Geo-mechanical Model Test and Study of Xiaowan Arch dam Abutment Stability

The Xiaowan reservoir plays a leading role in developing of cascade hydropower plants in the middle and lower reaches of the Lancang river,and the Xiaowan dam is a double-curvature arch dam,292m high.The dam site is topographically suitable for constructing a high arch dam,however its geological conditions are rather complicated.According to the topographical and geological conditions of the Xiaowan arch dam abutments located at EL.1,210m the geo-mechanic model test method has been used,taking into account the major factors which have impacts on the abutment stability.The overloading method has been used to carry out failure test and study,analyze deformation distribution characteristics of both dam body and abutments,study process,pattern and mechanism of failure,which might make the abutments unstable,and finally determine the stability of the abutments under overloading condition.