饱和成层土中静压桩挤土位移的模型试验研究  

Experimental study on squeezing displacement model for jacked piles in saturated layered soils

作　　者：孙晓东 鹿群[2] 杨永玉 

机构地区：[1]大地工程开发(集团)有限公司,北京100102 [2]天津城市建设学院,天津300384

出　　处：《工程勘察》2012年第2期5-10,共6页Geotechnical Investigation & Surveying

基　　金：天津市自然科学基金(09JCYBJC07800)

摘　　要：通过在饱和成层土中依次静力贯入三根桩的模型试验,研究了沉桩的挤土效应,总结了沉桩过程中土体在水平方向和竖直方向的位移变化规律,并对压入单桩、双桩和三桩的试验结果进行了对比分析。结果表明:沉桩过程中软硬土层交界处土体水平位移变化剧烈,呈波浪形分布,距桩越近水平位移变化越大;地表隆起最大值大约发生在距桩轴线2d(d为桩径)处;较硬土层对上部软土有约束作用而对下部软土有挤压拖带作用;双桩和三桩沉桩过程中已压入桩的"遮幕"作用明显;土体被挤压后,外摩擦角有所增大;桩周土体密度提高,影响范围大约在6d左右;上部土体含水量增大,下部土体含水量减小,但变化值不大。Based on the model tests in which three piles are pressed into the layered soils in sequence, the effects of squeezing against soils are studied. The laws of the soil displacements changing with the horizontal distances and depths during the process of pressing piles are obtained, and the testing results of pressing one pile, two or three piles are also compared and analyzed respectively. The results show that there is the rapid change of horizontal displacement which takes on the wave-shaped distribution at the boundary of soft soil and hard soil. The maximum vertical displacement occurs at about 2d （d is pile diameter） away from the axis of pile. The hard soil layer not only constrains the upper soft soil but also squeezes and tows the lower soft soil. There is the obvious ＂sheltering effect＂ of the existent pile when the second or third pile is penetrated. After the piles are penetrated, the angle of external friction and density of the soil around the piles have increased, and the affecting scope is about 6d. The water content of the upper soil increases and that of the lower soil decreases, but the varied values are low.

关 键 词：成层土 静压桩 模型试验 挤土效应 

分 类 号：TU443[建筑科学—岩土工程]