某电站坝区左岸深部裂缝特征及成因机理浅析

Features and Formation Mechanism of Deep Fracture in Left Bank Slope of Some Hydropower Station Dam Site

水电工程常建在高山峡谷地带,这样的地势条件决定了常遇到深部拉裂问题。深部裂缝是指在微新岩体中发育的张性破裂或破裂带。拟建水电站坝区左岸存在大量的深部拉裂缝,通过对其发育分布、变形特征的考察,提出了左岸深部裂缝是在特定较高地应力环境和岩性条件下,伴随河谷快速下切,岸坡岩体中积存的应变能强烈释放,使原先较高的地应力得到释放,并由于岸坡特有的岩体特征产生差异回弹,坡体内原有的构造结构面浅表生改造的产物。

Hydropower project is usually built on high mountain canyoned fiver reaches, then this terrain condition causes deep factures. And the deep fracture means the sheeted fracture or fracture zone in fresh rock mass. There are a lot of deep faetures in the left bank of the proposed hydropower station dam site. This paper analyzes distribu- tion characteristics and deformation behaviors. It is concluded that the deep fracture is the product of epigenetic re- formation of structural plane of original constitution in rock mass which is caused by high ground stress , lithology and quick valley cutting, then strain energy in rock loosens strongly and high ground stress releases, and specific rock characteristics have different restoring origins.