摘要
通过对在不同排水条件下的海相软土进行三轴剪切蠕变试验,研究上海海相软土的剪切蠕变特性和计算模型。试验结果表明:不排水时,在低应力水平(小于60%)下试样变形增量差异较小,应力水平达到一定时(大于80%)产生大量瞬时变形和蠕变变形,孔隙水压力经历了瞬时急剧上升后下降、然后再缓慢上升的过程,应力-应变关系为非线性;排水时,各级应力水平下产生的变形增量差别不大,孔隙水压力经历一段时间上升后持续下降,最后趋于稳定,孔隙水压力持续上升时间约10 min,应力-应变关系近似为线性;两种排水条件下的ε-lnt曲线均呈平行曲线。建议应力-应变关系采用幂函数表示、应变-时间关系采用双曲线型函数表示,以建立适用于不同排水条件下的软土蠕变方程。该模型能较好地描述应力水平不超过80%的不排水和排水条件下上海软土的三轴剪切蠕变行为。
The creep characteristics and model of Shanghai marine soft soil were studied by drained and undrained triaxial shear creep tests.In undrained condition,the incremental deformation difference of specimens was small at lower stress levels（〈60%）,and the instantaneous deformation and creep deformation were increased suddenly at higher stress level（〉80%）;and pore water pressure experienced an instantaneous sharp rising,falling,and then slowly rising;the stress-strain relationship was nonlinear.While in drained condition,the incremental deformation difference of specimens was not significant in all stress levels;and the pore water pressure was rising for 10 minutes,then declined,and finally to be stable;and the stress-strain relationship was linear.However,the ε-lnt curves were nearly to be parallel in undrained and drained conditions.The creep models of Shanghai soft soil were proposed for drained and undrained conditions,in which power function was adopted for stress-strain relationship and hyperbolic function for strain-time relationship.The model which stress level was below 80%,could be better to describe the triaxial shear creep behavior of Shanghai marine soft soil in different drainage conditions.
出处
《工业建筑》
CSCD
北大核心
2017年第12期26-30,共5页
Industrial Construction
基金
国家自然科学基金青年项目(41702323)
广西岩土力学与工程重点实验室(15-KF-04)
页岩气资源利用湖南省重点实验室(E21719)
湖南省教育厅科研项目(17C0648)
关键词
海相软土
三轴剪切
排水条件
孔隙水压力
蠕变模型
marine soft soil
triaxial shear
drainage condition
pore water pressure
creep model
