考虑施工过程的深基础坑底土应力状态分析  

Study on Stress State of Soil in Deep Foundation Pit Considering Construction Process

作　　者：徐美娟[1] 宋林辉[2] 梅国雄[3] 

机构地区：[1]南京交通职业技术学院,南京211188 [2]南京工业大学力学部,南京210009 [3]南昌航空大学土木建筑学院,南昌330063

出　　处：《地下空间与工程学报》2012年第5期958-962,968,共6页Chinese Journal of Underground Space and Engineering

基　　金：国家自然科学基金(50608038);霍英东青年教师基金(91076);江苏省"六大人才高峰"项目(06-F-014)

摘　　要：与其他材料不同,土体的力学性能分析必须建立在其所处应力状态的基础上进行。基于这一思想,在对深基础进行变形分析时,根据基础建设的施工工艺,将整个分析过程划分为施工前的准备工作、基坑降水、基坑开挖、结构施工和地下水位回升五个工况;同时为凸显问题核心,简化分析过程,假定每个工况中荷载的加、卸均瞬时发生,且基础为等补偿基础(结构荷重与挖除的土重相等)。在此基础上,详细分析五种工况中坑底土体所处的应力状态,并进行对比分析,计算出各工况下土体大、小主应力的增量变化,绘制出坑底土体经历的有效应力路径,指出在基础建造过程中,坑底土体将经历复杂的应力变化过程,对土体的强度和变形都将产生很大影响。The soil characteristics are different from those of other materials, the influence of stress state on me- chanical properties of soil is great. Therefore, the whole analysis process of deep foundation can be compartmentalized into five construction conditions. Those are preparation, precipitation, excavation, construction of superstructure and comeback of groundwater level respectively. In order to highlight the core of the problem and simplify the analysis process, the loading and unloading for each analysis process are assumed to be instantaneous. It is worth emphasizing that the subject is compensation foundation, where the structural loading and excavated soil weight are equivalent. Then, the states of stress of all construction conditions are listed. The effect stress path is protracted according to the states of stress. Therefore, the bottom soil will experience a complex stress changes during the building processes, which will have a significant impact on the strength and deformation of the soil.

关 键 词：基坑开挖 施工工况 超负孔压 固结 

分 类 号：TU443[建筑科学—岩土工程]