Underground cavern decompression structure based on artificial cavern building

Abstract

The utility model provides an underground cavern pressure reduction structure based on artificial cave building, which comprises a cavern, and small-size drill holes and large-size pressure reduction caves are arranged on the left side and the right side of the cavern at equal intervals from the near to the distant; and a geological steel pipe is placed in the small-size drill hole, consolidation grouting is conducted between the pipe wall of the geological steel pipe and the hole wall of the drill hole, and the hole is sealed. The device has the advantages that the stress concentration position is determined through numerical simulation analysis, and the small-size drill holes and the large-size decompression caves are sequentially arranged perpendicular to the cavern wall, so that the stress concentration degree is reduced, the stress peak value migrates to the surrounding rock in the deeper part, the stress distribution in the surrounding rock is more uniform, and the surrounding rock in the larger and deeper range participates in bearing; excessive supporting is avoided, and economic and safe operation of the underground cavern is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of surrounding rock stress bearing, in particular to an underground cavern decompression structure based on artificial caving. Background Art

[0002] During the excavation process, underground caverns will experience load-relief relaxation. Hard rocks may experience spalling, cracking, rockbursts, etc., and soft rocks may experience large deformations, which will be more significant under high stress conditions. Ensuring the stability of the surrounding rock of the cavern is the primary task.

[0003] The traditional underground engineering excavation and support design method emphasizes timely support, starting from improving the bearing capacity of the surrounding rock, and adopts shotcrete, anchors / cables and other means to resist the impact. The specification requires that the support depth of the anchor cable should exceed the calculated depth of the plastic zone, but the actual situation is that the rock mass at the far end of the plastic zone near the elastic zone still has a large bearing capacity, so this method may lead to over-support.

[0004] In order to ensure the stability of the surrounding rock of the underground cavern, in addition to improving the bearing capacity of the surrounding rock, it can also be achieved by reducing the stress level in the surrounding rock. Therefore, we need a decompression structure that can reduce the stress concentration level of the surrounding rock and migrate the stress to the depth of the surrounding rock, thereby mobilizing a larger range of surrounding rock to carry the load evenly. Utility Model Content

[0005] The utility model aims to provide an underground cavern decompression structure based on artificial caving, which can reduce the stress concentration level of surrounding rocks, migrate stress to the depth of surrounding rocks, and thus mobilize a wider range of surrounding rocks to evenly bear the load.

[0006] In order to achieve the above object, the utility model is implemented through the following technical solutions:

[0007] An underground cavern decompression structure based on artificial cavitation comprises a cavern, wherein small-sized boreholes and large-sized decompression caverns are arranged at equal intervals on the left and right sides of the cavern from near to far; a geological steel pipe is placed in the small-sized borehole, and consolidation grouting is performed between the wall of the geological steel pipe and the wall of the borehole and the hole is sealed.

[0008] Furthermore, the spacing between the small-sized boreholes is 4m, the borehole diameter is 133mm, and the diameter of the geological steel pipe is 127mm.

[0009] Furthermore, the inner diameter of the large-sized decompression cave is 1 m and the depth is 4 m.

[0010] Compared with the prior art, the utility model has the following advantages:

[0011] The utility model discloses an underground cavern decompression structure based on artificial cavitation. Through numerical simulation analysis, the position of stress concentration is determined, and small-sized drill holes and large-sized decompression caves are arranged in sequence perpendicular to the cave wall, so that the stress concentration degree is reduced, the stress peak value migrates to the deeper surrounding rock, the stress distribution inside the surrounding rock is more uniform, and the surrounding rock in a larger and deeper range participates in the load-bearing, which is conducive to avoiding excessive support and ensuring the economical and safe operation of the underground cavern. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a top view of the utility model.

[0013] Figure 2 It is a front view of the utility model.

[0014] Figure 3 It is a schematic diagram of stress change of the utility model.

[0015] Figure numerals: 1. cavern; 2. small-sized borehole; 3. large-sized decompression cave; 4. geological steel pipe. DETAILED DESCRIPTION

[0016] The embodiments of the present utility model are described in further detail below in conjunction with the accompanying drawings.

[0017] like Figure 1 , 2 As shown, an underground cavern decompression structure based on artificial cavitation includes a cavern 1, and small-sized boreholes 2 and large-sized decompression caverns 3 are arranged at equal intervals on the left and right sides of the cavern 1 from near to far; a geological steel pipe 4 is placed in the small-sized borehole 2, and consolidation grouting is performed between the wall of the geological steel pipe 4 and the wall of the borehole 2 and the hole is sealed.

[0018] First, determine the location of cavern 1. According to the ground stress conditions and the physical and mechanical parameters of the surrounding rock in the area where the underground cavern is located, combined with the excavation size of cavern 1, a numerical simulation of the underground cavern excavation process is carried out to determine the location of the surrounding rock stress concentration area caused by excavation, which is the predetermined location of cavern 1. In this embodiment, the excavation cross-section of cavern 1 is circular, the first principal stress direction of the area is vertical, the second principal stress direction is along the cave axis, and the third principal stress direction is horizontal. Therefore, the stress concentration area is located on the left and right sides of cavern 1.

[0019] Secondly, arrange small-sized boreholes 2. The spacing between the small-sized boreholes 2 is 4m, and the borehole 2 has a diameter of 133mm. The drilling 2 operation is carried out by a mechanical water jet, and a high-low pressure conversion joint is used to connect the drill bit and drill rod of the selected size, start the pump station and the drilling rig, and start the drilling operation. The borehole 2 is perpendicular to the cave wall and passes through the predetermined cavern 1. According to the equipment function, the drill rod diameter is 89mm, the drill bit diameter (i.e., the borehole diameter) is 133mm, and the boreholes 2 are arranged in a row along the axial direction of the cavern, and the spacing between the boreholes 2 is set to 4 meters.

[0020] Next, a large-sized decompression cave 3 is arranged. The large-sized decompression cave 3 is connected to the small-sized borehole 2, and the inner diameter of the large-sized decompression cave 3 is 1m and the depth is 4m. The cave making operation is still carried out by mechanical water jet, and an automatic opening and closing mechanical hole expansion device is used to connect the drill bit and drill rod of the selected size. When the small-sized borehole 2 is drilled to the predetermined position, the advancement is stopped, the knife arm is opened, and the knife arm diameter is 1 meter. Continue to slowly advance 4 meters until the cave making operation is completed.

[0021] Finally, the geological steel pipe 4 is placed. In order to prevent the small-sized borehole 2 from damaging the integrity and stability of the surrounding rock, after the hole making operation is completed, a geological steel pipe 4 with a diameter of 127 mm is placed in the borehole 2, and consolidation grouting is performed between the borehole 2 and the pipe wall, and then the hole is sealed.

[0022] like Figure 3 As shown, with the horizontal axis representing the depth of surrounding rock and the vertical axis representing the stress magnitude, the stress curve shifts to the right as a whole, and the highest point of the curve decreases, indicating that the stress concentration degree decreases, the stress peak migrates to the deeper surrounding rock, the stress distribution inside the surrounding rock becomes more uniform, and a larger and deeper range of surrounding rock participates in the load-bearing.

[0023] The above is only a preferred embodiment of the present invention. It should be pointed out that ordinary technicians in this technical field can make several improvements and modifications without departing from the concept of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. An underground cavern decompression structure based on artificial caving, comprising a cavern, characterized in that: Small-sized boreholes and large-sized decompression caves are arranged at equal intervals on the left and right sides of the cavern from near to far; geological steel pipes are placed in the small-sized boreholes, and consolidation grouting is performed between the walls of the geological steel pipes and the walls of the boreholes and the holes are sealed.

2. The underground cave decompression structure based on artificial caving according to claim 1, characterized in that: The spacing between the small-sized boreholes is 4m, the borehole diameter is 133mm, and the diameter of the geological steel pipe is 127mm.

3. The underground cave decompression structure based on artificial caving according to claim 2, characterized in that: The large-sized decompression cave has an inner diameter of 1 m and a depth of 4 m.

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