某水电站坝址F_(41),F_(42)断层泥化带工程特性研究

某峡谷区水电站坝址发育有区域性断裂穿越大坝河床近岸坝基(不属于活动断裂),将其分为碎裂岩带和F41,F42断层软弱构造岩带,其中F42为泥化带,系拟建水电站最大坝高200m级坝基最软弱部位。为了提供该水电站工程设计所需的工程地质资料,在查明F41,F42断层发育几何学特征的基础上,通过勘探技术、取样室内物理力学性质试验、平洞内现场原位力学性质试验、现场原状样渗透变形试验研究其工程特性,并以试验成果为基础,提出断层泥化带主要物理力学性质及渗透性参数建议值。研究结果表明:断层泥化带工程性状差,须采取工程处理措施。可为其它工程遇到类似断层时类比参考。

The Engineering Properties of F41 and F42 Fault Muddy Zone at the Dam Site of Hydropower Station

The dam site of a hydropower station planned to be built in a gorge area has developed inactive and regional fault passing through the river bankside dam foundation.The fault can be divided into cataclasite rock belt and F41,F42 weak tectonic fault zones,which,known as fault muddy zones,are the weakest part in the dam foundation of the above hydropower station whose maximum dam height is more than 200 m.To provide geological data for the hydropower project design,we studied the engineering characteristics of the F41 and F42 fault muddy zones on the basis of their geometrical features by means of engineering investigation,indoor test on the physical and mechanical properties of samples,in-situ adit test on the mechanical properties,and seepage deformation test on undisturbed samples.According to the test results,we proposed the recommended values of main physico-mechanical properties and permeability parameters of the fault muddy zones.The research results indicate that treatments must be taken on the fault muddy zones owing to its weak engineering properties.It would provide reference for similar faults of other projects.