摘要
高压缩性软土具有典型的几何非线性和材料非线性特征,但目前能考虑井阻随时空同时变化的高压缩性土竖井地基大应变非线性固结解答还很鲜见。考虑土体的非线性压缩渗透特征,引入随时间和深度同时变化的变井阻模型,在拉格朗日坐标系下建立以超静孔压为变量的竖井地基大应变非线性固结模型。利用有限差分法获得模型的数值解答,并将其与特殊情况下竖井地基小应变解析解及大应变固结解对比分析以验证其可靠性。不同工况下竖井地基大应变固结性状分析表明:井阻随时空演化的变井阻效应会明显降低竖井地基的固结速率,且井阻的时间效应对固结速率的影响更明显,但变井阻效应并不会影响竖井地基的最终沉降量;初始有效应力均匀分布下的竖井地基固结速率相比其随深度线性增加时较慢,且2种情况下的竖井地基最终沉降值一般不再相等,沉降曲线间的差异也较大;任意深度处井周流入砂井的流量均相等的假定导致竖井地基固结速率偏快,使实际计算会过高估计竖井地基的固结速率;竖向渗流对地基固结的促进作用随竖井长度与竖井影响区半径之比的增大而减小。
The soft soil with high compressibility has typical geometric and material nonlinearities.However,the solutions for the large strain consolidation of soils with vertical drain,in which the time-and depth-dependent well resistance are considered,are rarely reported in the literature.Considering the nonlinear compressibility and permeability,and the time-and depth-dependent well resistance,a large-strain nonlinear consolidation model of soils with vertical drain is established in the Lagrangian coordinate system,in which the excess pore water pressure serves as a variable.The numerical solution for this consolidation model is derived by the finite difference method.The numerical results are compared with the existing small-strain analytical solution and large-strain numerical solution for the vertical drain ground to verify the correctness of the presented method.Then,the consolidation behavior analysis of the large-strain consolidation of soils with vertical drains under different conditions is performed,and the results show that the space-time variation of well resistance significantly reduces the consolidation rate.The time-dependent well resistance has a greatly impact on the consolidation rate.However,the final settlement of vertical drain ground can not be affected by the time-and depth-dependent well resistance.The consolidation rate under the uniform distribution of initial effective stress is less than that under the linear distribution.The final settlement values of the vertical drain ground in the two cases are not equal,and the differences between the two settlement curves are greatly large.The assumption that the discharge capacity flowing into the vertical drain at any depth are constant results in the faster consolidation rate,and overestimates the actual consolidation rate of the vertical drain.The promotion effect of vertical flow on the consolidation of vertical drain decreases as the ratio of the length to the influential radius of drains increasing.
作者
李阔
李传勋
LI Kuo;LI Chuanxun(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang,Jiangsu 212013,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2023年第S01期3743-3754,共12页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金资助项目(51878320)
关键词
土力学
竖井地基
大应变理论
井阻效应
非线性固结
竖向渗流
soil mechanics
soils with vertical drain
large-strain consolidation
effects of well resistance
nonlinear consolidation
vertical flow
