摘要
针对软土地层中压入式沉井的下沉稳定性控制问题,基于土塞形成机理推导出土塞高度的计算表达式,采用耦合欧拉-拉格朗日法(CEL)模拟沉井的动态压入过程,分析下沉中的土塞演化过程及土体应力、应变场,探讨土塞效应对沉井侧摩阻力和刃脚阻力的影响.结果表明:在软土地层中,土塞高度的计算表达式能够较准确地得到下沉时的井内土塞高度;沉井压入下沉时土塞效应逐渐增大,在下沉深度约为25 m时变化趋势放缓,土塞率(PLR)约为0.56,土塞增量填充率(IFR)约为0.41,土塞为不完全闭塞;土塞效应引起的井内土体水平和竖向应力激增及土体等效塑性应变主要集中于有效土塞高度范围内;土塞效应会使沉井侧摩阻力尤其是内壁侧摩阻力显著增大;土塞效应会使沉井刃脚阻力增大,尤其在软弱地层中最明显.
An analytical calculation formula of soil plug’s height was deduced based on the generating mechanism of soil plug in order to analyze the control of press-in caisson ’s sinking stability in soft ground. Then the coupled Eulerian-Lagrangian(CEL) method was used to simulate the sinking process of a press-in caisson. The influence of soil plugging effect on lateral friction force and blade feet resistance force was discussed based on the analysis of the developing process of soil plug and stress and strain field of soil. Results show that the analytical calculation formula can precisely predict the soil plug’s height in soft ground. The soil plugging effect gradually increases during the caisson’s press-in sinking procedure, but the pace of change slows down around the depth of 25 m. The plug length ratio(PLR) is about 0.56 at the end of sinking, and the incremental filling ratio(IFR) is about 0.41, which means that the soil plug is still incomplete occlusive. The increase in horizontal and vertical soil stress as well as the equivalent plastic strain caused by soil plugging effect mainly concentrated in the range of the effective soil plug’s height. Then the lateral friction force increases, but lateral friction force of inner wall grows more remarkable compared with outer wall. The blade feet resistance force increases owing to soil plugging effect, and the increase becomes significant especially in soft ground.
作者
易琼
廖少明
朱继文
徐伟忠
YI Qiong;LIAO Shao-ming;ZHU Ji-wen;XU Wei-zhong(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Shanghai Urban Construction Municipal Engineering(Group)Limited Company,Shanghai 200065,China)
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2020年第7期1380-1389,共10页
Journal of Zhejiang University：Engineering Science
基金
国家“973”重点基础研究发展规划资助项目(2015CB057806)
上海市科委资助项目(18DZ1205404)。
