CN108035742B - A method of active and passive harmonious support for extremely weak coal seam roadway - Google Patents

Abstract

The present invention is an active and passive harmonious support method for roadways in extremely soft coal seams. It discloses an advanced self-drilling glass fiber reinforced plastic grouting anchor rod to strengthen roadsides and reinforced roofs to control the surrounding rock control technology of mining roadways in extremely soft coal seams, including the following steps: Arrange externally tied self-drilling glass fiber reinforced plastic anchor rods at the contour line of the front roadway section of the excavation working face in advance, and determine the length, spacing and grouting parameters of the anchor rods according to the softness of the two sides of the roadway coal; After installing the self-drilling FRP bolt, you can install the grout stopper, connect the double-liquid pneumatic grouting pump, and start grouting; the grouting time should be fast first and then slow, and the grouting pressure can reach a given value to end; After solidification, the supporting plate can be installed, and the pre-tightening force can be applied; continue to excavate for several cycles, install high-strength anchor rods and anchor cables on the roof, and ensure that the installation and coordination of metal mesh, steel ladder and other surface protection components are good.

Description

A method of active and passive harmonious support for extremely weak coal seam roadway

technical field

The invention relates to a surrounding rock control technology of an extremely weak coal seam roadway, which belongs to the field of geotechnical support engineering, and in particular relates to a mine pressure control technology for backing the roadway surrounding rock to reinforce the roof and strengthen the two sides of the underground mining engineering.

Background technique

In Pingyu Coalfield, Xinmi Coalfield, and Yanshi-Longmen Coalfield in central and western Henan, the coal seam is subjected to strong geological tectonic action, its original structure is destroyed, and its integrity is poor. The coal seam is a mylonitic fragmentation medium with a Platts coefficient of 0.15-0.25 between. The mining roadways arranged in extremely soft coal seams are mostly passively supported by I-steel trapezoidal metal brackets. During the service period, they need to be renovated 3-4 times, which seriously affects the normal mining of the working face and consumes a lot of manpower, material and financial resources. Therefore, it is particularly urgent to improve the self-bearing capacity and support status of the surrounding rock of the extremely soft coal seam mining roadway.

At present, the roadway support methods for extremely soft coal seam recovery include: strong roof reinforcement method, two sides pressure relief + grouting strengthening method; strong roof reinforcement method adopts high-strength anchor rod-anchor cable to strengthen the roof support, and two sides adopt small spacing The I-beam paired shed is filled with snakeskin bags for coal racks; however, the on-site mine pressure observation shows that with the deformation of the two sides, the bending deformation of the bracket is serious, and the actual span of the roof increases with the deformation of the two sides. The span of the roadway and the supporting pressure of the two sides of the roadway are increased, and the two promote each other, resulting in the deterioration of the surrounding rock condition of the roadway. Two-side pressure relief + grouting strengthening method, using large-diameter pressure relief drilling to absorb the deformation of the surrounding rock, transfer high stress to the deep surrounding rock, and then carry out grouting reinforcement on the surrounding rock within a certain range of the lagging pressure relief hole to improve its self-bearing capacity However, the pressure relief drilling further expands the scope of the roadway rupture zone, which will cause deformation and damage to the roadway support before the two sides of the grouting. Therefore, it is difficult for the above method to achieve a better supporting effect for the control of extremely soft roadway surrounding rock.

Contents of the invention

Aiming at the problems of poor anchoring effect of the two sides of the mining roadway in extremely soft coal seams, serious deformation of the metal support, poor grouting effect, and many renovation times, the present invention proposes an advanced self-drilling glass fiber reinforced plastic grouting bolt to strengthen the roadside and strengthen the roof to control extreme softness The coal seam mining roadway surrounding rock control technology aims to solve the problem of anchorage of the two sides of the extremely soft coal seam mining roadway, realize the bearing problem of the extremely soft coal side, reduce the number of renovations, reduce the support cost, and achieve the purpose of safe use of the mining roadway during service.

In order to achieve the above object, the present invention is based on the advanced self-drilling glass fiber reinforced plastic grouting anchor bolt strengthening roadside and strengthening roof control technology, and the technical solution it adopts is an active and passive harmonious support method for extremely weak coal seam roadway, including the following steps:

Step 1: Arrange advanced self-drilling FRP bolts along the direction of excavation in the advanced section of the excavation head of the extremely weak coal seam recovery roadway; the advanced self-drilling FRP bolts include hollow FRP bolts, and the two ends of the hollow FRP bolts are set with internal thread,

Hollow fiberglass anchor rods are drilled with three flower-shaped slurry outlet holes. One end of the hollow fiberglass anchor rods is threaded with a hexagonal prism drive end, and the other end is threaded with a drill bit; the interior of the hexagonal prism drive end is a hollow threaded hole. There is a ring-shaped boss, and the outer surface of the ring-shaped boss is provided with external threads. The external thread of the ring-shaped boss matches the internal thread of the hollow glass fiber reinforced plastic anchor rod, and the driving end of the hexagonal column passes through the ring-shaped boss. Threaded connection with hollow fiberglass anchor rod;

Step 2: Drive the driving end of the hexagonal prism on the self-drilling FRP anchor with a rock bolt rig and drill to a given depth; if it needs to be lengthened, remove the driving end of the hexagonal prism and connect another hollow FRP anchor with a connecting sleeve. The other end of the other hollow FRP bolt is installed with the hexagonal driving end, and then continues to drill to a given depth;

Step 3, install the grout stopper, connect the grouting pump, inject the inorganic double-liquid grouting material into the advanced self-drilling FRP anchor rod through the hollow threaded hole at the driving end of the hexagonal prism, stop the grouting after reaching a given pressure, and install it after the grout solidifies Support plate, drive nut, apply pre-tightening force;

Step 4: install high-strength prestressed anchors on the roof; install U-shaped steel brackets at a certain distance on the lagging excavation face, and seal the two sides of the roadway with metal mesh and woven bags;

Step five, install the anchor cable through the U-shaped steel bracket, and the anchor cable lock acts on the U-shaped steel bracket.

Preferably, the included angle between the advanced self-drilling FRP bolt and the driving direction of the roadway is 30°.

Preferably, the drill bit is made of cast iron.

Preferably, the U-shaped steel support is installed 10-15m behind the excavation face to ensure parallel operation.

Preferably, the U-shaped steel bracket adopts a three-core arched U-shaped steel bracket, and the anchor cable passes through the U-shaped steel bracket to realize active and passive harmonious support.

The beneficial results of the present invention are: the present invention realizes the problem of the collapse of the anchor hole of the extremely soft coal body in advance, and at the same time improves the self-bearing capacity of the extremely soft coal body; The arched U-shaped steel bracket and the anchor cable through the frame improve the support resistance and realize the harmonious support of active-passive support. The present invention is based on advanced anchoring and grouting reinforcement, and improves the self-bearing capacity of the two gangs, which overcomes the damage of the soft coal body after the excavation of the roadway, the poor anchoring effect, the lack of hole collapse when installing the anchor rod and the grouting pipe, and the working face mining It is no longer necessary to dismantle the metal anchor rod, reducing the loss of the shearer pick; this technology can reduce the number of roadway renovations and reduce support costs.

Description of drawings

Figure 1 is a top view of the layout of advanced self-drilling FRP bolts;

Figure 2 is a side view of the advanced self-drilling FRP anchor arrangement;

Figure 3 is a front view of the advanced self-drilling FRP bolt arrangement;

Figure 4 is a structural diagram of the advanced self-drilling FRP bolt;

Figure 5 is a structural diagram of the driving end of the hexagonal prism of the advanced self-drilling FRP anchor;

Figure 6 is a section view of the active and passive support of the extremely weak coal seam roadway;

Fig. 7 is a schematic diagram of the cross-sectional structure of the driving end of the hexagonal prism of the advanced self-drilling FRP bolt.

In the figure: 1 is the tunneling direction; 2 is the coal body; 3 is the advanced self-drilling FRP bolt; 4 is the roadway; 5 is the grout hole; 6 is the grout stopper; Hole; 10 is the anchor rod connecting sleeve; 11 is the hollow fiberglass anchor rod; 12 is the self-drilling bit; 13 is the anchor cable; 14 is the roof high-strength prestressed anchor rod; 15 is the anchor cable sling; 18 is a nut; 19 is a slurry plug; 20 is an annular boss; 21 is a supporting plate.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and examples.

Example 1

As shown in Figure 1-7, an active and passive harmonious support method for extremely weak coal seam roadway includes the following steps:

Step 1: Arrange advanced self-drilling FRP bolts 3 along the direction of excavation in the advanced section of the tunneling head of the recovery roadway in extremely weak coal seams. The angle between the advanced self-drilling FRP bolts and the tunneling direction is 30°; The drill type FRP bolt 3 includes a hollow FRP bolt 11, the two ends of the hollow FRP bolt 11 are provided with internal threads, the hollow FRP bolt 11 is drilled with three flower-shaped slurry outlet holes 5, and one end of the hollow FRP bolt 11 is threaded. There is a hexagonal prism driving end 8, and the other end is threadedly connected with a self-drilling bit 12; there is a hollow threaded hole 9 inside the hexagonal prism driving end 8 (which can function as a grouting joint), and one end of the hexagonal prism driving end 8 is provided with An annular boss 20, the outer surface of the annular boss 20 is provided with an external thread, the external thread of the annular boss 20 matches the internal thread of the hollow fiberglass anchor rod 11, and the hexagonal prism driving end 8 passes through the ring Shaped boss 20 is threadedly connected with hollow fiberglass anchor rod 11;

Step 2: Drive the hexagonal prism driving end 8 on the self-drilling FRP anchor with a rock bolter (pneumatic rocker rig) and drill to a given depth; Rod connecting sleeve 10 (the connecting sleeve and the hollow FRP bolt are threaded) connected to another hollow FRP bolt, and the other end of the other hollow FRP bolt is installed with a hexagonal driving end, and then continues to drill to a given depth;

Step 3, install the grout stopper 6, connect the grouting pump, inject the inorganic double-liquid grouting material into the advanced self-drilling FRP anchor rod through the hollow threaded hole 9 at the driving end of the hexagonal prism, stop the grouting after reaching a given pressure, and the grout solidifies Install supporting plate 21, drive nut 18 afterward, apply pretightening force;

Step 4, install the high-strength prestressed anchor rod 14 on the roadway roof following the excavation working face; install the U-shaped steel bracket 16 on the lagging excavation working face 10-15m, and seal the two sides of the roadway with metal mesh and woven bags;

Step 5, install the anchor cable 13 through the U-shaped steel bracket 16 (the U-shaped steel metal bracket column leg and the spandrel are drilled, the anchor cable passes through the U-shaped steel bracket and is installed in the coal body after grouting reinforcement, and the anchor rod- Harmonious support of U-shaped steel bracket), the anchor cable lock 15 acts on the U-shaped steel bracket 16 to realize active and passive harmonious support; the section of the U-shaped steel bracket 17 is a three-centered arch, and the anchor cable 13 passes through the U-shaped steel; metal mesh Place behind the U-shaped steel support 17 with woven bag 17, fill in gangue or crushed coal, the back is tight and the back is solid.

This embodiment has realized the collapse of the anchor hole of the extremely soft coal body ahead of time, and at the same time improved the self-bearing capacity of the extremely soft coal body; strengthened the roof support, and reduced the effect on the two side coal bodies of the roadway; the three-core arched U-shaped steel bracket and The threaded anchor cable improves its support resistance, realizes the harmonious support of active-passive support, and reduces the number of repairs.

The present invention is not limited to the description of this embodiment, and any modification, equivalent replacement and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (5)

1. An active and passive harmonious support method for an extremely weak coal seam roadway, characterized in that it comprises the following steps: Step 1: Arrange advanced self-drilling FRP bolts along the direction of excavation in the advanced section of the excavation head of the extremely weak coal seam recovery roadway; the advanced self-drilling FRP bolts include hollow FRP bolts, and the two ends of the hollow FRP bolts are set with internal thread, Hollow fiberglass anchor rods are drilled with three flower-shaped slurry outlet holes. One end of the hollow fiberglass anchor rods is threaded with a hexagonal prism drive end, and the other end is threaded with a drill bit; the interior of the hexagonal prism drive end is a hollow threaded hole. There is a ring-shaped boss, and the outer surface of the ring-shaped boss is provided with external threads. The external thread of the ring-shaped boss matches the internal thread of the hollow glass fiber reinforced plastic anchor rod, and the driving end of the hexagonal column passes through the ring-shaped boss. Threaded connection with hollow fiberglass anchor rod; Step 2: Drive the driving end of the hexagonal prism on the self-drilling FRP anchor with a rock bolt rig and drill to a given depth; if it needs to be lengthened, remove the driving end of the hexagonal prism and connect another hollow FRP anchor with a connecting sleeve. The other end of the other hollow FRP bolt is installed with the hexagonal driving end, and then continues to drill to a given depth; Step 3, install the grout stopper, connect the grouting pump, inject the inorganic double-liquid grouting material into the advanced self-drilling FRP anchor rod through the hollow threaded hole at the driving end of the hexagonal prism, stop the grouting after reaching a given pressure, install the supporting plate, drive nut, apply preload; Step 4: install high-strength prestressed anchors on the roof; install U-shaped steel brackets at a certain distance on the lagging excavation face, and seal the two sides of the roadway with metal mesh and woven bags; Step five, install the anchor cable through the U-shaped steel bracket, and the anchor cable lock acts on the U-shaped steel bracket. 2. The active and passive harmonious support method for roadways in extremely weak coal seams according to claim 1, characterized in that: the included angle between the advanced self-drilling glass fiber reinforced plastic bolt and the driving direction of the roadway is 30°. 3. The active and passive harmonious support method for roadways in extremely weak coal seams according to claim 1, characterized in that: the drill bit is made of cast iron. 4. The active and passive harmonious support method for roadways in extremely weak coal seams according to claim 1, characterized in that: the U-shaped steel support is installed 10-15m behind the excavation face to ensure parallel operation. 5. The active and passive harmonious support method for extremely weak coal seam roadway as claimed in claim 1, characterized in that: the U-shaped steel support adopts a three-core arched U-shaped steel support, and the anchor cable passes through the U-shaped steel support to realize active and passive harmonious support .

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