矩形位移模式下被动桩砂土绕流的模型试验研究  

MODEL TEST ON SAND FLOWING AROUND PASSIVE PILE UNDER RECTANGULAR DISPLACEMENT MODE

作　　者：关振长[1] 陈文菁 苏继明 赖荫楠 邓涛[1] GUAN Zhenchang;CHEN Wenjing;SU Jiming;LAI Yinnan;DENG Tao(College of Civil Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]福州大学,土木工程学院,中国福州350108

出　　处：《工程地质学报》2023年第1期327-334,共8页Journal of Engineering Geology

基　　金：国家自然科学基金资助(资助号:51678155)。

摘　　要：被动桩桩周土体易发生绕桩流动,但绕桩流动土体的位移特征及其影响因素迄今还缺乏深入研究。采用自主研制的模型试验装置,对矩形位移模式下砂土绕圆形被动桩流动过程进行详细测试与分析,研究了桩径、加载速度及土体密度对砂土的特征位移和桩身受力的影响。试验结果表明,砂土绕桩流动过程可分为迎土侧土体隆起、桩周土体绕流和背土侧土体沉陷3个阶段。桩径或土体密度越大,桩周砂土越不易发生绕桩流动;桩周土体移动速度越大,则越易发生绕桩流动。分析结果进一步表明,土体滑动面的位置可根据桩身绕流阻力曲线的拐点来判断,在土体滑动面以上,模型桩绕流阻力沿桩长沿深度大致呈线性增长,其值始终小于沈珠江绕流阻力理论值。Although the phenomenon of sand flowing around passive pile was observed, there is still a lack of systematical studies on the features of sand flowing as well as its related factors. Using the model experimental system designed and manufactured by Fuzhou University, the phenomenon of sand flowing around a circular passive pile was well tested and analyzed. The influence of pile diameter, loading velocity and sand density on the sand characteristic displacement and the pile drag force were studied. According to the test results, the sand flowing process around the passive pile could be divided into three stages: sand uplift on the head side, sand flowing around the pile and sand collapse on the back side. The increasing of pile diameter and sand density could hamper the sand flowing phenomenon around the pile, while the increasing of sand velocity could facilitate the sand flowing phenomenon. Furthermore, the position of sliding surface can be determined from the curve inflexion of drag force, the drag force above the sliding surface increased linearly with depth, and was always less than its counterpart calculated from the Shen-Zhujiang’s formula.

关 键 词：被动桩 砂土绕流 模型试验 绕流阻力 

分 类 号：TU473.1[建筑科学—结构工程]