基于大变形的冲填土自重固结分析及离心模型试验

STUDY ON CONSOLIDATION SETTLEMENT OF DREDGER FILL UNDER DEADWEIGHT USING LARGE STRAIN THEORY AND CENTRIFUGE MODEL TEST

基于大变形理论和离心模型试验对上海临港新城地区冲填土自重固结沉降进行分析研究。研究结果表明:大变形理论计算和离心模型试验所得冲填土自重固结沉降量及最终固结时间基本一致,但在未完成固结之前,对于相同的固结度,理论计算的固结时间均明显大于试验所得时间;冲填土的自重固结过程包括快速和缓慢固结2个阶段,快速固结阶段大约需要1 a时间;在快速固结开始阶段,沉降很快,0.5 a的固结度可达50%,快速固结阶段的沉降量占最终沉降的80%,而缓慢固结阶段的沉降量只占最终沉降量的20%。通过对试验数据回归分析,得出冲填土的自重固结沉降与时间的关系式,利用该式可对冲填土地区沉降变形进行预测。

The consolidation settlement of the dredger fill under deadweight in Lingangxincheng area of Shanghai is studied using large strain theory and a centrifuge model test. The settlement and final time of consolidation under deadweight are achieved from large strain agrees with centrifuge model test. For the same degree of consolidation, the time of consolidation got from large strain theory is more than that got from centrifuge model test before consolidation of dredger fill is completed. The consolidation settlement under deadweight includes two stages： quick and slow consolidations. The quick consolidation takes about 1 year. At the initial stage of the quick consolidation, soil settles fast. Fifty percent of the settlement is completed after half a year. Eighty percent of the total settlement takes place during the quick consolidation. The remaining 20% of the settlement occurs during the slow settlement. An empirical formulation is determined through curve fitting to describe the relationship between settlement and time. The formulation can be used to predict the consolidation settlement of dredger fill.