不同应力水平下钢-粉质黏土恒刚度界面循环剪切特性研究  

Study on the Cyclic Shear Characteristics of the Constant Stiffness Interface Between Steel and Silty Clay Under Different Stress Levels

作　　者：何冬 于爽 He Dong;Yu Shuang(PowerChina Roadbrige Group Co.,Ltd.,Beijing 100048,China)

机构地区：[1]中电建路桥集团有限公司,北京100048

出　　处：《科技通报》2025年第4期64-72,共9页Bulletin of Science and Technology

摘　　要：研究钢管桩打桩过程中的桩-土界面循环剪切特性,对桩基稳定性和承载力至关重要。本文利用多功能土体-结构物界面循环剪切试验仪,研究了在不同应力水平(50 kPa和200 kPa)下的黄河粉质黏土-桩界面恒刚度循环剪切特性,分析了法向应力、剪切应力、等效界面摩擦角和界面剪切刚度的动力响应。结果表明,法向应力随着循环次数增加逐渐减小并稳定,且循环剪切位移幅值和含水率增大时,法向应力衰减加剧,200 k Pa下法向应力衰减速率较50 k Pa更快;随着循环剪切位移幅值增加,剪切应力滞回圈变宽,峰值剪切应力增加;剪切应力与法向应力关系曲线在50 k Pa下呈现“蝴蝶状”变化,在200 kPa下呈现“波浪状”变化;等效界面摩擦角随循环次数增大逐渐增加并趋于平稳,在50 kPa下变化更为明显;界面剪切刚度随着应力水平、循环次数、位移幅值和含水率增加而下降。研究成果可为黄河粉质黏土地区桩基优化设计提供理论借鉴与数据支撑。Studying the cyclic shear characteristics of the pile-soil interface during the driving process of steel pipe piles is crucial for the stability and bearing capacity of pile foundations.A study was conducted on the cyclic shear behavior of the pile-Yellow River silty clay interface under varying stress levels(50 kPa and 200 k Pa) using a multifunctional soil-structure interface cyclic shear tester.The dynamic responses of normal stress,shear stress,equivalent interface friction angle,and interface shear stiffness were analyzed.Results indicated that the normal stress decreased gradually and stabilized with increasing cycle times.The attenuation of normal stress intensified with greater cyclic shear displacement amplitude and water content.The rate of normal stress attenuation was more rapid at 200 kPa compared to 50 kPa.As the amplitude of cyclic shear displacement increased,the hysteresis loop of shear stress widened,and the peak shear stress increased.The relationship curve between shear stress and normal stress displayed a butterfly-like variation at 50 kPa and a wavy variation at 200 kPa.The equivalent interface friction angle increased progressively and tended to stabilize with more cycle times,with more pronounced changes observed at 50 kPa.Interface shear stiffness decreased with increasing stress level,cycle number,displacement amplitude,and water content.These research findings offer a theoretical reference and data support for optimizing pile foundation designs in the Yellow River silty clay region.

关 键 词：钢管桩 黄河粉质黏土 桩-土界面循环剪切 恒刚度 应力水平 

分 类 号：TU473.1[建筑科学—结构工程]