摘要
拉西瓦水电站坝址论证阶段已查明,拟建坝址区内多个变形破裂体的潜在失稳严重危及着拉西瓦工程的顺利施工与安全运行,尤其是左坝肩ⅡB大型古变形破裂体已成为坝址变形体研究的关键问题。立足于大量的地面调查、多个平硐勘探与测试,本文首先介绍了ⅡB大型变形破裂体的变形破裂特征,并应用现场氡气探测裂缝深度等结果,界定了变形体的边界。其次,采用ESR方法对变形体内各典型裂缝进行了地质测年,分析了ⅡB大型变形破裂体的形成机制与形成演化过程,并探讨了该变形体的稳定性。研究表明,大多数裂缝都是在10万年以前形成,也证明了该变形体为一古变形体;在天然状态下ⅡB变形体目前整体处于稳定状态,但其表部和前缘有局部稳定性较差的部位。
Laxiwa hydropower station is one of important hydraulic projects on the Yellow River, and its success can make sure many people and their properties to be safe. However, a few deformable bodies, which were found in the dam area when the field investigation was done to choose the dam site, have been being the new problems in this project. Especially, the large-scale deformable body of ⅡB located at the left abutment of Laxiwa Dam endangered straightly and was really serious to the dam. Based on a great deal of site investigation, field exploration of tunnels, and testing, fracture characteristics of the deformable body was firstly described in this paper and some strong evidences were obtained to determine its boundary, which is ambiguous and different in previous studies. Also, the radon gas site monitoring along the various tunnels gave the boundary of the deformable body in depth. Then the typical fissures in the deformable body of ⅡB were dated by the method of ESR and the result showed that most fissures and the deformable body were originated in 100ka ago. Besides, the development mechanism and evolution of this deformable body were analyzed. Finally, the body stability was evaluated and the result indicated that the deformable body could sustain stability as a whole, while its surface and front parts might fail due to the affect from the construction.
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2006年第5期13-16,25,共5页
Hydrogeology & Engineering Geology
基金
国家973项目资助(2002CB412702)
关键词
拉西瓦
古变形体
形成演化
氡气测试
地质测年
Laxiwa
ancient deformable body
evolution
radon gas monitoring
geologic dating
