关键词: 北京房山, 花岗闪长岩体, 应力状态, 附加应力分量, 旋扭构造

Abstract: According to an analysis of in-situ stress measurements, on the whole, activity of general NE-trending Babaoshan, Huang zhuang and Gaoliying fault zone is considered as clockwise torsion Characters of in-situ stress state on different segments of the fault zone differ from main directions of the maximum horizontal compressive stresses in the Beijing-Tianjin-Tangshan area. General NE-trending fault zone shows tensile antitorsion components from the additional stress state calculated by stress principle of stress superposition of elastic theory. The fault segments in Dahuichang and Niukouyu zones have the same character as well. The stress state in this region is still considered as one in adjusment period after the major Tangshan earthquake. It seems that the stress state determined in deeper crust is affected by the tectonic activities too.

Key words: Beijing, Granodiorite mass, Stress state, Additional stress component, Rotation-torsion structure