软土地区地下室增层开挖对既有桩基沉降性状的影响  

Settlement analysis of building piles associated with excavation beneath existing basement in soft soil

作　　者：单华峰[1,2] 夏唐代[1,2] 俞峰[3] 郑晴晴[1,2] 

机构地区：[1]浙江大学滨海和城市岩土工程研究中心,浙江杭州310058 [2]浙江大学软弱土与环境土工教育部重点实验室,浙江杭州310058 [3]浙江理工大学建筑工程学院,浙江杭州310018

出　　处：《中南大学学报（自然科学版）》2016年第6期1995-2000,共6页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(41472284;51378463)~~

摘　　要：首先,通过荷载传递法建立轴向荷载作用下单桩的受力模型并得到其控制方程,然后引入桩侧软化及桩端双曲线荷载传递函数,同时给出极限侧摩阻力及极限端阻力的表达式。在此基础上,结合工程实例,通过自编的迭代程序得出单桩的p-s曲线,并与已有的计算方法进行比较,验证提出计算方法的可行性。研究开挖深度对若干关键问题的影响,如桩侧极限摩阻力、桩端极限阻力及基桩承载性状。最后结合案例分析增层开挖施工前后,单桩在极限承载力及工作荷载作用下产生的沉降量。研究结果表明:不同的开挖深度对桩端极限阻力影响较小,而对桩侧极限摩阻力影响较大;随着开挖深度增加,桩顶沉降量也不断增大。该工程的增层开挖在变形控制方面安全可靠。Firstly, an axially-loaded pile model and a governing equation of single pile were established by the load transfer method. The skin friction softening model and pile tip load transfer model were then introduced, and the expression of ultimate skin friction and ultimate end resistance were derived. On this base, a case history was analyzed by employing an iterative process, thus the p-s curve of single pile was obtained. The feasibility of the proposed method could be assessed by a comparison with existing methods. The effects of excavation depth on some key issues, such as the ultimate skin friction, end resistance and the overall bearing behavior of piles were analyzed. Finally, the pile head settlements before and after excavation corresponding to the ultimate and working capacities were calculated. The results show that the excavation depth is more sensible to the skin friction, than to the end resistance, and the pile head settlement increases with the increase of excavation depth. The further excavation is reliable for the involved case with respect of the deformation control.

关 键 词：软土 开挖 既有建筑 桩基沉降 极限阻力 

分 类 号：TU473.2[建筑科学—结构工程]