循环荷载下筋材对桩承式低路堤荷载传递机制的影响试验  

Effect of Geosynthetic Reinforcements on Load Transfer Mechanism of Pile-supported Low Embankments Under Cyclic Loading

作　　者：徐传堡 贾亚飞 郑俊杰 郑烨炜 XU Chuan-bao;JIA Ya-fei;ZHENG Jun-jie;ZHENG Ye-wei(School of Civil Engineering,Wuhan University,Wuhan 430072,Hubei,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072

出　　处：《中国公路学报》2024年第6期66-75,共10页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52078236,52078392)。

摘　　要：软土地区路基在长期交通荷载作用下,容易出现路面开裂、不均匀沉降等问题。桩承式路堤是软土地区最常用的路基加固方法之一,研究其在循环荷载下的动力特性,对于指导交通荷载下路堤的长期沉降控制具有重要意义。然而,现有的研究主要集中于静载下的高路堤,对循环荷载下低路堤工作性能的研究较少。为此,开展了2组模型试验探究循环荷载下筋材对桩承式低路堤荷载传递机制的影响,分析了路堤沉降、荷载传递效率、应力应变分布等的变化特征。研究结果表明:桩承式低路堤在动载作用下产生较大的累积变形,筋材的加入有利于减小累积变形的发展。在所提试验条件下,加筋低路堤的累积变形减小了24.5%;在动载作用下,桩承式低路堤荷载传递效率随着循环次数的增加而逐渐降低,随后保持稳定;加筋增大了荷载传递效率,减小了荷载传递效率的降低幅度。在较大的循环次数和动载幅值下,未加筋低路堤的荷载传递效率持续下降,而加筋路堤缓慢增大;未加筋低路堤在静载作用下较早地形成部分土拱,随着动载的施加,土拱逐渐弱化;加筋低路堤的应力重分布现象有所改善。基于试验结果,提出了动载作用下桩承式低路堤的界定方法,并基于荷载传递效率降低系数,对模型试验中低路堤的工作性能进行了评价。In soft soil regions,roadbeds are prone to problems such as pavement cracking and uneven settlement under a long-term cyclic traffic loading.Pile-supported embankments are one of the most commonly used structures for ground modification in soft soil areas.It is crucial to investigate their dynamic responses for a better control of long-term embankment settlements under traffic loading.The existing research is primarily focused on high embankments under static loading,with limited studies on the working performances of low embankments under cyclic loading.Two model tests were conducted in this study to investigate the influences of geosynthetic reinforcements on the load transfer mechanism of pile-supported low embankments under cyclic loading.The embankment settlement,pile efficacy,and stress-strain distribution were analyzed.The results indicate that pile-supported low embankments exhibit significant cumulative deformations under cyclic loading,where the reinforcement facilitates the reduction in the development of cumulative settlements.The cumulative settlement of reinforced low embankments decreases by 24.5%under the conditions of this study.The pile efficacy of pile-supported low embankments under cyclic loading gradually decreases with the increase in the number of load cycles before stabilization.The reinforcement increases the pile efficacy and reduces the magnitude of efficacy degradation.The pile efficacy of unreinforced low embankments continuously decreases under higher loading amplitudes and cycles,while that of reinforced embankments increases slowly.Unreinforced low embankments form a partial arching earlier under static loading,and gradually degrade with the application of cyclic loading,while the reinforced embankments exhibit an improvement in stress redistribution phenomena.Based on the experimental results,a method to define pile-supported low embankments under cyclic loading is proposed,and an evaluation of the working performances of low embankments is conducted based on the pile efficacy re

关 键 词：路基工程 土拱演化 荷载传递机制 桩承式路堤 循环荷载 土工合成材料 

分 类 号：U416.1[交通运输工程—道路与铁道工程]