宁保辉 董振锋 韦哲

摘 要：受料场人工采砂影响，前坪水库人工扰动料储量占砂砾料料场总储量的80%，这种筑坝材料的力学特性成为影响大坝填筑质量的关键因素。通过开展人工扰动砂砾石料室内三轴剪切试验、流变试验、尺寸效应分析、数值模拟等，对其物理力学性质等进行了深入分析。结果表明，细粒含量低于最佳含量的砂砾石料压实后能满足设计要求，该种坝料是一种合格的筑坝材料。大坝填筑完成后，经过一个汛期蓄水运行，大坝沉降、水平位移、坝基坝体渗水量均较小，大坝结构安全。

关键词：砂砾石料;细颗粒缺失;人工扰动;土石坝;前坪水库

Abstract：In general， the optimal compaction can be achieved when the particle content of gravel （less than 5mm）is about 30%. Due to the influence of artificial sand mining， the particle content （more than 5 mm） of gravel in Qianping Reservoir is 74%-98%， and the content of fine particles is relatively small. The reserves of artificial disturbance materials account for 80% of the total reserves of the gravel quarry. The mechanical properties of artificial disturbance gravel become the key factors affecting the dam filling. Through triaxial shear test， rheological test， size effect analysis， numerical simulation and so on，its physical and mechanical properties were analyzed in depth. It is proved that the sand gravel with fine particle content lower than the optimum content can still meet the design requirements after compaction， This kind of dam material is a qualified dam building material. After the completion of the dam filling， the dam settlement， horizontal displacement and seepage of the dam foundation are small and stable， and the dam structure is safe.

Key words： sand gravel; loss of fine particles; artificial disturbance; earth rock dam; Qianping Reservoir

土石壩坝壳是维持坝体稳定的主体，是采用材料类型最多的分区。河南省前坪水库大坝黏土、反滤料和坝壳料总填筑量为1 275万m3，其中上、下游坝壳采用砂砾石料及开挖利用料填筑，砂砾石料总填筑量为885万m3。一般用于筑坝的砂砾石料小于5 mm的颗粒含量约为30%时，可以实现最优压实[1]。前坪水库坝壳料设计为天然级配砂（卵）砾石料，但由于前期设计及施工阶段一直存在河道人工采砂现象，因此砂砾石料场上层细颗粒缺失，小于5 mm的细颗粒含量变化范围为2%～26%，与天然级配砂砾石料相比在级配曲线、物理力学性质等方面发生了不同程度的变化，其人工扰动料占料场总储量的80%，这种筑坝材料的力学特性、压实特性、施工工艺及控制标准成为影响大坝填筑的关键因素，如按照传统观念，需更换砂砾石料料场或对扰动料采取工程措施进行处理。……