高速列车荷载作用下X形桩桩网复合地基累积沉降研究  

Accumulated settlement of X-shaped piled embankments under high-speed train loads

作　　者：牛婷婷[1,2,3] 吴富敏 张智超 陈志雄 丁选明 NIU Tingting;WU Fumin;ZHANG Zhichao;CHEN Zhixiong;DING Xuanming(School of Civil Engineering and Architecture,Anhui University of Science and Technology,Huainan,Anhui 232001,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing University,Chongqing 400045,China;College of Civil and Transportation Engineering,Hohai University,Nanjing,Jiangsu 210098,China;Key Laboratory of Geohazard Prevention of Hilly Mountains,Ministry of Natural Resources of China,Fuzhou,Fujian 350002,China)

机构地区：[1]安徽理工大学土木建筑学院,安徽淮南232001 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400045 [3]河海大学土木与交通学院,江苏南京210098 [4]自然资源部丘陵山地地质灾害防治重点实验室,福建福州350002

出　　处：《岩石力学与工程学报》2024年第1期236-247,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：安徽高校自然科学研究项目(2022AH050844);山地城镇建设与新技术教育部重点实验室开放基金资助(LNTCCMA–20220109);安徽省自然科学基金资助项目(2008085ME143)。

摘　　要：为了研究高速列车荷载作用下桩网复合地基累积沉降的发展规律,建立大比例尺X形桩桩网复合地基模型,开展一系列模型试验,探索X形桩桩网复合地基累积沉降的发展规律。结果表明:在循环振动20000次之后,相邻四桩中心处累积沉降最大,轨道板上沉降次之,桩顶沉降最小;相邻四桩之间“网兜效应”显著。随着循环加载次数的增加,各测点处累积沉降均在不断增大;当加载频率≤15 Hz时,在循环振动10000次后,各测点处累积沉降曲线逐渐变得平缓,沉降速率逐渐变小;当加载频率≥25 Hz时,随循环加载次数的增加,轨道板上累积沉降曲线几乎没有变缓的趋势,且累积沉降增长的速率较快。随着加载频率的增大,各测点处累积沉降逐渐变大,25 Hz时累积沉降出现极大值,有“类共振”现象发生。实际工程中,可通过增大路堤刚度,避免这类情况发生。随着加载幅值的增大,累积沉降线性单调增长;加载幅值每增加1 kN,轨道板上累积沉降平均增长1.27倍。最后通过分析对比提出了考虑列车速度、列车轴重等因素的累积沉降预测公式。To explore the accumulated settlement of piled embankments under high-speed train loads,a large-scale X-shaped piled embankment model was established.A series of model tests were conducted,and the evolution of the cumulative settlement of X-shaped piled embankments was investigated.The results show that after 20000 cycles of vibration,the accumulated settlement at the center of the adjacent four piles is the largest,followed by the track slab and then the pile top.Moreover,the“hang-up”effect in the square grid is significant.As the number of cyclic loading increases,the accumulated settlement at each measuring point continues to increase.When the loading frequency is≤15 Hz,after 10000 cycles of vibration,the accumulated settlement curves at each measuring point gradually become gentle,and the rate of settlement gradually decreases.Furthermore,when the loading frequency is≥25 Hz,the accumulated settlement curves on the track slab show little tendency to slow down with increasing cyclic loading times,and the rate of accumulated settlement growth is relatively fast.With an increasing loading frequency,the accumulated settlement at each measuring point gradually increases.The accumulated settlement reaches a maximum value at 25 Hz,and a“quasi-resonance”phenomenon occurs.In practical engineering,such situations can be avoided by increasing the stiffness of the embankment.As the loading amplitude increases,the accumulated settlement linearly monotonically increases.When the loading amplitude increases by 1 kN,the accumulated settlement on the track slab increases by an average 1.27 times.Finally,a prediction formula for accumulated settlement evolution considering factors such as the train speed and axle load was proposed through analysis and comparison.

关 键 词：基础工程 累积沉降 桩网复合地基 高速列车荷载 沉降预测 

分 类 号：TU47[建筑科学—结构工程]