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

摘要： 利用水压致裂原地应力测试技术,在乌鲁木齐市区碗窑沟断裂东段、雅玛里克断裂东段和西山断裂带中、东段开展了断层附近原地应力测量研究,得到了地表浅部构造应力的大小、方向和分布特征。钻孔HFZK3位于碗窑沟断裂东段的南侧,孔深62.13m;钻孔HFZK5位于雅玛里克断裂东段的南侧,孔深30.00m;钻孔HFZK9和HFZK12都位于西山断裂带的中、东段,孔深分别为34m和54.5m。根据实测的地应力资料,断层附近最大水平主压应力方向为NE—NEE向,与区域构造应力SN—NNE向主压方向有一些差异,说明受断层活动影响,断层附近的应力状态与区域应力场明显不同。利用地应力实测资料研究了断层的活动性,在测量深度域内水平和垂直应力的关系为σ_H>σ_h>σ_v,该应力状态有利于逆断层活动,与地质资料反映的以逆断层活动为主基本一致。利用库仑摩擦滑动准则,摩擦强度取0.6～1.0进行分析,断层附近的现今地应力状态达到或超过产生逆断层摩擦滑动的临界值,表明测区现今构造活动以逆断层为主。研究区的3条断层不具备发生走滑断层活动的可能性,其中雅玛里克断裂东段、西山断裂带中段和东段具有发生逆断层活动的可能性,相比而言,西山断裂带中段危险性更大。

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