水泥土搅拌法加固斜坡软弱土地基的土工离心模型试验研究  

The Geotechnical Centrifuge Model Experiment Study of the Slope Soft-Soil Foundation Improved by Cement Soil Mixing Method

作　　者：罗强[1] 胡勇刚[1] 张良[1] 杨尧[1] 

机构地区：[1]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《中国铁道科学》2010年第4期12-19,共8页China Railway Science

基　　金：铁道部科技研究开发计划项目(2007G012);西南交通大学创新团队培育计划项目(2007IRT06)

摘　　要：以达成铁路扩能改造工程新建段某工点为原型,设计5组基于水泥土搅拌法地基处理方案的室内土工离心模型试验,分析在路堤荷载作用下水泥土搅拌法不同布桩方式对斜坡软弱土地基的加固效果和对桩土荷载分担及加筋垫层筋带拉力的影响规律。分析表明:斜坡软弱土地基在构造上存在的不均匀性对路堤基底压力分布和桩土荷载分担等力学响应有明显影响,并随下坡一侧软弱土层厚度的增加会产生一定的卸载效应和桩土间压力调整加剧的现象;采用"上疏下密"不等间距的布桩模式,可调整桩土压力的分布,更好地适应地基软弱土层厚度的变化,提高地基加固的均匀性;加筋垫层筋带拉力受路堤荷载、软弱土层厚度和桩布置间距等因素的共同影响,分布形态表现出明显的非对称特点,最大值出现部位与斜坡软弱土地基可能产生的变形破坏位置有很好的一致性。This essay takes a research site of the capacity expansion and conversion project from Dazhou to Chengdu as the prototype,designing 5 groups of indoor geotechnical centrifuge model tests based on the foundation treatment of the cement soil mixing method,and analyzing the strengthening effect of different piles layout under loads of embankment and the influence about the pile-soil load-sharing and the pulling force of the reinforced cushion geogrid. Analysis shows that the non-uniformity of the slope soft-soil foundation in structure affects significantly on the foundation＇s mechanical response,such as the pressure distribution and load-sharing. Unloading effect and the adjustment of pile-soil load-sharing may occur with the increasing depth. The use of the varying pile spacing mode can adjust the distribution of pile-soil pressure,and better adapt to the change of the thickness of the soft-soil foundation and improve the uniformity of foundation strengthening. The pulling force of the reinforced cushion geogrid is affected by many factors,for instance the embankment loading,the thickness of soft-soil foundation and the pile spacing arrangement. Its distribution pattern has significant feature of the asymmetry. There is good consistency between the appearing position of the maximum value and the possible deformation location of the slope soft-soil foundation.

关 键 词：地基加固 斜坡软弱土地基 桩土荷载分担比 垫层筋带拉力 土工离心模型 水泥土搅拌法 

分 类 号：U213.15[交通运输工程—道路与铁道工程] TU471.8[建筑科学—结构工程]