基于模型试验的群桩沉桩挤土效应微结构分析  

Analysis of microstructure of soil compacting effect in pile group based on model tests

作　　者：张建新[1] 孙世光[1] 张淑朝[1] 鹿群[1] 

机构地区：[1]天津城市建设学院天津市软土特性与工程环境重点实验室,天津300384

出　　处：《辽宁工程技术大学学报（自然科学版）》2009年第1期63-65,共3页Journal of Liaoning Technical University (Natural Science)

基　　金：天津市自然科学基金资助项目(06YFJMJC05700);天津市教委科研资助项目(20071002)

摘　　要：基于静压群桩模型试验,运用扫描电镜获取了压桩前后土样的微观结构照片,并运用图象处理技术提取了群桩沉桩前后不同位置处土体微观结构参数,通过对比分析认识到:沉桩前桩周土体结构疏松,孔隙形状不规则,群桩压入后桩群中土体孔隙明显减小,孔隙的方向性增强;群桩压入后,等效直径、平面孔隙率、孔隙周长在地表及一定深度内都有所减小;孔隙个数增多,有土体被挤密的现象,而且随着深度的增加这种挤密效果更加明显;压桩后土颗粒的圆度和形态比变大,颗粒在几何形态上向扁长方向发展,且孔隙定向性集中于一到两个方向。Based on model tests of the static pressed pile groups, the soil sample＇s microstructure pictures are acquired by the electronic scanning microscopy before and after pile driving. The parameters of the microstructure mechanism of soil are obtained by the image manipulation techniques. Through contrasting and analyzing, it is realized the structure of the soil is loose before pile driving, the figure of the pore is irregular, the size of pore in soil gets smaller after the pile group are driven, the directivity of pores gather. Equivalent diameter, the plane porosity and circumference of pores decrease from the ground surface to a certain depth below. The increasing number of pores results in the compacting phenomenon of the soil, and the compacting effect is more obvious along with the increase of the depth. After the pile being driven, the roundness and shape ratio of soil particles are enlarged, the geometry shape of particles develops to flat and long, and the directivity of the pore focus in one to two directions.

关 键 词：群桩 挤土效应 模型试验 微观结构 

分 类 号：TU473[建筑科学—结构工程]