一种现场测定地基固结系数与渗透系数的方法

地基固结系数及渗透系数是地基计算及设计中的关键参数。本文利用IFCOBAT系统测试地基原位水平固结系数和渗透系数,采用考虑塑性区内外孔压系数不同的圆柱形孔洞扩张理论和一维径向固结方程模拟滤头周围的初始超静孔隙水压力分布及其消散过程,在渗透系数分析中,同时考虑了针头对流经水的阻力和滤头及容器内水柱的影响。现场测试结果与薄壁土样的室内试验结果的比较分析表明,现场测定的固结系数和渗透系数与室内试验结果接近。另外,还讨论了两种测试结果之间差别的原因及其合理性。

A method for in-situ testing of coefficients of consolidation and permeability of soils

Coefficients of consolidation and permeability are key parameters in the calculation and design of foundations. IFCO BAT-System was used to estimate coefficients of consolidation and permeability for soils in this study.Theorie s of cylindric al cavity expansion with different pore-pressure parameters inside and outside of the p lastic zone and one-dimensional consolidation, were applied to simulate distrib ut ion and dissipation of initial excess pore pressure around the filter tip. Flow characteristics of needle and water columns of filter tip and container were bot h considered in the analysis of coefficient of permeability.The comparison sho ws t hat in-situ results are close to laboratory values of samples taken with thin-wall sampler. In addi tion, the cause for the difference between in-situ results and laboratory valu es and its rationality were discussed.