Exploration of numerical simulation on paleo-tectonic stress field

Abstract

This paper analyzed the numerical simulation method of Paleo-tectonic stress field from three aspects: tectonic simulation target, establishment of the tectonic model, and tectonic modeling. Taking Chengzhuang coal mine of Jin city in Shanxi Province as an example, based on field investigations on macro and micro tectonic features, we established plane-stress model and 3d geological model at first, and selected mechanical parameters of rock mass, boundary condition and failure criterion of rock, then, determined the magnitude of palaeo-tectonic stress and the loading sequence of stress by using of large scale numerical simulation software ANSYS and FLAC. The simulation results show that two stages of large tectonic movement should have taken place at Chengzhuang coal mine in history, that is it is in east-west direction at first, and then turned to south- north direction; and the magnitudes and directions of tectonic stress are 60Mpa, east- west direction, and then 110 Mpa, south north direction respectively. This tectonic action could meet most shear joints on the earth and in the 3# coal rock taken place simultaneity. The region with a weak resistance capacity to deformation is easily destroyed in uniform stress field, because the shearing resistance capacity of rock mass namely internal friction angle was different. This analysis has an important significance to risk zoning and gas outburst regional predicting in coal mine.