反压土对悬臂式支护结构嵌固深度的影响研究  

Influence of earth berm on embedment depth of cantilever retaining structure for pit excavation

作　　者：李顺群[1,2] 郑刚[3] 王英红[4] 

机构地区：[1]天津城市建设学院土木工程系,天津300384 [2]天津市软土特性与工程环境重点实验室,天津300384 [3]天津大学建筑工程学院,天津300072 [4]天津城市建设学院电子与信息工程系,天津300384

出　　处：《岩土力学》2011年第11期3427-3431,3436,共6页Rock and Soil Mechanics

基　　金：教育部科学技术研究重点项目(No.210004);天津市自然科学基金(No.11JCYBJC02900);冻土工程国家重点实验室开放基金(No.SKLFSE200906)

摘　　要：基于Rankine土压力理论、滑移线场理论和Boussinesq解答在均布条形荷载作用下的表达式,建立了考虑反压土自重对坑底土体水平抗力的增强作用和反压土本身的嵌固作用两种机制时悬臂式支护结构嵌固深度的计算方法,并进行了算例分析。研究表明:虽然反压土能提供给支护结构的水平抗力较小,但由于其合力力臂较大,因此对支护结构有明显的嵌固作用;另外,反压土的自重能明显提高坑底土体的水平抗力。综合考虑反压土的以上效应后,支护结构的嵌固深度可以明显减小。基坑内侧预留反压土的施工方法可以省去水平支撑、降低支护结构深度,还可以节约投资和缩短工期,具有良好的经济效益、社会效益和环境效益。因此,在条件许可的情况下,该施工方法应优先选用。The earth pressure theory by Rankine and the formula for calculating subsidiary stress by Boussinesq were employed to study the interaction between earth berm and retaining structure for cantilever retaining structure.On one hand,the earth berm in a pit can strengthen horizontal resisting force of the soil body in the passive zone owing to its gravity.On the other hand,it can reinforce the stability of the retaining structure due to the horizontal resisting force of itself.Considering the two points aforementioned,a method is constructed to determine embedment depth of retaining structures.And more,a pit excavation is computed by the proposed method for further investigations.The study shows that reinforcement of the earth berm on retaining structure is remarkable because of the large moment arm even the magnitude of the horizontal resisting force is not very great.Therefore,the needed embedment length of the retaining structure in the pit excavation having earth berm can be distinctly cut.It can be concluded that the earth berm method should be recommended in suitable situations for its better economy,higher efficiency and lower pollution.

关 键 词：基坑开挖 反压土 悬臂 嵌固深度 水平抗力 

分 类 号：TU470[建筑科学—结构工程]