循环荷载作用下超长桩动力特性研究  

Study on the dynamic characteristics of super-long pile under cyclic loading

作　　者：汪优[1] 秦志浩[1] 汤明明[1] WANG You;QIN Zhihao;TANG Mingming(School of Civil Engineering, Central South University, Changsha 410075, China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075

出　　处：《铁道科学与工程学报》2017年第8期1632-1638,共7页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51308552);湖南省高校创新平台开放基金资助项目(14K105)

摘　　要：考虑桩基土体在动力作用下强度弱化的基础上,通过拟合数值模拟结果和试验结果,验证强度折减法在FLAC3D中实现的可能性。建立超长桩的动力数值模拟模型,从循环荷载的频率、荷载幅值、恒载部分、循环次数、桩土刚度比和桩长方面对超长桩的动力特性进行分析。研究结果表明:循环荷载频率越大,超长桩桩顶累积沉降越小;荷载幅值越大,对应的超长桩桩顶累积沉降越大;循环荷载的恒载部分对超长桩的动力沉降影响不大;桩顶沉降随循环荷载次数增加而逐渐增大,并随循环次数的增加逐渐趋于稳定;桩土刚度比越大,对应的超长桩桩顶累积沉降越大;桩长越长,对应的超长桩桩顶累积沉降越小。On the basis of considering the strength weakening of pile foundation under dynamic action,thefeasibility of applying the strength reduction method in FLAC3D was validated by fitting the numericalsimulation results and experimental results.The numerical simulation model of super-long pile under cyclicloading was established.The dynamic characteristics of super-long pile were analyzed from the aspects offrequency,load amplitude,load amplitude,cycle times,ratio of pile to soil stiffness and pile length.The numericalanalysis shows that higher frequency and lower amplitude of load result in smaller accumulated settlement ofsuper-long pile top.The constant load of the cyclic load has little influence on the dynamic settlement of thesuper-long pile.The settlement of pile top gradually increases with the cyclic loading times,and tends to be stablewith the increase of the number of cycles.Higher ratio of pile to soil stiffness and shorter pile length result inbigger accumulated settlement of super-long pile top.

关 键 词：循环荷载 超长桩 土体强度弱化 强度折减法 

分 类 号：TU473.1[建筑科学—结构工程]