黄河龙羊峡电站坝区F_7断层新活动性问题的工程地质研究

本文根据断裂动力学、古地震及现代应力积累问题等方面的分析结果,对龙羊峡电站坝区F7断层新活动性特征进行了深入的研究。查明该断层是一条第四纪以来多次活动的古粘滑型发震断层,其最新活动休止时间为晚更新世中晚期,现今应力积累程度只达37.9％,在工程年代内该断层处于相对稳定状态。研究中,现代测试技术的应用有效地解决了分析中的一些重要问题。综合运用热发光绝对年龄测定和石英颗粒表面结构扫描电镜研究,为鉴定断层的最新活动年代提供了新的有效方法;热释光温度测定方法则开拓了研究断层粘滑活动性的新途径。

RESEARCH ON RECENT ACTIVITIES OF A FAULT NEAR THE DAMSITE OF LONGYANG GORGE HYDRO-ELECTRICAL POWER STATION

Based on the data obtained from field investigations, the recent activities of a fault near the Damsite of Longyang Gorge Hydroelectrical Power Station is dealed with in this paper. It is shown that the fault is an ancient seism-generating fault which had been reactivated on many occasions before Late Pleistocene, and has stopped moving since then. The present level of stress accumulation along the faulf is estimated as 37.9 per cent only, so it will be stable in the near geological future. Modern techniques including thermoluminescent dating and surface structure electron-microscopic scanning of quartz grains have been applied to date the recent fault activity and to determine its dynamic characteristics.