摘要
针对应用冻结工法维护大型深基坑工程中冻土墙与内衬相互作用规律的研究难题,利用有限元数值模拟技术,分别建立弹塑性和蠕变模型来模拟基坑开挖卸载瞬时以及段高暴露后的冻土墙和内衬结构相互作用的规律。不考虑冻土蠕变特性的弹塑性模型的计算表明,开挖卸载后应力释放是冻土墙瞬时变形的主要因素,此时冻土墙位移分布同开挖段高关系不是十分明显,二者相互作用主要表现为内衬结构对冻土墙变形的约束作用;而开挖段高暴露后冻土蠕变是产生冻土墙后续变形的重要原因,此时冻土墙的位移和受力同开挖段高、暴露时间等施工工艺密切相关。在实际工程中,必须考虑冻土蠕变特性,优化施工工艺,实行小段高快速掘进,以控制蠕变位移的增长,减小冻土墙和内衬结构的受力。
The study on the interaction laws between the frozen soil wall and its supporting structure is of great importance in the deep excavation. The difficulties in the application of the ground freezing method to deep excavation are presented firstly. The interaction laws between the frozen soil wall and its supporting structure after excavation and during creep period are obtained with numerical simulation elasto plastic and creep models. The results of elasto plastic model,without considering the creep properties of frozen soil,indicate that the release of loading by excavation is the major factor that leads to the deformation of the frozen soil wall and the liner. In this case the distributions of displacements are not closely related to excavation height,and the supporting structure has an appreciable restricting role,which prevents the frozen wall from displacing and rotating freely. However,during the creep period,besides the effect of the excavation,the creep characteristics of frozen soil,the exposed time and height have strong effects on the distributions of the stresses and displacements,which has been shown by the creep models. Therefore,it is suggested that all these factors should be comprehensively taken into consideration in engineering practice.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2004年第13期2286-2291,共6页
Chinese Journal of Rock Mechanics and Engineering
关键词
岩土力学
深基坑
冻土墙
数值模拟
弹塑性
rock and soil mechanics,deep excavation,frozen soil wall,numerical simulation, interaction
