CN109057813B

CN109057813B - Method for preventing and treating rock burst of shaft by using high-pressure water jet

Info

Publication number: CN109057813B
Application number: CN201810743750.6A
Authority: CN
Inventors: 梁伟章; 赵国彦; 刘雷磊; 吴浩; 陈英
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2018-07-09
Filing date: 2018-07-09
Publication date: 2021-04-20
Anticipated expiration: 2038-07-09
Also published as: CN109057813A

Abstract

The invention provides a method for preventing and treating rock burst of a shaft by using high-pressure water jet, which comprises the following steps: (S1) uniformly drilling more than 3 advanced pressure relief boreholes in the borehole wall; (S2) putting the high-pressure water jet pipe and the spray head into the drill hole, and spraying water beams at the bottom of the drill hole through the spray head to break rocks to form a perforation; (S3) continuously rotating the high-pressure water jet pipe, adjusting the jet direction of the spray head, obtaining a plurality of perforation holes with the same depth and positioned on the same plane, and forming a circular cutting groove with the spray head as the center of circle; (S4) repeating (S2) - (S3), forming circular cutting grooves at the bottoms of the drill holes respectively, enabling every two adjacent circular cutting grooves to be intersected with each other due to the perforation depth and the direction corresponding to each circular cutting groove, and forming a communicated annular shaft crushing zone outside the well wall, so that advanced continuous pressure relief is achieved, surrounding rock is softened by high-pressure water through rock mass cracks, and the purpose of efficiently preventing and treating rock burst is achieved.

Description

Method for preventing and treating rock burst of shaft by using high-pressure water jet

Technical Field

The invention belongs to the technical field of shaft tunneling engineering, and particularly relates to a method for preventing shaft rock burst by using high-pressure water jet, which is particularly suitable for disaster control of a high rock burst risk area in mine shaft tunneling.

Background

Deep shaft surrounding rock is in an extreme geomechanical environment with three-high-disturbance, the probability and frequency of deep engineering disasters such as high-strength rock burst and the like caused by excavating hard rock under the condition are higher and higher, and the risks and the severity of casualties, construction period delay and economic loss are higher and higher. Therefore, the effective prevention and control of deep shaft rock burst has great significance for ensuring the life safety of constructors and the efficient construction of the shaft.

Pressure relief blasting is one of the most important ways to prevent and treat rock burst at present. The aim of preventing and controlling rock burst is achieved by constructing a drill hole in the rock mass with great rock burst tendency and performing loosening blasting at the end part of the drill hole to release energy in the surrounding rock. However, pressure relief blasting has significant drawbacks in preventing wellbore rock burst. Firstly, secondary power disturbance formed by pressure-relief blasting on surrounding rocks has great influence on the stability of a shaft, and particularly, the shaft wall rock mass is easy to damage when the dosage is overlarge; secondly, the pressure relief blasting is only for pressure relief of one point, and a continuous broken rock stress relief layer cannot be formed in the surrounding area of the whole shaft, so that the pressure relief effect is not ideal. Another common method of mitigating rock burst is water flooding, where the risk of rock burst is eliminated by flooding the hole with high pressure water to weaken the surrounding rock. However, for the hard rock with better integrity, the water injection has small scope and long time for preventing rock burst due to the poor rock permeability.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a method for preventing and treating rock burst of a shaft by using high-pressure water jet, which utilizes high-pressure water beams to directionally crush rock masses to form a crushing zone surrounding the shaft, and simultaneously, high-pressure water can penetrate through cracks of the rock masses to soften surrounding rocks, thereby achieving the purpose of efficiently preventing and treating the rock burst.

In order to achieve the purpose, the invention adopts the following technical scheme:

a method of controlling wellbore rock burst using high pressure water jets, comprising the steps of:

(S1) uniformly drilling more than 3 advanced pressure relief drill holes on the well wall, wherein the hole diameter of each drill hole is preferably 38-50 mm, the axial projection distance of the hole depth in the shaft is the same as the footage distance of the shaft, and the axial included angle between the drill hole and the shaft is preferably 30-60 degrees;

(S2) putting the high-pressure water jet pipe into the drilled hole, putting a spray head connected with the high-pressure water jet pipe at the bottom of the drilled hole, and spraying water beams through the spray head to break rocks to form a perforated hole;

(S3) continuously rotating the high-pressure water jet pipe, adjusting the jet direction of the spray head, obtaining a plurality of perforation holes with the same depth and positioned on the same plane, and forming a circular cutting groove with the spray head as the center of circle;

(S4) repeating (S2) - (S3), and forming circular cutting grooves at the bottoms of the boreholes respectively, wherein the perforation depth and the orientation corresponding to each circular cutting groove enable every two adjacent circular cutting grooves to intersect, and a communicated annular shaft crushing zone is formed outside the shaft wall, preferably, the diameters of the circular cutting grooves are the same, and the circular cutting grooves are parallel to the longitudinal section of the shaft.

Preferably, the number of the drilled holes is 8-12, and the drilled holes are uniformly distributed at intervals of 30-45 degrees along the circumferential direction of the shaft.

Preferably, the inner diameter of the high-pressure water jet pipe is 5-10 mm, and the outer diameter of the high-pressure water jet pipe is 10-20 mm.

Preferably, the length of the spray head is 6-10 mm, the inner diameter is 4-6 mm, and the outer diameter is 8-12 mm.

Preferably, evenly set up a plurality of diameter along the shower nozzle hoop and be 2 ~ 3 mm's nozzle, nozzle quantity is preferably 4, along shower nozzle hoop every 90 evenly distributed.

Preferably, the nozzle head is axially perpendicular to the longitudinal section of the wellbore and the nozzle axis, respectively.

The invention has the beneficial effects that:

(1) the continuous annular shaft crushing zone is formed in advance on the working face, the rock mass with strong rock burst tendency is subjected to advanced pressure relief, compared with the traditional single-point pressure relief, high stress and high energy in surrounding rock can be effectively relieved, the phenomenon that the stress and the energy of the surrounding rock are gathered in a non-relief area to induce large-scale rock burst is avoided, the shaft is excavated in the annular shaft crushing zone, the rock burst disaster is prevented and treated in advance, and the construction safety is good.

(2) The high-pressure water jet not only can release pressure by crushing a rock body, but also can soften surrounding rocks, induce the expansion, the communication and the fusion of rock body fractures, fully utilize the advantages of two rock burst prevention and control methods of pressure release and water injection, realize the purpose of efficiently preventing and controlling rock bursts, and effectively solve the problem of safe construction of a high rock burst outburst shaft.

Drawings

FIG. 1 is a diagram of a borehole layout;

FIG. 2 is a cross-sectional view A-A of FIG. 1;

FIG. 3 is a schematic structural view of a high-pressure water jet pipe and a nozzle in a borehole;

FIG. 4 is a cross-sectional view B-B of FIG. 3;

FIG. 5 is a diagram of wellbore rockburst control effectiveness;

FIG. 6 is a cross-sectional view C-C of FIG. 5;

FIG. 7 is a cross-sectional view taken along line D-D of FIG. 5;

in the figure: 1-a wellbore; 2, drilling; 3-a high-pressure water jet pipe; 4-a spray head; 5-a nozzle; 6-ring wellbore fracture zone; 7-perforating; 8-circular cutting groove.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Referring to fig. 1-7, the method for preventing and treating rock burst of a shaft by using high-pressure water jet of the invention comprises the following steps:

the method comprises the following steps: 8-12 advance pressure relief drilling holes 2 are uniformly drilled in the wall of a shaft 1, the hole diameter is 38-50 mm, and the axial projection distance of the hole depth in the shaft 1 is the same as the advancing distance of the shaft 1. For guaranteeing even release effect, avoid simultaneously drilling 2 to cause the destruction of excavation in-process well wall rock mass, drilling 2 is 30 ~ 60 with the contained angle of vertical direction, along 1 hoop of pit shaft every 30 ~ 45 evenly distributed.

Step two: putting a high-pressure water jet pipe 3 with the inner diameter of 5-10 mm and the outer diameter of 10-20 mm and a spray head 4 with the length of 6-10 mm, the inner diameter of 4-6 mm and the outer diameter of 8-12 mm into the bottom of a drill hole 2, uniformly arranging 4 nozzles 5 with the diameter of 2-3 mm at intervals of 90 degrees in the circumferential direction of the spray head 4, pressurizing water by using a high-pressure or ultra-high-pressure pump to form water beams with high speed, high energy and high penetrating power, and ejecting the water beams through the nozzles 5, so that 4 perforating holes 7 with a certain depth are formed by crushing rocks. In this embodiment, the axial direction of the nozzle 4 is perpendicular to the longitudinal section of the shaft 1 and the axial direction of the nozzle 5, so that the jet direction can be controlled better.

Step three: slowly rotating the high-pressure water jet pipe 3, adjusting the jetting direction of the nozzle 5, forming 4 perforating holes 7 with the same depth on the plane where the nozzle 5 is located, and continuously rotating the high-pressure water jet pipe 3 until forming a circular cutting groove 8 which takes the spray head 4 as the center of a circle and is parallel to the longitudinal section of the shaft 1. The embodiment carries out directional water jet rock breaking in the tangential direction of the shaft 1, has small disturbance to the radial rock mass of the shaft 1, greatly reduces the secondary disturbance damage to the shaft 1, and is favorable for the efficient and safe construction of the shaft with high rock burst tendency.

Step four: circular cutting grooves 8 which are the same in size and parallel to the longitudinal section of the shaft 1 are formed at the bottom of each drill hole 2 by the same method, every two adjacent circular cutting grooves 8 are intersected, a communicated annular shaft crushing zone 6 is formed outside a well wall, advanced continuous pressure relief is realized, meanwhile, high-pressure water can soften surrounding rock through rock body cracks, the advantages of two rock burst prevention and control methods of pressure relief and water injection are effectively combined, and the rock burst prevention and control method is good in rock burst prevention and control effect and high in efficiency.

And after completing one advancing distance, repeating the steps from one to four until the shaft construction is finished or at least ensuring that the shaft construction of the rockburst risk area section is finished.

The above embodiments are only for illustrating the technical solutions of the present invention and are not limited thereto, and any modification or equivalent replacement without departing from the spirit and scope of the present invention should be covered within the protection scope of the technical solutions of the present invention.

Claims

1. A method for preventing and treating rock burst of a shaft by using high-pressure water jet is characterized by comprising the following steps:

(S1) uniformly drilling more than 3 advanced pressure relief boreholes in the borehole wall;

(S4) repeating the steps (S2) - (S3), and forming circular cutting grooves at the bottoms of the drill holes respectively, wherein the perforation depth and the orientation corresponding to each circular cutting groove enable two adjacent circular cutting grooves to be intersected pairwise, so that a communicated annular shaft crushing zone is formed outside the well wall.

2. The method according to claim 1, wherein the bore diameter is 38-50 mm, and the projection distance of the bore depth in the axial direction of the shaft is the same as the shaft footage distance.

3. The method of claim 1 or 2, wherein the angle between the axial direction of the borehole and the axial direction of the wellbore is 30-60 °.

4. The method according to claim 1 or 2, wherein the number of the drilled holes is 8-12, and the drilled holes are uniformly distributed along the circumferential direction of the shaft at intervals of 30-45 degrees.

5. The method of claim 4, wherein the circular cutting grooves formed in the bottom of each borehole have the same diameter and are parallel to the longitudinal section of the wellbore.

6. The method of claim 2, wherein the high pressure water jet pipe has an inner diameter of 5 to 10mm and an outer diameter of 10 to 20 mm.

7. The method of claim 6, wherein the nozzle has a length of 6 to 10mm, an inner diameter of 4 to 6mm, and an outer diameter of 8 to 12 mm.

8. The method according to claim 7, wherein a plurality of nozzles with the diameter of 2-3 mm are uniformly arranged along the circumferential direction of the spray head.

9. The method of claim 8, wherein the number of nozzles is 4, evenly distributed every 90 ° along the circumference of the head.

10. The method of claim 8, wherein the injector head is axially perpendicular to the longitudinal section of the wellbore and the nozzle axis, respectively.