砂井地基固结过程的监测与分析

来源期刊：中南大学学报(自然科学版)2004年第6期

论文作者：魏丽敏 何群 孙愚男

文章页码：1019 - 1024

关键词：砂井地基; Biot固结理论;非线性弹性;沉降;孔隙水压力

Key words：sand drain ground; Biot s consolidation theory; nonlinearity elastic model; settlement; porewater pressure

摘    要：采用沉降板、分层沉降仪、孔隙水压力计等仪器,对路基分层填筑过程中砂井地基的固结规律进行监测,保证路基的安全填筑。将非线性弹性本构关系引入Biot固结理论有限元程序,把砂井地基等效为砂墙,采用中点增量法研究施工过程中地基沉降与孔隙水压力消散的规律,其计算参数由室内三轴试验确定。研究结果表明:采用非线性弹性模型计算的孔隙水压力峰值和沉降量均大于弹性模型计算值,能模拟在分级加载过程中砂井地基的沉降和孔隙水压力消散的规律;泊松比对非线性模型的孔压变化趋势影响不大,但沉降量随泊松比的增大而减小;只有当渗透系数发生数量级改变时,才引起孔压的明显变化。

Abstract: The consolidation behavior of the sand drain ground during the process of filling the embankment was monitored by the settlement plate, telescoping tube settlement gauge and pore water pressure cell. Non-linear consolidation analysis using a finite element formulation based on Biot’s consolidation theory was used to study the behavior of the settlement and the pore pressure dissipation in the sand drain ground, which was converted to be sand wall. The midpoint increment method was used and the calculation parameter came from the consolidated-drained triaxial compression tests. The calculated settlement and pore water pressure were presented and compared with the situ values. The results show that both the peak of the pore pressure and the settlement calculated by nonlinearity elastic model are bigger than that of linearity elastic model, and the nonlinearity elastic model can simulate the behavior of the settlement and the pore pressure dissipation more exactly during the step loading process. The sensitivity analysis of parameter shows that the Poisson’s ratio has little effect on the developing of the porewater pressure, the settlement decreases with the increase of the Poisson’s ratio. The pore water pressure changes observably only when the coefficient of permeability has decuple changes.