考虑涂抹作用的未打穿砂井地基固结理论分析

 在等应变假设和瞬时加载条件下，研究单面和双面排水情况下未打穿砂井地基的固结问题。通过设置虚拟砂井的方法考虑未打穿土层的径竖向组合渗流；同时，为考虑施工对土体的扰动随离砂井的距离增大而逐渐减小的事实，引入一个函数，将土体水平渗透系数统一表达，并在假设的3种模式下(涂抹区水平渗透系数不变、呈线性变化和呈抛物线变化)，得到未打穿砂井地基固结解析解。编制计算程序，详细阐述编程过程中要注意的几个问题，对未打穿砂井地基的固结性状进行分析。结果表明，考虑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；砂井打入深度越深，固结越快；砂井渗透系数越大，固结越快。

THEORETICAL ANALYSIS OF PARTIALLY PENETRATED SAND DRAINS FOUNDATION IN CONSIDERATION OF SMEAR EFFECT

Under equal strain assumption and instantaneous loading condition,the consolidation of soft soil with partially penetrated vertical drains under single-drainage condition and double-drainage condition is studied. Vertical and radial seepages of soils under sand drains are considered through setting suppositional sand drains. Meanwhile,in order to consider the fact that the larger the distance from sand drain is,the lighter the disturbance of construction is,the horizontal permeability of soils is expressed in unified way through introducing a function. Three types of variation patterns of the horizontal permeability of soil in the disturbed soil zone are considered,including the constant distribution pattern,the linear distribution pattern and the parabolic distribution pattern,and an analytical solution is obtained. Corresponding computer program is developed and several problems that should pay attention to during the process of programming are expounded;then the consolidation behavior of partially penetrated sand drains foundation is investigated. The results show that the consolidation is the fastest if the parabolic distribution pattern is considered;the consolidation is slower if the linear distribution pattern is considered;the consolidation is slowest if the constant distribution is considered;and that the larger the disturbance zone is;the slower the consolidation is;the greater the disturbance is,the slower the consolidation is;the deeper the sand drains is,the faster the consolidation is;the larger the permeability coefficient of sand drains is,the faster the consolidation is.