关键词: 断层, 地应力, 水压致裂地应力测量, 库仑摩擦滑动准则, 乌鲁木齐市区

Abstract: In-situ stress measurement was carried out near the eastern segment of Wanyaogou Fault,western segment of Yamalike Fault,and middle-eastern segment of Xishan Fault in the urban area of Urumqi.The characteristics of tectonic stress magnitude,direction and distribution were obtained.The borehole HFZK3 is located on the south side of the eastern segment of Wanyaogou Fault,the depth is 62.13m;The borehole HFZK5 is located on the south side of the western segment of Yamalike Fault,and the depth is 30m;The boreholes HFZK9 and HFZK12 are located on the middle and eastern segment of Xishan Fault,and the depth are 34m and 54.5m,separately.According to stress measurement data,the direction of maximum horizontal principal stress is NE-NEE,different with the direction of regional tectonic stress of SN-NNE.This indicates that,effected by fault activity,the stress state near fault is obvious different with the regional tectonic stress field.The activity of fault zone is discussed using stress measurement data.The horizontal stress increases with depth,and its relation with vertical stress is σ_H>σ_h>σ_v.Such stress state is propitious to reverse faulting.The result is consistent with geological study.According to Coulomb friction criteria and taking m=0.6～1.0,the stress state near fault reaches or exceeds the critical value of generating frictional sliding along reverse fault,indicating that the current tectonic activity is reverse faulting.

Key words: fault, crustal stress, hydraulic fracturing stress measurement, Coulomb friction criteria, Urumqi City