摘要
桩-土界面循环弱化机制对于桩体的承载性能具有控制作用,基于自主研发的大尺度恒刚度界面剪切仪,进行不同剪切位移幅值和初始法向应力下恒刚度桩-土界面循环弱化机制研究,并推导出可用于预测不同试验条件下剪切应力的弱化公式。结果表明:界面剪切应力-剪切位移关系曲线呈“闭回环”状发展;随着循环次数的增加剪切应力不断弱化,弱化主要发生在剪切的初始阶段,其主要原因为桩-土界面土颗粒的重新排列和剪碎细化,界面出现减压软化现象;初始法向应力越大,剪切位移幅值越大,随着循环次数的增加剪应力弱化速率越快。采用非线性对数型曲线进行拟合与真实数据曲线相似度达90%左右,对研究桩-土界面弱化机制具有一定的意义。
The cyclic weakening mechanism of pile-soil interfaces can affect the bearing capacity of piles.This pa⁃per investigated the cyclic weakening mechanism of constant normal stiffness in pile-soil interface under different shear-displacement amplitudes and initial normal stress parameters.An independently developed large-scale con⁃stant normal stiffness shear device is used in this study.The results show that the shear stress-displacement curve of the interface develops in a"closed loop"shape.The shear stress continues to weaken when the number of cycles increase.The weakening mainly occurs in the initial stage of shearing.This is mainly due to the rear⁃rangement and breakage of soil particles at the pile-soil interface,as well as decompression and softening at the interface.These findings also indicate that the greater the initial normal stress leads to larger shear-displacement amplitude.Furthermore,the increase in number of cycles results in a rapid weakening of the shear stress.The logarithmic weakening can be used to predict shear stress under different test conditions.The results show that nonlinear logarithmic curve fitting has about 90%similarity with the real data curve,which is significant in studying the weakening mechanism of pile-soil interfaces.
作者
刘俊伟
朱娜
凌贤长
万志朋
黄孝义
赵国晓
LIU Junwei;ZHU Na;LING Xianzhang;WAN Zhipeng;HUANG Xiaoyi;ZHAO Guoxiao(School of Civil Engineering,Qingdao University of Technology Qingdao,266033,China;College of Environmental Science and Engineering,Ocean University of China Qingdao,266100,China;School of Civil Engineering,Harbin Institute of Technology Harbin,150090,China;The Second Construction Limited Company of China Construction Eighth Engineering Division Jinan,250014,China;China Railway Construction Engineering Group Shandong Co.,Ltd.Qingdao,266100,China;Chongqing Research Institute of Harbin Institute of Technology Chongqing,401151,China)
出处
《振动．测试与诊断》
EI
CSCD
北大核心
2022年第6期1163-1169,1246,1247,共9页
Journal of Vibration,Measurement & Diagnosis
基金
国家自然科学基金资助项目(42277135,41772318)
山东省优秀青年基金资助项目(ZR2021YQ31)。
关键词
桩-土界面
法向恒刚度
弱化效应
颗粒破碎
对数型弱化公式
pile-soil interface
constant normal stiffness
weakening effect
particle breakage
logarithmic weak⁃ening formula
