落石冲击下预应力加筋土路堤变形及荷载传递机制  

Deformation and load transmission mechanism of prestressed reinforced embankment subjected to rockfall impacts

作　　者：马书文 卢谅[1,3,4] 王宗建 王经天[1,3] 李蓝星 MA Shu-wen;LU Liang;WANG Zong-jian;WANG Jing-tian;LI Lan-xing(School of Civil Engineering,Chongqing University,Chongqing 400045,China;Department of Architectural&Engineering,Chongqing Industry Polytechnic College,Chongqing 401120,China;Key Laboratory of New Technology for Construction of Cities in Mountain Area,Ministry of Education,Chongqing 400045,China;National Joint Engineering Research Center of Geohazards Prevention in the Reservoir Areas,Chongqing University,Chongqing 400045,China;College of River&Ocean Engineering,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆工业职业技术学院建筑工程学院,重庆401120 [3]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 [4]重庆大学库区环境地质灾害防治国家地方联合工程研究中心,重庆400045 [5]重庆交通大学河海学院,重庆400074

出　　处：《岩土力学》2023年第3期799-809,共11页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.52178314);重庆市研究生科研创新项目(No.CYB22031)。

摘　　要：针对偏远山区素填土公路在落石冲击下易产生大面积凹陷破坏的问题,提出运用预应力加筋土路堤解决的方法。为了探究预应力加筋土路堤在落石冲击下的变形性能、力学响应规律和荷载传递机制,设计并实施了落石冲击作用下预应力加筋土路堤和素填土路堤对比模型试验。试验发现:预应力加筋土路堤中形成的凹坑尺寸明显小于素填土路堤,体现了预应力加筋土路堤良好的抗冲击变形性能;随着冲击次数的增加,路堤刚度逐渐增加,导致路堤内部冲击附加应力时程曲线逐渐由“抛物线型单峰”转变为“双峰”分布,且预应力加筋土路堤工况中“双峰”的出现早于素填土路堤;落石在预应力加筋土路堤中的冲击力持续作用时间小于其在素填土路堤中的持续作用时间,且分布更趋均匀,更有利于冲击荷载的扩散;随着冲击次数的增加,预应力加筋土路堤内部冲击力传递率呈先增加后减小的变化趋势,与筋材变形规律一致。结合Levenberg-Marquardt优化算法得到了关于凹坑尺寸和冲击次数的预测方法,可为预应力加筋土路堤在崩塌灾害多发地区的工程应用提供借鉴,为工程预警提供参考。The prestressed reinforced soil structure was proposed to solve the problem of large-area depressions of soil highways under rockfall impacts in remote mountain areas.Comparative model tests for prestressed reinforced soil embankment and traditional soil embankment were conducted to explore the deformation performance,mechanical response,and load transmission mechanism of both embankments under rockfall impacts.The results show that the size of pits formed in prestressed reinforced soil embankment is significantly smaller than that in traditional soil embankment,which reflects the good impact deformation resistance of prestressed reinforced soil embankment.The embankment stiffness increases with the increase of impact times,resulting in the change of the time history of impact-induced additional stress in the embankment from“parabolic single peak”to“double peak”,and the“double peak”in the prestressed reinforced soil embankment occurs earlier than that in the traditional soil embankment.The duration of rockfall impact on the prestressed reinforced soil embankment is less than that on the traditional soil embankment,and the distribution of the impact on the prestressed reinforced soil embankment is more uniform,indicating that the prestressed reinforced soil embankment is more conducive to the impact diffusion.In addition,the internal impact load transmission ratio for prestressed reinforced soil embankment increases first and then decreases with the increase of impact times,which is consistent with the deformation law of reinforcement structure.The pit sizes corresponding to various impact times are predicted by the Levenberg-Marquardt optimization algorithm,which can provide reference for the engineering application of prestressed reinforced soil embankment and early warning in collapse disaster prone areas.

关 键 词：落石冲击 预应力加筋土路堤 冲击变形 附加应力 冲击持续时间 冲击力传递率 

分 类 号：TU472[建筑科学—结构工程]