高能冲击作用下淤泥水柱效应试验研究

针对笔者早期提出的静动力排水固结法处理高含水量饱和软黏土时存在水柱效应问题,利用多向高能电磁力冲击试验系统,对珠三角的淤泥进行高冲击能静动力排水固结室内模型试验,获得了淤泥力学响应相关规律: (1)土层中部与下部位置之间土压增量差值十分相近,孔压增量之间、土层压缩量之间亦有类似规律,初次验证了水柱效应的存在,即沿地基深度方向因瞬时不可压缩的水柱特性而可将相当部分夯击力传递至地基深处;(2)随着夯击遍数增加,冲击产生的附加应力与土自重比值逐渐增大,有效加固深度相应增加,夯击能可有效传递至地基土体深部。结果表明,当土中设置了竖向排水体系,不但有利排水,而且具有水柱效应,夯击时近似不可压缩的水柱可将冲击能量传递至地基深部软土中,使深层土体较充分排水固结。

Experimental Study on Water Column Effect of Muck Soil under High Energy Impact

A static-dynamic drainage consolidation library model test was conducted on the muck soil of Pearl River Delta,using the multi-directional high energy electromagnetic force impact test system,to verify the water column effect presented by the first author early.Some relative laws of mechanical responses are obtained as follow:(1) soil pressure increment difference between the middle and lower position of soil is very small,and both the pore pressure increment and the soil compression have similar phenomenon;it is the first time to verify the presence of water column effects,namely a considerable part of tamping force could be transmitted to the deep of foundation due to the transient incompressible characteristics of water column;(2) with the increase of tamping,the ratio of additional stress generated by tamping to soil weight increased gradually,and effective reinforcement depth correspondingly increased,and tamping energy can be effectively transferred to the deep soil.The results show that when a vertical drainage system is set up in soil,it is not only beneficial to drainage,but also has the water column effect;when tamping,nearly incompressible water column can transfer impact energy to the deep soft soil in foundation,and make deep soil drainage and consolidated fully.