Study on tectonic stress environment based on Stereographic Projection Method

In order to improve the analysis reliability of the tectonic stress environment,with the study on the conjugate shear joints,the fracture surface scratch and other tectonic traces,the Stereographic Projection Method was applied to rebuild the tectonic stress information of Pingdingshan No. 8 Mine area,to analyze the period of the tectonic stress environment and to determine the basic features of the tectonic stress environment in the area. The study result showed that there was no shear joints existed in the rock movement and the angle bisector of the acute angle was the max stress direction. When the shear joints existed in the rock movement and was the same direction,the angle bisector in a dislocation direction was the max stress direction. The tectonic stress environment in the study area was divided into three periods. The max stress in the Indosinian period was in a direction of NE-SW. The max stress in the Yanshanian Period was in a direction of NW-SE and the max stress in the Himalayan Period was in a direction of NEE-SWW. The results were basically fitted with the stress data obtained from the seismic source mechanism by the predecessor,and thus the method would have a good suitability to the study on the tectonic stress environment of the underground engineering.