考虑复杂荷载及井阻非线性时竖井地基固结解析解研究

Consolidation properties for vertical drain under complicated loads and nonlinear well resistance

根据浙江沿海地区滩涂围垦中的淤泥基础海堤工程设计经验,认为软土工程中竖井地基固结计算需考虑井阻随时间的影响,基于竖井渗透系数随时间指数衰减关系假定,利用竖井地基径向固结理论和等应变假设,并考虑多级线性加载及循环荷载等复杂荷载作用,重新推导了考虑井阻非线性影响下竖井地基固结解析解,通过与TANG X W等(2000)、Zhu G等(2004)恒定井阻地基固结理论的对比,验证了本文理论的正确性。根据本文理论,通过对比分析,认为线性加载时间越长,竖井地基前期固结速率越慢,与骤加恒载工况差异越显著。在循环荷载作用下,地基固结速率一般介于荷载最大值和荷载最小值的恒载情况之间;且固结度随外荷载的波动而相应地滞后性震荡,竖井渗透系数衰减越快,其震荡越明显,最终趋向于稳定震荡。

Based on the experience of Zhejiang coastal beach reclamation projects, consolidation for vertical drain is considered in the calculation of the non-linear well resistance over time in soft foundation treatment. Based on the equal strain assumption and non-linear well resistance over time, the analytical solution for vertical drain is derived under the multistep linear loads and cyclic loads. The correctness of the present theory is verified by comparing with the existing theory of TANG X W, etc. （2000）, Zhu et al. （2004） under constant well resistance. According to this paper, the longer the time of linear load, the slower the calculation rate of the foundation with vertical drain, and the more significant the difference with the constant load conditions. At the same time, the permeability coefficient of vertical drain with time decays faster, and the consolidation speed is slower. Under the cyclic loading, ground consolidation rate is generally between the maximum load and the minimum load, and the degree of consolidation is shocking with the external load. The permeability of vertical drain decays faster, and the consolidation degree rebounds more obviously. Ultimately the shock tends to stable.