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A classification method of tunnel rockburst prevention using npr materials

A rockburst and tunnel technology, which is applied in the field of tunnel rockburst classification prevention and control, can solve the problems of unrealized energy, slow release, accumulation, etc., and achieve the effects of reducing the probability of rockburst occurrence, improving the yielding deformation capacity, and preventing the induced rockburst

Active Publication Date: 2022-08-02
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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  • A classification method of tunnel rockburst prevention using npr materials
  • A classification method of tunnel rockburst prevention using npr materials
  • A classification method of tunnel rockburst prevention using npr materials

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Experimental program
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Embodiment 1

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

[0045] Step 1: Use the hydraulic fracturing method to measure the in-situ stress state of the proposed tunnel, mainly including the maximum horizontal stress (S H ), the minimum horizontal stress (S h ) and vertical stress (S v ) and the direction of 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 sidewall of the tunnel in the tunnel cross-section. Step 3: Calculate the stress acting on the sidewall of the tunnel according to the elastic mechanics formula. The specific formula is as follows:

[0046]

[0047]

[0048] σ θ =3σ h -σ H

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

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Abstract

The invention discloses a classification prevention method of tunnel rock burst using NPR material. For weak rockburst areas, the prevention and control plan of spraying concrete, drilling small-diameter pressure relief holes, and installing NPR bolts and steel meshes is adopted; NPR anchor rod / cable and steel mesh, water injection into the anchor cable hole, and drilling of pressure relief holes on the face; Prevention plan for laying flexible buffer layer and steel mesh, installing NPR anchor rods / cables, erecting NPR steel arches, injecting water into the anchor cable holes, drilling pressure relief holes on the face of the face and blasting holes on the face of the face; The existence of the pressure hole makes the surrounding rock have a free surface along the tangential direction of the tunnel, so that the tangential deformation can be generated under the action of pressure and the elastic strain energy can be released. Water injection into the anchor cable hole weakens the strength of the rock mass inside the surrounding rock of the tunnel and reduces the probability of rockburst.

Description

technical field [0001] The invention belongs to the technical field of tunnel construction, and in particular relates to a classification prevention method for tunnel rock burst using NPR materials. Background technique [0002] With the increasing demand for resources, energy and infrastructure, underground engineering in the fields of hydraulics, mines, highways, railways and other fields are all developing in depth. For example, the diversion tunnel of Jinping II Hydropower Station has a maximum buried depth of 2,525m, and the Witwatersrand gold mine in South Africa has a depth of nearly 5,000m. With the continuous increase of underground engineering depth, engineering disasters are increasing day by day, among which the most important problem is the rockburst disaster induced by high ground stress. Rock burst is a special phenomenon in underground engineering. It is characterized by the sudden and violent ejection, throwing and ejection of surrounding rock into the exca...

Claims

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Application Information

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Patent Type & Authority Patents(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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