高压注浆加固造成铁路路基隆起的原因分析

高压旋喷法施工造成路基、地面抬升,是地基处理过程中较常见的现象。分析上海地铁9号线高压旋喷施工造成铁路路基隆起的工程实例,将路基变形过程和注水试验进行对比,得出了注浆过程满足土体注水膨胀原理;同时由于桩周产生的压力远大于土体所能承受的孔隙水压力,使破坏的土体挤压进路基底部,加大了隆起量。通过调整施工参数,可改变土体注水膨胀的本构定律与桩周压力公式中相关变量,从而减小隆起量;并提出了调整施工进度、工艺等相应的处理方案。

Analysis of railway groundwork upwarping caused by jet grouting in high pressure

Uplift of the groundwork and land surface in high pressure jet grouting is a commonplace in engineering constructions.Analyzing the uplfting in high pressure jet grouting in the construction of the subway No.9 in Shanghai as an example,with monitoring the groundwork deformation or dilation process with water injection test,the authors found out that the correlations between grout injection and the soil mass deformation,especially,the mechanism how grout injection process can match the deformation without causing the foundation uplifting.In fact,the pressure around pile wall is far much higher than the maximum pore water pressure at which soil mass can hold,thus broken soil mass are extruded into the lower groundwork,as a result,causing more upwarping.Through modifying the grouting parameters,the constitutive law of dilation by water injection and the correlation variables in the pressure formula established around pile wall could be changed so as to minimize the upwarping;finally,the new treatment schemes on grouting progress and techniques are presented.