Research on Evolution Mechanism and Prevention of Rock Burst in Deep Coal Seam Excavation Roadway
Supervisor:guo wei jia kong ling hai
Rock burst is a catastrophic dynamic phenomena which is caused by rock pressure around stope and roadway.As a difficult problem both at home and abroad,the research of prevention and control of rock burst has been paid attention to by domestic and foreign academic circles.With the increase of rock burst accidents in many deep mining mines in our country,the research on the prevention and control of rock burst in deep mine has become a major safety technical problem to be solved.The academic and engineering circles at home and abroad have made a lot of achievements on the damage mechanism and evolution law of the surrounding rock of deep roadway,which have play a guiding role in supporting and controlling surrounding rock of deep roadway.However,there are still many problems in the mechanism of rock burst in deep roadway.For example,the cognition of the dynamic development law and distribution characteristics of the surrounding rock in the deep roadway is deficient;the study on inoculation mechanism of rock burst in deep roadway and the relationship between the mechanism and the space structure of damaged surrounding rock.In this paper,aiming at the problems of the prevention and control of rock burst,taking coal roadway in kilometer deep shaft of Tengdong coalfield as engineering background,the mechanical mechanism of the rock burst in the deep roadway is studied systematically,from the angle of the evolution process happening on the spatial structure of the surrounding rock of deep roadway.The main achievements are as follows:(1)Considering the two main factors of geology and engineering,the principal stress condition and stress state when deep rock mass rupture are obtained.Based on the actual conditions of the site,the engineering geological conditions of surrounding rock of deep excavation tunnel are analyzed by means of theoretical analysis and numerical simulation.The influence of engineering geological conditions on rock mass stress is given.Five kinds of principal stresses in deep rock mass are studied.It is considered that the concentration or adjustment of deep principal stress is the precondition of rock mass fracture,and the change of principal stress difference is the reason for the development of fracture.(2)The surrounding rock of deep roadway is divided into five regions with different mechanical properties,and the characteristics of the difference between the bearing area of the deep roadway and the surrounding rock of the plastic zone are obtained.The general rule about the failure of surrounding rock is analyzed based on the elastic-plastic theory.In view of the stress state and failure characteristics of the surrounding rock in deep roadway,a partition model of the surrounding rock in deep roadway is put forward.And the characteristic of the difference between the bearing area and the plastic zone after failure is given.(3)The spatial structure model of the surrounding rock roadway in deep roadway is established.This paper analyzes and studies the dynamic evolution law of the surrounding rock in deep roadway by means of numerical simulation and field measurement.(4)The dynamic model of "wedge-wall" in the surrounding rock of deep roadway is established.Based on the analysis of the stress state of surrounding rock mass,two kinds of unstable failure modes of surrounding rock are obtained.(5)Based on the model of surrounding rock in deep roadway,a kind of similar simulation test method is developed,and this paper presents a new method to study the impact failure of surrounding rock in deep mine roadway.In view of a new type of similar simulation test device for the stress damage of the surrounding rock in deep mine,considering the situation that the depth of the plastic zone and the coefficient of horizontal pressure are both large,through the simulation test system of roadway in deep mine,the dynamic process of deep excavation tunnel from the excavation to the impact instability of surrounding rock is reconstructed by using the large scale model and the method of two-way loading pressure.And the stress distribution characteristics of surrounding rock in deep mine from high stress static load to dynamic instability under dynamic loading are analyzed.The device can not only simulate the impact failure characteristics of the surrounding rock,but also simulate the static damage characteristics of deep roadway at the same time.(6)Based on the structural model of the surrounding rock of deep roadway and its characteristics,the paper analyzes the self organization characteristics of damage of surrounding rock in deep roadway.The mechanism of impact mechanics of deep driving roadway is studied.And the technical scheme for the prevention and control of rock burst under different geological conditions in deep mine is proposed in this paper.