饱和粉质黏土地基地下结构浮力折减系数

Buoyancy Reduction Coefficient of Underground Structure in Saturated Silty Clay Foundation

由于对饱和粉质黏土地基的浮力折减系数存在很大的争议,采用一套渗流路径完整、能够消除侧壁摩阻力及基底负压力并且可以准确判断内箱起浮瞬间的浮力测量系统,对粉质黏土中的模型箱底部总压力以及孔隙水压力进行测试,得到其折减系数为0.744。采用数值模拟软件COMSOL Multiphysics模拟得到的粉质黏土折减系数为0.754,与实验结果相差无几。运用线性回归方法建立粉质黏土折减系数的三元线性回归方程,对方程中自变量进行共线性诊断,剔除自变量中干密度与孔隙率,最终确定红砂岩和粉质黏土折减系数只与渗透系数有关。

There is a great controversy about the buoyancy reduction coefficient of saturated silty clay foundation.Thus,a buoyancy measurement system was adopted then.It could eliminate side wall friction and base negative pressure and accurately judge floating moment of the inner box.The system was with complete seepage path.The total pressure at the bottom of the box and the pore water pressure in the silty clay was tested.The results show that its reduction factor is 0.744.By the numerical simulation software COMSOL Multiphysics,the reduction coefficient for silty clay is 0.754,which is not much difference from experimental results.The ternary linear regression equation of the reduction coefficient of silty clay was established.The independent variables in equations were diagnosed as collinearity by linear regression method.And the dry density and porosity of the independent variables were eliminated.Finally,the reduction coefficient of red sandstone and silty clay was identified related to permeability coefficient only.