降水对软黏土渗流特性影响的试验研究

在降水后的上海地铁10号线同济大学站基坑工程现场取样,进行不同固结压力下的室内渗透试验,分析了工程降水对上海软黏土渗流特性的影响.忽略土样自重应力,假设土样垂直总应力等于固结压力,孔隙水压力为静止水压力,将垂直渗透系数与固结压力之间的对应关系转化为垂直渗透系数和垂直有效应力间的对应关系,用数学公式描述垂直渗透系数与垂直有效应力之间的数值关系.结果表明,降水作用使上海软黏土渗流特性的各向异性愈加明显,垂直渗透系数的对数与垂直有效应力成线性关系.

Effect of Dewatering on Soft Clay's Seepage Characteristics

Through an excavation site sampling of Tongji University station in Shanghai metro line 10 after dewatering and a laboratory penetration test under different consolidation pressures,the influence that engineering dewatering exerts on shanghai soft clay’s seepage characteristics is analyzed in this paper from theoretical and experimental perspective.Ignoring the soil self-weight stress and assuming that vertical total stress of soil samples is equal to consolidation pressure and the pore water pressure is static,this experiment converts the correspondence between vertical permeability coefficient and consolidation pressure to the correspondence between vertical permeability coefficient and vertical effective stress,then the numerical relation between vertical permeability coefficient and vertical effective stress is described with a mathematical formula.The result shows that dewatering makes the anisotropy of Shanghai soft clay seepage characteristics more obvious and there is a linear relationship between the vertical permeability coefficient’s logarithm and the vertical effective stress.