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Tunnel rockburst grading prevention and control method using NPR material

A rockburst and tunnel technology, applied in the field of grading prevention and control of tunnel rockburst, can solve the problems of slow release, inability to achieve energy, accumulation, etc., and achieve the effect of improving the ability to allow compression deformation, reducing the probability of rockburst occurrence, and preventing induced rockburst.

Active Publication Date: 2021-10-12
HOHAI UNIV
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AI Technical Summary

Problems solved by technology

However, the above-mentioned support system lacks effective pressure relief measures for the surrounding rock of the tunnel. The energy absorbed by the bolt and / or the anchor cable is limited, and the slow release of energy cannot be realized, which may easily cause the accumulation of energy in the surrounding rock of the tunnel and lead to the occurrence of rockburst.
Therefore, there is an urgent need for an integrated tunnel rockburst prevention and control method that takes into account pressure relief, support and softening, so as to solve the problem of unsatisfactory prevention and control effects of existing technologies and achieve effective prevention and control of tunnel rockbursts

Method used

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  • Tunnel rockburst grading prevention and control method using NPR material
  • Tunnel rockburst grading prevention and control method using NPR material
  • Tunnel rockburst grading prevention and control method using NPR material

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Embodiment 1

[0044] (1) Determine the intensity level of the rockburst;

[0045] Step 1: Use hydraulic fracturing to measure the ground stress state of the proposed tunnel, mainly including the maximum horizontal stress (S H ), minimum horizontal stress (S h ) and vertical stress (S v ) and the direction of the maximum principal stress and the dominant direction. Step 2: Determine the angle between the direction of the maximum horizontal principal stress near the borehole and the direction of the tunnel axis, and calculate the angle α between the direction of the maximum horizontal principal stress and the direction of the normal stress on the side of the tunnel in the tunnel cross section. Step 3: According to the elastic mechanics formula, calculate the stress acting on the side of the tunnel, the specific formula is as follows:

[0046]

[0047]

[0048] σ θ =3σ h -σ H

[0049] Where: σ H is the tunnel axial stress, Mpa; σ θ is the maximum tangential stress of the tunnel,...

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Abstract

The invention discloses a tunnel rockburst grading prevention and control method using an NPR material. For a weak rockburst area, a prevention and control scheme of spraying concrete, drilling small-aperture pressure relief holes and installing NPR anchor rods and reinforcing meshes is adopted; for a medium rockburst area, a prevention and control scheme of spraying steel fiber concrete, drilling pressure relief holes with large and small apertures, installing NPR anchor rods / cables and reinforcing meshes, injecting water into anchor cable drill holes and drilling tunnel face pressure relief holes is adopted; and for a strong rockburst area, a prevention and control scheme of spraying NPR steel fiber concrete, drilling pressure relief holes with large and small apertures, laying a flexible buffer layer and a reinforcing mesh, installing NPR anchor rods / cables, erecting an NPR steel arch, injecting water into anchor cable drill holes, and drilling tunnel face pressure relief holes and tunnel face blast holes is adopted. Due to the existence of the large-aperture pressure relief holes and the small-aperture pressure relief holes, surrounding rock has a free surface in the tangential direction of a tunnel, so that tangential deformation can be generated under the action of pressure, and elastic strain energy is released; and the water is injected into the anchor cable drill holes to weaken the strength of the rock mass in the tunnel surrounding rock, and the occurrence probability of rock burst is reduced.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a tunnel rock burst prevention and control method using NPR materials. Background technique [0002] With the increasing demand for resources, energy and infrastructure, underground engineering in the fields of hydraulic engineering, mines, highways, railways, etc. is developing in depth. For example, the diversion tunnel of the Jinping II Hydropower Station has a maximum buried depth of 2525m, and the Witwatersrand gold mine in South Africa has been mined at a depth close to 5000m. The planned Sichuan-Tibet Railway contains 35 deep tunnels with a maximum buried depth of 2600m. With the continuous increase of underground engineering depth, engineering disasters are increasing day by day, and the most important problem is the rockburst disaster induced by high ground stress. Rockburst is a special phenomenon in underground engineering. It has the character...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21D11/10E21D20/00
CPCE21D11/105E21D20/003
Inventor 朱淳卫云波王锦国李云剑孟庆祥乐慧琳
Owner HOHAI UNIV
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