某地区Chipwi韧性剪切带构造特征及其岩体工程性状

Formation and Rock Engineering Characteristics of Chipwi Ductile Shear Zone Somewhere in Southeast Asia

某拟建水电站工程地区发育有Chipwi韧性剪切带,宽约500~800 m,系区域上顺主干河流不具活动性的May Kha断裂构造形迹组成的骨架,穿越混凝土重力坝左岸坝基。采用构造地质学方法研究其构造特征,对该地区区域构造的认识具有十分重要的意义;采用工程地质学方法研究其岩体工程性状,可为水电站工程设计提供技术支撑。研究结果表明;该韧性剪切带内物质组成主要为具有强烈定向组构的粗糜棱岩,经历了不同时期多期次不同性质的构造活动。在韧性变形之后很晚的时期,区域上沿早期韧性剪切变形较强的变形带或者韧性剪切带边缘,发育了脆性变形叠加在韧性变形带之上。经其岩体工程性状研究,工程可容易利用的微新状岩体能满足工程要求,对拟建水电站工程建设无不利影响。

The Chipwi ductile shear zone is developed across the planned site of a proposed hydropower station project , with the width of 500-800m.It is the skeleton of the inactive May Kha fault along the mainstream across the area ,cutting through the left bank foundation of the concrete gravity dam .Studying the tectonic characteristics of the area using geotec-tonic methods has a significant value to getting familiar to the geological structure of the area;Rock engineering research can provide technological support for the engineering design of the hydropower station .We have found out that this ductile shear zone is mainly made up by coarse mylonite with strong oriented structure ,and it has experienced multiple character-istics of tectonic movements through different time periods .At far later period after the ductile deformation ,brittle deform-ation has developed over the ductile deformation along the earlier formed deformation zone .The result of our rock engi-neering research shows that the newly shaped rock mass can meet the engineering requirements and it has no negative in -fluence on the hydropower station to be constructed .