Study On The Relation Of Roof Stress Accumulation And Coal Pillar Stress Change Of The Deep Buried Coal And Influenced By Fault

As one of the most dangerous mining the geologic hazards,the rock burst, occurs with high frequency.The problems of rock mechanics caused by the deep mining engineering are the focuses in the fields of mining engineering and rock mechanics.The rock burst is influenced by many factors, mainly is the condition of thick and stiff Peak, the condition of stiffness and brittleness of coal, the condition of high ground stress and the stress concentrate areas because of Excavation. In order to make the design and layout of the coalmine reasonable, the paper, based on the concretely geological condition of deep buried coal in Zhaolou coalmine, combined the structure and geophysical information, a test of mechanics character of rock and coal is carried, centrifugal model experiment is carried, geological and mechanical model is set up and is analyzed, a numerical simulation analysis is completed. The main conclusion of the paper is follow:Based on the region structure and geophysical information of Zhaolou coalmine, the structure characteristic is analyzed, the law of structure evolvement is explained, the law of distributing and combination of the structure is systemic studied, the main structure and it's constitutive net is obtained.This paper started with the experiment of coal burst tendency that was conducted in main mining coal seam.Through the experiment and analysis of the impact energy index,elastic energy index,dynamic destruction time of coal sample,and the Bending energy index of rock sample,the rock burst tendency of the coal is high and the tendency of rock is weakA centrifugal model simulation is processed in order to study the law of deformation and stress distributing because of different roof conditions. As a result of coal mining, coal pillar at the places of first cut, coal in front of workface, direct roof strata and basic roof strata, the rock stress and deformation is different. Three sets of models are built ,they are the conditions of the integrity of the roof , the excavation direction athwart the tendency of the structure ,just as the condition of normal fault and the excavation direction toward the tendency of the structure ,just as the condition of reverse fault .Because of the damage of the integrity of rock roof, the stress redistribution in the structural parts to form a concentration of tectonic stress, it is triggered shocks to the risk of pressure parts, but the extraction process can also lead to structural differences in the impact.According to the geology model when workface encounters fault, two mechanics model are built, one is the workface uncovers fault, another is workface just crosses fault, they are different, because of restriction condition, the coal roof mechanics behaviors are different when workface before and after the fault. The most shear strength and moment are happened at different place, when workface is nearer to fault, coal bed between the workface and fault just like coal pole, the bearing pressure rises with the workface advances, coal side is easy to crush, it is controlled by the coal intensity of pressure.FLAC2D software is used to carry out a numerical simulation analysis, to obtain a different model of the structure of the roof conditions in the process of mining, coal pillars, direct roof and basic roof the stress distribution and deformation characteristics of a comprehensive comparison of the results of simulation reflects the process of mining coal pillars and Poly roof pressure and fault structure of the impact of their characteristics. Mining the course of a complete roof structure and deformation of the basic state symmetry, and the fault cutting roof stress distribution and deformation of migration occurred in the fault surface structure of discontinuous parts of the deformation and stress distribution of concentration is very obvious.