Mechanism Of Burst Start-up Of Rock Burst And Its Application

In order to make the mechanism and the monitoring, prevention and control theory of rock burst are interrelated and unified. Research methods such as case analysis, numerical simulation, laboratory test, theoretical analysis, field application verification, etc., are used. Taking the evolution of rock burst as the breakthrough point, the evolution of rock burst is revealed by the "three stages", the internal and external causes of the impact load are pointed out, the mechanism of the dynamic instability of the material and the structure of the burst is obtained, the type, mechanical model and criterion of burst initiation are established. At last, the theory of burst start-up of rock burst is put forward, the monitoring and control technology system based on the theory of impact initiation is established.Research results show that:(1) The factors influencing the occurrence of rock burst are complex and changeable, but they come down to the two source of load(concentrated static load and concentrated dynamic load).There are three sequential stages of the burst start-up, burst energy transfer and rockburst pressure behavior. Two kinds of loads have the impact on the occurrence of rock burst, just to affect the link named burst start-up, rather than the whole process of rock burst.(2) The tunnel can be seen as the engineering structure, which is composed of the roof-coal seam-floor, the hole. Localization of load in engineering structures, the coal body has the elastic zone and plastic zone, and there are time varying characteristic in the boundary and the loads of each zone. The burst start-up zone is the limit equilibrium zone for the roadway and also the main bearing area of the tunnel engineering structure.(3) The variable load structural mechanics model which similar to architecture is established. Through the analysis of the limit equilibrium equations of the main bearing carrier and its foundation of architecture, with the increase of the vertical load in the main bearing area, the stick slip burst trend of the main bearing carrier is reduced.And the damage of the material and the damage of the foundation is increasing.The essence of burst start-up is a single elastic brittle material structure breakthrough material strength limit, then material instability, causing structural instability of engineering structure, including the transformation process from the material instability to the structural instability.(4) There are two main types of load source of burst start-up:the concentrated static load and the concentrated dynamic load, and the other factors are the internal combination mode of the load. The research results show that rock burst stat-up from the floor in whole coal roadway because of the high stress concentration in both side of roadway, and the floor only is the carrier of energy transfer and release, which show the location of rock burst occured. The energy criterion of burst stat-up is the sum of the concentrated static load and the concentrated dynamic load more than the minimum energy required in the area of the limit equilibrium of the excavation space.(5) Through theoretical analysis and application verification, the theory of burst start-up of rock burst is put forward, which includes four layers:the evolution process of rock burst, the internal and external relations of the load sauces of burst start-up, the burst start-up area and the starting principle are revealed; the analysis of the classification and the load criterion.(6) The important theoretical guidance for the follow-up monitoring and control of the theory of burst start-up is expounded.Based on the theory of burst start-up, the local control method of rock burst is proposed. In the two kinds of typical rock burst coal mine has been proved to be very good.