预制桩挤土效应对周边土层的影响分析

The extrusion effect analysis of precast pile construction on surrounding sold layer

徐州丰县地层在15m深度普遍存在一层密实状砂土,预制桩进入或穿透该层时难度较大,通过桩基施工前的标贯试验和桩基施工后的静力触探试验,结合相关规范原理,对预制桩施工过程中的挤密效应进行分析,发现预制桩在粉土、粉砂中沉桩时,超孔隙水压力消散较快,土体有效应力增大,再加上群桩的挤密作用,导致土的强度得到大幅提高,增加沉桩难度;提出相应沉桩对策,以减少对工程的不利影响,为该地区的桩基施工提供参考。

There is a layer of thick sand at the depth of fifteen meters in Fengxian County(Xuzhou City), when the precast pile enters this layer or penetrates this layer, it is very difficult. Through standard penetration experiment before the pile foundation construction and static cone penetration experiment after the pile foundation construction, this article analyzes the squeezing effect in the process of precast pile construction combined with the principles of relevant specifications, it is found that the excess pore water pressure dissipates quickly when precast piles driven in sandy soil,and the effective pressure of sandy soil improves, coupled with the squeezing effect of pile groups, the strength of sandy soil is greatly improved and the difficulty of pile sinking is improved. Finally, the article puts forward some corresponding pile sinking measures to reduce the adverse impact on the project, and provides some reference for the pile foundation construction methods in this area.