构造活动地区工程构造稳定性研究

STUDY ON ENGINEERING STABLITY IN TECTONICALLY ACTIVE REGION

拟建的新疆喀拉喀什河乌鲁瓦提水电站位于现代地壳运动十分活跃的区域。野外证据显示出，坝区的Ｆ＿（１２）断层新活动延续到晚更新世，电站附近的石门北断层在第四纪有活动。对采自坝区及附近几条断层的断层物质样品进行了变形显微构造、石英颗粒表面形貌和微结构类型、ＴＬ年龄的分析测定，结果表明，Ｆ＿（１２）最新活动的上限时间不晚于３万年，Ｆ＿（３０）和石门断层的活动持续到晚更新世，石门北断层最新的活动的上限时间约２万年。根据区域断裂的分布和应力场的情况，进行了构造模拟实验，预测出工程区在区域应力场的继续作用下，应力集中在远离坝址的部位，坝址附近不会出现新的应力集中点。总体看，所选坝址是地壳活动区中相对较稳定的地段。

The Wuluwati Hydropower Station on Kalakashi River in Xinjiang is located in an area with recent high active tectonic movement.The field evidence shows that fault F12 at the dam site exhibited multiphase activity up to the late Pleistocene,and faulting occurred on the North Shimen fault in the neighboring area in the Quaternary.We analysed the samples of fault materials collected along the faults at dam site and its surroundings by means of analysis of microstructures,quartz surface textures and TL dating. The results indicate that the upper time limit of the last faulting is about 30 and 20ka BP along the fault F12 and North Shimen fault,respectively,while the F30 and Shimen fault exhibited actitities by the Late Pleistocene.The structural model experiments based on distribution of the regional faults and stress field predict that stress concentration segment is located in an area far from the dam site. The dam area is a relatively stable segment.