循环荷载下楔形劲芯水泥土复合桩工作特性试验研究  

Dynamic response and characteristics of tapered rigid core composite cement-soil piles under cyclic loading

作　　者：何杰[1] 郭端伟 宋德新 刘孟鑫 张磊 文奇峰 HE Jie;GUO Duan-wei;SONG De-xin;LIU Meng-xin;ZHANG Lei;WEN Qi-feng(College of Civil Engineering,Hunan University of Technology,Zhuzhou,Hunan 412007,China;Hunan No.2 Engineering Co.,Ltd.,Changsha,Hunan 410015,China)

机构地区：[1]湖南工业大学土木工程学院,湖南株洲412007 [2]湖南省第二工程有限公司,湖南长沙410015

出　　处：《岩土力学》2023年第5期1353-1362,1374,共11页Rock and Soil Mechanics

基　　金：湖南省自然科学基金资助项目(No.2020JJ6007)。

摘　　要：楔形劲芯水泥土复合桩作为一种新型组合桩,为探究其在公路、铁路等长期承受循环荷载下工程应用的工作性状,对4根不同桩芯楔角、静荷载比和循环荷载比的复合桩进行模型试验,研究了静载极限承载力及循环荷载下累计沉降、桩身轴力分布、桩端阻力和侧摩阻力。试验结果表明:静载作用下楔形内芯复合桩的承载能力要优于等截面内芯复合桩;复合桩累计沉降会随着静荷载比和循环荷载比的增大而增大,并在不同动静荷载组合下可分为稳定型、发展型和破坏型3种类型,同时给出满足各类型的荷载取值范围;芯桩与水泥土外桩之间的相互作用并未发生明显弱化现象,楔形芯桩复合桩能充分发挥桩侧上部土体的侧摩阻力,并能有效减弱芯桩端部应力集中现象,因此其抵抗循环荷载的能力要优于等截面芯桩的复合桩。Tapered rigid core composite cement-soil pile is an emerging type of composite pile.In order to investigate its bearing behavior in engineering applications such as highways and railways under long-term cyclic loading,model tests were conducted on four composite piles with different pile core wedge angles,static loading ratios and cyclic loading ratios.The ultimate bearing capacity under static loading as well as the cumulative settlement,pile axial force distribution,tip resistance and side friction resistance were evaluated.The results indicated that the bearing capacity of tapered inner core composite piles under static loading was better than that of constant cross-section inner core composite piles.The cumulative settlement of composite piles increased with the increase of static loading ratio and cyclic loading ratio,and can be classified into three types of stability,development and failure under different combinations of dynamic and static loading.At the same time,the value range of load satisfying each type was also given.The interaction between the core pile and the cement-soil outer pile was not noticeably diminished,and the composite pile with a tapered core pile could fully mobilize the side friction resistance of the upper soil around the pile sides and effectively reduce the stress concentration at the tip of the core pile.Therefore,its ability to resist cyclic loading was better than that of the composite pile with a constant cross-section core pile.

关 键 词：楔形劲芯水泥土复合桩 循环荷载 极限承载力 累计沉降 桩身应力 

分 类 号：TU473[建筑科学—结构工程]