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为了获得预选处置库区现今地应力的赋存特征,在该区花岗岩体内的4个深钻孔中采用水压致裂方法进行地应力测量。基于钻孔岩芯编录结果,在0~700 m深度范围内,成功取得地应力量值和最大水平主应力方向数据。依据获取的地应力实测资料,结合拜尔利定律和断层摩擦库伦准则,对预选区的地应力状态及断层活动性进行分析。结果表明:(1)3个主应力随深度呈现出较好的线性关系;(2)测试深度范围内,水平应力普遍高于垂向应力,预选区构造应力占主导地位,且随深度的增加逐渐减弱,岩体北部的水平力作用强于中部及南部,南部最弱;(3)最大水平应力优势方位为NEE,与区域构造应力场方向基本吻合,自青藏高原内部及边缘到东天山地区,现今最大主应力的作用方向表现为由NE~NEE的变化规律;(4)预选区地应力量值未达到断层摩擦滑动临界值,断层活动性较弱;(5)研究成果为处置库的开挖设计和稳定性评价提供科学的指导,实测资料填补了该区域地应力数据的空白,为我国西部地区地应力场分布规律研究提供重要参考资料。
In order to obtain the characteristics of present geostress in pre-selected reservoir areas, hydraulic fracturing method was used to measure the in-situ stress in four deep boreholes in the granite. Based on the drilling core cataloging results, the values of the geostress and the data of the maximum horizontal principal stress are successfully obtained in the depth of 0 ~ 700 m. Based on the measured data of the in-situ stress and the Bealey law and the Coulomb criterion of the fault friction, the geostress status and fault activity of the preselected area are analyzed. The results show that: (1) The three principal stresses show a good linear relationship with depth; (2) Horizontal stress is generally higher than vertical stress in the range of test depth, and the tectonic stress in the preselected area dominates. With the increase of depth (3) The maximum azimuthal stress azimuth is NEE, which is consistent with the direction of regional tectonic stress field. From the inside and the edge of the Tibetan Plateau to the east Tianshan area (4) The value of the prestressed ground stress does not reach the critical value of the friction and slip of the fault, and the fault activity is weak. (5) The research result is the result of the change of the NE- Excavation design and stability evaluation to provide scientific guidance. The measured data have filled the blank of the regional stress data and provided an important reference for the study of the distribution law of the geostress field in the western China.