循环荷载下冻土桩基力学特性研究  

Mechanical properties research about frozen soil pile foundation under cyclic loading

作　　者：王海新[1] 吴亚平[1] 孙安元 谢长群[2] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]商丘学院土木工程学院,河南商丘476000

出　　处：《铁道科学与工程学报》2017年第10期2111-2117,共7页Journal of Railway Science and Engineering

基　　金：中国铁路总公司科技研究开发计划项目(2015G005-C)

摘　　要：通过给冻土单桩模型上端施加循环荷载,分析循环荷载幅值、频率及冻土温度的变化对桩身应变、桩身轴力、桩侧冻结应力以及桩土相对位移的影响规律,开展循环荷载作用下冻土桩基力学特性的研究。研究结果表明:桩身应变随着加载时间先增加后稳定,且低温环境和小荷载条件下更有利于桩身应变的稳定;桩身的应变随荷载幅值及频率的增加而变大,随温度的降低而减小;桩身轴力沿着桩深不断减小,是由于桩侧土体使桩从上部开始受力;低温环境下桩身轴力相对较小,这是冻土地区桩基稳定的有利条件;桩侧冻结应力首先从桩基的上端发挥作用,并逐渐向下传递,分别增大荷载幅值、频率及降低温度都会增强桩侧冻结应力;桩土相对位移受荷载幅值、频率及温度的影响明显,频率能够影响桩土的承载模式。By applying cyclic loading on frozen soil model of single pile, this test analyzed the influence of thesize and frequency of the cycle loading and temperature on the strain of pile, pile side freezing stress, axial forceof pile and relative displacement of piles and soil. The mechanical properties of frozen soil pile foundation undercyclic loading were then studied. The results show that pile strain increases initially and becomes stableeventually with the loading time. The pile strain needs less time to stabilize under low temperature environment orsmall load. The strain of pile gets bigger along with the increase of load amplitude, while it decreases with thedecrease of temperature and becomes larger with the increase of frequency. Pile side freezing stress acts on thepile from the top of the pile foundation and gradually passing down, increasing of load amplitude and frequencyor decreasing of temperature will increase pile side freezing stress. Pile axial force gradually becomes smalleralong the pile depth, because the effect acts begin from the top. The axial force of pile decreases whentemperature is smaller. The relative displacement of piles and soil changes significantly under the influence ofload amplitude, and frequency and temperature, and frequency can affect the bearing model of pile soil.

关 键 词：冻土 桩基 模型试验 循环荷载 力学特性 

分 类 号：TU473[建筑科学—结构工程]