The research of three-dimensional initial in-situ stresses field in mine can put forward the suggestion on the production design of coal mine and the prediction of coal and gas outbursts. Based on the geological materials about Tian-fu San-hui No.1 mine in Chongqing, the 3D FEM model is built, and the numerical modeling of initial in-situ stresses field is finished with the elastoplastic finite element method by use of ANSYS program. According to the modeling results, the characters of the in-situ stresses both of San-hui No.1 mine and K1 coal seam are analyzed. The study shows that by building the geological model from the earth's surface, the influence of terrain on initial in-situ stresses field has been studied; the coal and rock mass in Sanhui No.1 mine is under complex compressive stresses, both of the maximum principal stress σ1 and the minimum principal stress σ3 are mainly the textural stress at horizontal direction, the middle principal stress σ2 is mainly the overburden pressure, and there is an affinity between the direction of the principal stress and the tectonization of this area. It also indicate that the three-dimensional initial in-situ stresses field could be obtained legitimately by finite element modelling.
The coal and gas outburst, which threatens coal mine safety production, is an extremely complex geological power phenomenon that occurs in the coal mine production. In the last 150 years, since the first reported coal and gas outburst occurred in the Issac Colliery, Loire coal field, France, in 1843 , as many as 30,000 outbursts have occurred in the world coal mining industry. These disastrous mine outbursts have resulted in much loss of equipment, production time, even entire mines, and the lives of numerous miners all over the world.