泥炭质土层劲性复合桩承载性能试验研究

Experimental study on bearing capacity of stiff composite pile in peat soil

泥炭质土作为云南地区特有的土质,是一种特殊的软土地基,这使得对于桩基的选择成为重中之重。劲性复合桩是一种利用水泥土桩内部插入相应芯桩组合而成的新桩型,对承载性能有很大提升,并且对软土地基处理有良好的效果。本文通过室内模型试验与Midas GTS NX有限元数值分析,研究不同芯桩长度及不同截面大小的劲性复合桩的荷载-沉降关系。试验表明,劲性复合桩在泥炭质土层中具有大直径桩的特性,荷载-沉降曲线均呈“缓降”型;芯桩承担主要荷载,芯桩扩大12%面积,沉降位移下降8%左右,芯桩长度增加33%,沉降位移减少20%左右。

Peat soil is a special soft soil foundation in Yunnan,which makes the choice of pile foundation become the top priority.Stiff composite pile is a new type of pile which is composed of cement-soil pile and corresponding core pile.It greatly improves the bearing capacity and has good effect on soft soil foundation.In this paper,through indoor model test and Midas GTS NX finite element numerical analysis,the load-settlement relationship of stiff composite piles with different core pile lengths and different section sizes is studied.The test results show that the stiff composite pile has the characteristics of large diameter pile in peat soil layer,and the load-settlement curves show a slow drop trend.The core pile bears the main load.The settlement displacement decreases by about 8% when the core pile expands by 12%,and the settlement displacement decreases by about 20% when the core pile length increases by 33%.