三峡工程大坝建基岩面开挖轮廓设计及实践

Design and implementation of foundation rock surface excavation at TGP

三峡坝址工程地质条件优越。如何根据这种优越的条件来设计大坝建基岩面的开挖轮廓 ,达到既安全又经济的目的 ,一直是勘测、设计和科研等方面的重要研究课题。这一问题已经得到满意的解决。这里 ,就①坝址岩体风化特征和可利用岩面选定 ,和②坝基岩面开挖轮廓设计及基础处理进行介绍。后者包括一般规定 ,开挖控制及岩面修整、基础固结灌浆、基础高差及台阶规定、河床风化深槽处的开挖深度、缓倾角结构面与深层抗滑稳定和地质缺陷的处理等。

TGP damsite has an excellent engineering geology condition.It has been an important subject for investigation,design and research engineers to study how to design the excavation outline of the dam foundation rock surface according to such an excellent condition,so as to achieve both safe and economic purpose.This question has been satisfactorily solved.In this paper,the following contents are described:(a) weathering characteristics of dam site rock mass and selection of utilizable rockbed,and (b) design of excavation outline of dam foundation rock surface and foundation treatment.The latter includes general provisions,excavation control and excavated rock surface trimming,foundation consolidation grouting,specified foundation surface height difference and berm width,excavation depth at the deep weathering trough on the riverbed,low-dip-angle structure plane and stability against deep slide,and treatment of geologic defects etc..