苗尾水电站砾质土心墙堆石坝设计

The Design of the Gravelly Earth Central Core Rockfill Dam of Miaowen Hydropower Project

苗尾水电站砾质土心墙堆石坝,工程场地地震基本烈度为VII度,地形地质条件复杂。坝壳料主要采用的溢洪道开挖料,岩性偏软,粒型偏差;心墙砾质土料料源复杂,天然含水率变化大。结合"基础地质条件差、地震烈度高、土料含水率变化大和坝料岩性偏软"等工程特点和难点,从坝基处理设计、坝体结构设计、筑坝材料设计和抗震措施设计等方面进行了大量的专题研究。目前坝体监测成果表明坝体沉降变形、应力应变符合一般规律且数值合理,大坝安全是有保障的。

The gravelly soil central core rockfill dam of Miaowei hydropower project is located in a region where the basic seismic intensity is classified as degree Ⅶ and both topographical and geological conditions are complex. The dam shell is mainly composed of the spillway excavations which are characterized by rock being lithologically soft and shape of grain being poor, while the gravelly soil core material borrowed from different areas and its natural moisture content greatly changes. Therefore a lot of special studies have been made on design of dam foundation treatment, design of dam structure, design of dam material and dam earthquake-resistant design according to the engineering characteristics and the key problems of “poor foundation geological conditions, high seismic intensity, changeable moisture content of soil material and lithologically soft dam material”. The dam instrumentation results show that both settlement and stress of the dam body conform to the general law and the values are reasonable so that the dam is proved safe.