摘要
在工程建设中,工地及其邻近地区的断层活动性质及最后一次活动时间是工程设计的一项重要依据。本文以我国西南地区拟建的某大型水电站坝址区的断层为例,讨论了根据断层物质揭示断层活动性质及最后一次活动时间的理论依据、工作方法及研究结果。研究表明,某工区内切穿二叠纪、三叠纪石灰岩的F_8断层的最后一次活动时间大约在20万年以前;在近东西向的主压应力作用下断层运动以右旋走滑为主;断层活动过程中的差异应力为5×10~7Pa,最大可达10~8Pa以上。
During engineering construction, the nature and time of the latest phase of fault activity in the work site and its adjacent region is one of the most important bases for safety design. Taking the fault in a dam site in Southwest China as an example, where a huge power station is planned to be constructed, this paper discusses the theoretical foundations, working methods and research results concerning the nature of the fault activities and the time of the latest phase revealed by fault materials. It is shown that the latest activity time of fault Fa cutting through the Permian and Triassic limestones is about 200,000 years ago; under the action of nearly EW-oriented principal compressive stress, the fault movement is mainly in a mode of right-lateral strike-slip; and that the average differential stress during the active period was aboul 5 × 107 Pas and the maximum value might reach 108 Pa or more.
出处
《地震》
CSCD
北大核心
1989年第5期66-75,共10页
Earthquake
