应力变化的真空-堆载预压下竖井地基固结分析

Analysis of Vertical Drain Consolidation under Vacuum-Surcharge Preloading with Considering the Stress Variation

考虑真空度沿竖井线性减小、堆载所引起的附加应力随深度变化以及地基涂抹区水平渗透系数呈线性变化,推导了附加应力变化的真空-堆载预压下竖井地基固度的一个解析解,并分析了地基固结性状。分析结果表明,在荷载瞬时施加时,真空预压的大小及沿竖井的衰减快慢对地基的固结速度没有影响;在单面排水条件下,竖井地基顶面的附加压力越大,固结越快;在地基井径比和水平渗透系数与竖向渗透系数之比较小时,地基的竖向渗流对地基的固结度有较大的影响。

An analytical solution is obtained for the consolidation of vertical sand foundation under vacuum preloading considering simultaneously the variation of vacuum degree, the variation of stress increment with depth, both horizontal and vertical drainage, and the linear distribution pattern of horizontal permeability coefficient of soil was also considered. Furthermore, the consolidation behavior of vertical drain foundation is analyzed. The results show that if the loading is applied instantaneously, the consolidation degrees of foundation would not influenced by vacuum degree. Under single-drainage condition, the larger the stress on the top of the foundation, the faster the consolidation would be. Furthermore, the less the radius ratio is, and the less the ratio of horizontal permeability to vertical permeability is, the greater the under-estimated value will be.