井阻对砂井地基固结作用的影响

Influence of Drain Resistance on Consolidation of Sand Drain Foundation

针对不同渗透系数、不同深度及不同半径砂井的地基,分别进行了砂井地基有限元固结计算,将考虑井阻作用的砂井地基固结有限元模拟结果与巴隆理想井固结解进行对比,分析井阻作用对砂井地基固结的影响程度,论证了砂井或排水板地基设计时适当考虑井阻或排水能力的必要性。研究表明:(1)砂井的渗透系数越小,相同时间条件下砂井地基所达到的平均固结度越小;同样,相同固结度条件下所需的固结时间越长,即井阻作用越明显;砂井处理的土层深度越大,井阻作用的影响也更为显著;(2)井阻作用对地基固结度及固结时间的影响不可忽视,在有限元模拟参数条件下,对应相同固结时间,当理想井固结度达到80%时,考虑井阻情况的固结度为13%~67%,相对于理想井固结度的相对误差16%~83%;对应相同固结度,当固结度达到80%时,考虑井阻情况相对于理想井的固结时间相对误差均大于50%。

For the foundations of sand drains with different permeability coefficients,different depths and different radii,the finite element consolidation calculation of the sand drain foundation was carried out. The finite element simulation results of the consolidation of the sand drain foundation considering the drain resistance are compared with the ideal solution of the Barron ideal drain. The influence degree of drain resistance on the consolidation of sand drain foundation was analyzed,and the necessity of properly considering drain resistance or drainage capacity when designing sand drain or drainage board foundation was demonstrated.The research shows that,(1) The smaller the permeability coefficient of the sand drain is,the smaller the degree of consolidation achieved under the same time conditions will be;similarly,the longer the time required for the same consolidation degree is,the more obvious the drain resistance effect will become. And the deeper the soil reinforcement is,the more significant influence of the drain resistance effect will be;(2)The influence of drain resistance on the consolidation degree of foundation and the consolidation time of foundation can not be ignored. Under the finite element simulation parameters of this paper,corresponding to the same consolidation time,when the ideal drain consolidation degree reaches 80%,the consolidation degree considering the drain resistance is 13% ~ 67%,and the relative error relative to the ideal drain consolidation degree is 16% ~ 83%. Corresponding to the same degree of consolidation,when the degree of consolidation reaches 80%,the relative error of the consolidation time relative to the ideal drain is greater than 50%.