变荷载作用下未打穿竖井地基固结分析

CONSOLIDATION OF GROUND WITH PARTIALLY PENETRATED VERTICALDRAINS UNDER TIME-DEPENDENT LOADING

利用已有瞬时荷载作用下未打穿竖井地基固结模型,根据线性偏微分方程的叠加原理,将变荷载作用问题分解为瞬时荷载作用问题,给出了变荷载作用下未打穿竖井地基固结解答。利用该求解方法,对一未打穿竖井地基在单级线性加载和多级加载情况下的孔压消散进行了分析。分析表明,受加载历时影响,竖井打设区平均固结度减小幅度大于下卧层,但下卧层受影响时间要长得多。另外,在粗略设计中,可以将多级加载简化为单级线性加载,这样对后期平均固结度的影响不大。

Existing consolidation model of ground with partially penetrated vertical drains under instantaneous loading is extended for time-dependent loading. Based on the principle of superposition in linear partial differential equations, the solutions for the consolidation of ground with partially penetrated vertical drains under time-dependent loading are developed by decomposing time-dependent loading into instantaneous loading. Using the solution method mentioned above, pore pressure dissipation of a soft ground with partially penetrated vertical drains under single ramp loading and multi-ramp loading is analyzed. It is shown that, under the effect of loading time, the scope of average consolidation degree of the section with vertical drain is greater than that of the section without it, but the latter lasts much longer. It also shows that multi-ramp loading can be replaced by a single ramp loading in preliminary design, which has less effect on average consolidation degree when time is comparatively long.