土体水平渗透系数变化的多层砂井地基固结性状分析

CONSOLIDATION BEHAVIOR ANALYSIS OF MULTI-LAYERED SAND DRAINS FOUNDATION WITH VARYING HORIZONTAL PERMEABILITY COEFFICIENT

在考虑涂抹区土体水平渗透系数3种变化模式即水平渗透系数不变、呈线性变化和呈抛物线变化的情况下,对单面排水和双面排水条件下多层砂井地基的固结问题进行分析,推导出解析解,并对双层砂井地基的固结性状进行分析。结果表明,只有在各层土的压缩模量相同时,成层砂井地基按孔压定义的固结度才等于按变形定义的固结度,否则前者大于后者;当涂抹区水平渗透系数呈抛物线变化时地基固结最快,呈线性变化时次之,不变时最慢;施工扰动范围、程度越大,固结越慢;增大任何一层土的压缩系数,均可加快整个地基中的孔压消散。

The consolidation of multi-layered sand drains foundation under single-drainage condition and double- drainage condition was analyzed.Three types of variation patterns of the horizontal permeability of soil in the smear zone were considered,including the constant distribution pattern,the linear distribution pattern and the parabolic distribution pattern,and an analytical solution was obtained.The consolidation behavior of double-layered sand drains foundation was investigated.The results show that the overall average degrees of consolidation of foundation in terms of pore pressure is equal to that in terms of strain only if compression modulus of every layer is equal to each other,otherwise the former is always larger than the later;the consolidation rate is at its maximum for the parabolic distribution pattern and is at its minimum for the constant distribution pattern whereas the one for the linear distribution pattern is in the middle.The larger the smear zone is,the slower the consolidation rate is;the greater the disturbance magnitude is,the slower the consolidation rate is.Increasing compression modulus of any layer could accelerate the dissipation of pore pressure.