Sandvik MB670 bolter and miner is about 11.2 meters. In order to meet the requirements of the lag distance for both head pressure relief and side pressure relief, a lateral coal blasting hole was arranged on the production side 12 meters behind the head.

[0032] In the field test, 20 kg of water gel explosive was used for pressure relief blasting during coal seam blasting, and its effective impact radius was about 10 meters. According to the field drill cuttings method, the peak lateral stress of the coal body is usually located in the range of 6 to 10 meters from the roadway wall. In view of the fact that the anchoring length of the rock bolt of the impact rock mine wall is 2.8 meters, in order to minimize the deformation and damage to the surrounding rock of the wall anchoring and prevent excessive "overhang" of the roof, and considering that the maximum daily advance of the integrated drilling and anchoring machine along the air channel is about 20 meters, and in order to make the effective impact radius of the pressure relief blasting completely cover the stress peak area, while taking into account the maximum pressure relief effect achieved with the least on-site anti-impact engineering, the coal body blasting hole is designed to be at a 20° angle to the roadway wall, and the diameter of the coal body blasting hole is set to 75 mm, the inclination angle of the coal blasting hole is between 0 and 3°, the depth of the coal blasting hole is 50 meters (including 6 meters of charging length, using coal mine permitted water gel column, 63mm in diameter, 1.0m in length, 3.3kg in weight, 44 meters in sealing length, using quick-setting sealing material to seal the entire hole), the spacing is 20 meters, the coal blasting holes are arranged at a distance of 0.5 to 1.5 meters from the bottom plate of the tunnel (can be adjusted according to the actual situation on site), and construction is carried out every 20 meters. The drilling arrangement details are as follows Figure 1 shown.

[0033] Step 3: Blasting the top of the road head-on.

[0034] In the middle of the tunnel roof outside the pressure relief management station directly ahead of the excavation, blasting is carried out based on the results of on-site drilling and coring, and the drilling spacing is arranged based on the range of the pressure relief blasting effect.

[0035] Due to the use of the fast excavation system of the integrated excavator and anchor machine, the roof stress of the excavation face failed to be adjusted in a timely and effective manner, which led to the concentration of roof stress. At the same time, taking into account the regulatory requirements such as the single-shift limit on the excavation face, in order to reduce the impact of the overlying key layer on the tunnel excavation, blasting and breaking measures are implemented in the middle of the tunnel roof 200 meters (limited management station) directly opposite the excavation. Combined with the parameters of the on-site roof coring drilling, holes are opened in the head direction, with a drilling spacing of 20 meters, a hole diameter of 75 mm, a hole depth of 40 meters, an inclination of 60°, an azimuth of 270°, a charge of 40 kg, a charge section of 12 meters, and the remaining sections are sealed. The schematic diagram is as follows Figure 2 As shown. The relevant parameters can be reasonably optimized according to the actual situation on site to ensure the pressure relief effect. For example, in some similar excavation projects, if such blasting and breaking roof measures are not taken in time, serious problems such as roof sinking and support structure damage may occur. However, through reasonable planning and implementation, the safety and smooth progress of excavation work can be effectively guaranteed.

[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pressure relief method for a coal mine anchoring working face, characterized in that: The method comprises the following steps: Construct the head-on construction in the excavation tunnel to form the head-on pressure relief hole; Constructing the side of the tunnel behind the head of the tunnel to form a lateral coal body blasting hole, filling the lateral coal body blasting hole with explosives, and performing blasting to relieve pressure; The formation of the lateral coal body blasting hole includes: setting the mass of blasting explosives, determining the impact radius of coal seam blasting and the peak value of coal body lateral stress based on the mass of blasting explosives, designing the arrangement plan of the lateral coal body blasting hole, and performing construction; Blasting to relieve pressure is carried out at the top of the tunnel.

2. The pressure relief method for coal mine anchoring working face according to claim 1, characterized in that: The number of the head-on pressure relief holes is at least 3.

3. The pressure relief method for coal mine anchoring working face according to claim 2, characterized in that: The three head-on pressure relief holes are arranged in an isosceles triangle, one of which is arranged in the middle of the tunnel, and the other two are located on both sides below it, and form the waist of the isosceles triangle with the head-on pressure relief hole in the middle, and the distance between the two head-on pressure relief holes located below is 1.8-2.2m.

4. The pressure relief method for coal mine anchoring working face according to claim 1, characterized in that: The diameter of the head-on pressure relief hole is 150 mm, and the depth of the drilled hole is 30-40 m.

5. The pressure relief method for coal mine anchoring working face according to claim 1, characterized in that: The lateral coal body blasting holes are arranged in sequence according to the excavation speed, and the closest to the production side is arranged 12m behind the head.

6. The pressure relief method for coal mine anchoring working face according to claim 1, characterized in that: The lateral coal blasting hole forms an angle of 20° with the side of the tunnel, an inclination of 0-3°, a diameter of 75mm, a depth of 50m, and is arranged at a distance of 0.5m to 1.5m from the bottom plate of the tunnel. The lateral coal blasting hole is constructed once every 30m of excavation, and the length of the pressure relief protection zone is not less than 5m.

7. The pressure relief method for coal mine anchoring working face according to claim 6, characterized in that: The lateral coal blasting hole is filled with multiple explosive columns, with a total length of 6 meters, a diameter of 63 mm, a single explosive column length of 1.0 m, and a weight of 3.3 kg. After the filling of the explosive columns is completed, the media blasting hole is sealed, and the length of the sealed hole is 44 meters.

8. The pressure relief method for coal mine anchoring working face according to claim 1, characterized in that: In order to weaken the influence of the overlying key layer on the tunnel excavation, blasting and breaking measures were taken in the middle of the tunnel roof 200m away from the front of the excavation. Multiple holes were drilled in the front direction, with a spacing of 20m between adjacent holes, a hole diameter of 75mm, a hole depth of 40m, an inclination of 60°, and an azimuth of 270°.

9. The pressure relief method for coal mine anchoring working face according to claim 8, characterized in that: The charge amount in the borehole is 40 kg, the charge section is 12 m long, and the remaining sections are sealed.

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