振动沉管施工素砼桩挤土效应研究

Reaserch on Soil Squeezing Effect by Vibration Immersed Tube Construction

素砼桩复合地基是高速公路软土地基处理的常用方法;当其采用振动沉管法施工时,会有明显的挤土效应。通过广东省某高速试验段原位试验,对较小桩间距下不同施工方案桩体及土体在不同深度的水平位移量进行了测试和分析。结果表明:在素砼桩桩间距为1.2 m时,连续振动沉管施工成桩质量较差,不宜采用;而采用隔桩跳打施工时,桩体沿纵深方向不同深度水平位移量较小,桩体倾斜度满足设计要求;另外补桩施工时,周围桩体不同深度水平位移量明显小于土体位移量,桩身位移变化小,成桩质量良好。

Plain concrete pile is commonly used as the treatment of soft ground in highway construction. However,when the vibration sinking pipe concrete pile method is used,the compacting effect can not be neglected. The horizontal displacements of soil and piles at different depth under different construction schemes were tested and analyzed. The results showed that,with a pile space of 1. 2 m,when the piles were continuously constructed,the pile quality was poor. In contrast,staggered piling was found to be effective in reducing the compacting effects. In addition,the horizontal displacements of constructed piles were much smaller than those of soil at the same depth during the pile addition procedure in staggered pile scheme.