覆盖层上混凝土-堆石混合坝模型试验研究

Experimental studies of concrete-rockfill combination dam on alluvium deposit

混凝土-堆石混合坝由混凝土墙、堆石以及之间的垫层和过渡层组合而成,作为一种新型结构,目前针对其受力机制及变形特性的研究较少。基于此,开展覆盖层上混凝土-堆石混合坝模型试验研究,测得填筑和蓄水期不同高度处墙体的土压力和位移,探讨混合坝的工作机制,最后根据模型试验结果提出了考虑墙体位移的修正土压力计算公式。研究结果表明:在填筑期,堆石处于主动极限状态和静止状态之间,混凝土墙受到的堆石压力较小;蓄水后,堆石接近静止状态,混凝土墙受到的堆石压力比填筑结束时刻增加了一倍左右;修正土压力公式能够较好地反映混合坝在填筑期和蓄水期土压力随墙体位移变化的规律;混凝土墙的抗滑安全系数最小值出现在填筑结束时刻,满足相关要求,说明混合坝对覆盖层有较好的适应性。

Concrete-rockfill combination dam（CRC dam） is composed of concrete wall, rockfill, cushion layer and transition layer. As a new structural pattern, its stress and deformation characteristics are not studied thoroughly. For this reason, a model test is carried out to measure the earth pressure and displacement of CRC dam on alluvium deposit at different heights and to explore the performance of CRC dam in filling and impoundment stage. Then a modified calculation method of earth pressure considering the displacement is proposed. The test result shows that： the rockfill is close to active state at the end of dam filling construction, the earth pressure on the concrete wall is relatively low, while the rockfill is close to static state under the water pressure at the end of impoundment stage, the earth pressure on the concrete wall is approximately one time higher than that of the filling stage. The modified formula well reflects the change rule of the earth pressure with wall displacement during filling and impoundment stage. The minimum of sliding safety factor（SSF） occurs at the end of dam filling period and meets the relevant requirements. The test proves that the CRC dam has good adaptability to alluvium deposit.