桩-土界面特性对砂土地基中抗拔桩承载特性影响的模型试验研究  

Model experimental research on effects of properties of interface between piles and sand on bearing behavior of uplift piles in sand

作　　者：罗耀武[1,2] 胡琦[3] 凌道盛[1] 陈峥[4] 陈云敏[1] 

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,杭州310027 [2]黄河勘测规划设计有限公司,郑州450003 [3]浙江工业大学,杭州310014 [4]华东电力设计院,上海200063

出　　处：《岩土力学》2011年第3期722-726,732,共6页Rock and Soil Mechanics

基　　金：中国博士后科学基金(No.20080441232)

摘　　要：针对砂土地基中不同L/d的抗拔桩进行了模型试验,模型桩采用了3种不同界面,结合界面剪切试验探讨了桩-土界面特性对抗拔桩荷载-位移曲线、极限承载力及残余承载力的影响,得到了以下几点结论:模型桩长径比L/d不同时,每种界面抗拔桩荷载-位移曲线是类似的,光滑钢桩上拔力达极限承载力后保持不变,粗糙界面模型桩上拔力达极限承载力后降低,直至达残余承载力;抗拔桩达极限承载力时的静止土压力系数K受桩-土界面粗糙程度的影响,界面越粗糙,K值越大;界面越粗糙,抗拔桩残余承载力与极限承载力的比值越小,该比值随L/d的变化较小;对于粗糙界面抗拔桩,残余承载力与极限承载力的差别一部分是由于桩-土界面摩擦角的降低引起的,另一部分是抗拔桩达到极限承载力后作用在桩表面上的水平土压力降低引起的。In order to study the load-displacement curves,the ultimate uplift capacity and the residual uplift capacity of piles in sand,a testing program for different L/d model piles pullout tests is conducted.The model piles have three different roughness interfaces,and the shearing behavior of interfaces are tested.The load-displacement curves are similar for the piles with same interface when L/d is different.The uplift load of smooth pile reaches a steady value after the ultimate uplift capacity.The uplift load of rough pile becomes smaller after the ultimate uplift capacity;then it reaches the residual uplift capacity.When the piles are at failure,the lateral earth pressure coefficient K are affected by the roughness of pile;the rougher the pile is,the bigger the K is.The residual uplift capacity,expressed as a percentage of the ultimate uplift capacity is smaller for rougher piles;and the ratio is about the same for different L/d piles.The residual uplift capacity are smaller than the ultimate uplift capacity for rough piles;this is attribute to two reasons,one is the reduction of interface friction angle,the other is the reduction of lateral earth pressure.

关 键 词：界面 抗拔桩 承载特性 模型试验 

分 类 号：TU473[建筑科学—结构工程]