淤泥质软土在冲击荷载作用下孔压增长模式

Pore water pressure mode of oozy soft clay under impact loading

通过室内淤泥质饱和软粘土的动力固结试验,考虑不同锤重和落距组合情况,对冲击荷载作用下饱和软粘土孔隙水压力的动态响应特征进行分析。试验结果表明,孔隙水压力和冲击击数之间是双曲线对应关系,高围压下冲击荷载激发的孔压随击数增长的速率快,超固结软土在冲击过程中孔压出现了负值。冲击荷载对土体产生的附加应力能导致孔压上升,孔压消散使得土体内有效应力增加,强度提高。对强夯施工中以孔压控制施工质量具有指导性意义。

Based on the laboratory dynamic consolidation tests of saturated oozy soft clay under impact loading, the dynamic response characteristics of pore water pressure were analyzed. The tests considered different combination schemes between hammer weight and dropping height. The relationship between pore water pressure and impact times followed the hyperbola. The rate of increase of pore water pressure is faster with impact number under high confining pressure; and for the pore water pressure of over consolidation soft clay under impact loading, the negative value occurred. The subsidiary stress of impact loading causes the increasing of pore water pressure; and the effective stress is increased because of the dissipating of pore water pressure. It is highly important to control construction quality by monitoring pore water pressure during on-site dynamic consolidation.