考虑固结的基坑开挖回弹问题有限层求解

Finite layer analysis for excavation rebound considering consolidation

在综述前人有关基坑变形研究成果的基础上,指出开挖回弹量直接影响到基坑的稳定性和建筑物的后期沉降,但相关研究很少考虑土体在开挖过程中的固结影响。现引入固结有限层法,通过增加开挖部分的耦合矩阵和开挖部分的渗透矩阵,建立三维横观各向同性土体考虑固结的开挖回弹问题的有限层求解格式,并编制了相应的计算程序,以分析开挖过程中坑底土体的动态固结过程和负孔压的消散规律,研究固结对坑底土体回弹的影响程度。结果表明坑底土体的孔压随时间逐步消散,从负孔压慢慢消散到零,且符合Mandel-Cryer效应,坑底的回弹量随时间不断增加,且中心点回弹量较大,边缘点回弹量相对较小,总体成中心对称的倒锅底形。

According to the former researches on deformation of foundation pit, it＇s known that the influence of rebound on stability of pit and post-settlement of construction is great. However, among the existing studies, the discussion on effect of consolidation on rebound is few. Therefore, the consolidation finite layer theory is introduced to analyze the dynamic process of soil consolidation during excavation and dissipation law of negative pore pressure with time. And the expression of finite layer method on excavation rebound considering consolidation is established by adding coupling matrix of excavated area and seepage matrix of excavated area. At the same time, the computer program is developed. The results show that negative pore pressure of bottom soil ranges from negative to zero, and it appears the Mandel-Cryer phenomena. While the rebound of bottom soil is increasing with time. And for whole excavated area, the distribution of rebound is similar to the shape of reverse hollowware.