循环荷载作用下钢桩-软黏土接触面剪切特性研究  

Shear characteristics of steel pile-soft clay interface under cyclic loading

作　　者：周洁[1,2] 朱柯凡 刘成君 沈盼盼 ZHOU Jie;ZHU Kefan;LIU Chengjun;SHEN Panpan(Department of Geotechnical Engineering,College of Civil Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering(Tongji University),Ministry of Education,Shanghai 200092,China;Shanghai Investigation,Design&Research Institute Co.,Ltd.,Shanghai 200335,China)

机构地区：[1]同济大学地下建筑与工程系,上海200092 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]上海勘测设计研究院有限公司,上海200335

出　　处：《岩土工程学报》2024年第S02期49-53,共5页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金面上项目(42477182);上海勘测设计研究院有限公司科研项目(2023FD(83)-001)。

摘　　要：目前,中国海上风电工程的建设已进入快速发展阶段。海上风电机常采用大直径钢管桩作为基础,然而现在的桩基承载力设计预测方法往往基于小直径柔性桩,不适用于大直径刚性桩。因此需要研究海上桩基桩-土界面的相互作用,来对海上大直径刚性桩基的设计预测方法进行优化。使用循环荷载作用下钢桩-软黏土大型接触面剪切试验数据,建立法向循环荷载作用下钢与黏性土接触面剪切试验的离散元模型,对各个细观参数进行标定,分别研究动荷载频率和幅值对剪切特性的影响,并进行了细观机理分析。数值模拟结果表明动荷载频率和幅值越大,钢与黏性土接触面强度越小,其中动荷载幅值的影响较为明显。通过细观机理分析可以发现:动荷载频率和幅值越大,接触面处黏性土的颗粒位移越小;静荷载下黏性土的颗粒间作用力大于动荷载下的颗粒间作用力;动荷载会导致颗粒间的扰动,从而使接触面强度减小。研究结果可以为海上风电桩基承载力的准确预测提供理论基础。Recently,construction of offshore wind power has developed rapidly in China.However,the current design methods for the bearing capacity of pile foundations are often based on small-diameter flexible piles,which are not applicable to the real situation.At the same time,there are thick layers of clay in the field.Therefore,it is necessary to study the shear characteristics of the steel pile-soft clay interface to optimize the design method.The large-scale interface shear test model corresponding to the laboratory tests is established by using the numerical simulation software,and the values of the micro-parameters are validated.The simulated results fit the laboratory test results well,and the model can accurately reflect the pile-clay interaction during shearing.Based on this model,the shear characteristics of the steel-clay interface under different cyclic loading frequencies and amplitudes are analyzed.The results show that while the interface strength slightly decreases with the increase of the frequency and amplitude of cyclic loading,particularly the effects of the amplitude are more obvious.The mechanical response of clay from the mesoscopic scale is also analyzed.The greater the cyclic loading frequency and amplitude,the smaller the horizontal displacement of the particles.The research results can provide support to predict the bearing capacity of pile foundation of offshore wind power.

关 键 词：钢桩-软黏土接触面 大型接触面剪切试验 循环荷载 数值模拟 

分 类 号：TU411[建筑科学—岩土工程]