摘要
针对中国南方地区红黏土低路堤路基工作区深度与毛细吸力影响区重叠引起的大变形、不均匀沉降等问题,开展不同含水状态下红黏土低路堤动静力响应模型试验,研究不同荷载、加载频率、加载次数及含水量条件下红黏土低路堤附加应力、动孔隙压力比、竖向动位移及累积变形的变化规律。研究结果表明:动应力幅值、动孔隙压力比、累积竖向变形沿深度方向先迅速减小,后缓慢减小;动孔隙压力比、竖向动位移幅值与含水量呈正相关,动应力幅值与含水量呈负相关,饱和含水量时路堤顶面处的动应力、动孔隙压力比、竖向动位移分别为最优含水量时路堤顶面处的71.36%、190%、231%,需在路堤底部设置防渗土工布或一定厚度级配碎石层以控制毛细水上升;动荷载作用下低渗透性非饱和红黏土将会产生动孔隙气压力;动荷载作用下红黏土低路堤动孔隙压力存在累积效应;红黏土低路堤累积竖向变形云图呈以动荷载作用位置为中心向外递减的半椭圆状分布,距路堤顶面一定范围内属于累积竖向变形集中区,累积侧向变形云图沿动荷载作用中心线基本对称分布;不同加载方式对红黏土低路堤附加应力与累积竖向变形的影响程度为:长时动载>静载>短时动载。研究成果可为南方地区红黏土低路堤结构的设计与安全运营提供参考。
Aiming at the problems of large deformation and uneven settlement caused by the overlap of the depth and capillary suction influence area of the red clay low embankment working area in southern China,dynamic and static response model tests of the red clay low embankment under different water content were conducted.The variation laws of additional stress,dynamic pore pressure ratio,vertical dynamic displacement,and cumulative deformation under different loads,loading frequencies,loading cycles,and water content conditions were studied.The research results indicate that the amplitude of dynamic stress,dynamic pore pressure ratio,and cumulative vertical deformation decrease along the depth direction first rapidly and then slowly decrease.The amplitude of dynamic pore pressure ratio and vertical dynamic displacement are positively correlated with the water content,while the amplitude of dynamic stress is negatively correlated with water content.When saturated with water,the dynamic stress,dynamic pore pressure ratio,and vertical dynamic displacement at the top of the embankment are 71.36%,190%,and 231%of those at the optimal water content,respectively.It is necessary to set anti-seepage geotextile or a certain thickness graded gravel layer at the bottom of the embankment to control the rise of capillary water.Under dynamic loading,low permeability unsaturated red clay will generate dynamic pore air pressure and promote a cumulative effect of dynamic pore pressure on low embankment of red clay.The accumulated vertical deformation cloud map of red clay low embankment shows a semi elliptical distribution that decreases outward with the center of the dynamic load action position.Within a certain range from the top surface of the embankment,it belongs to the accumulated vertical deformation concentration area.The cumulative lateral deformation cloud map is symmetrically distributed along the centerline of the dynamic load action.The influence of different loading methods on the additional stress and accumulated vertical deformation of red clay low embankment is:long-term dynamic load>static load>short-term dynamic load.The research results can provide reference for the design and safe operation of red clay low embankment structures in southern regions.
作者
邱祥
李耀
李锦鸿
陈文胜
吴勇
Qiu Xiang;Li Yao;Li Jinhong;Chen Wensheng;Wu Yong(Changsha University of Science&Technology,Chang-sha 410114,China;Guangxi Communications De-sign Group Co.,Ltd.,Nanning 530029,China)
出处
《土木工程学报》
北大核心
2025年第9期141-152,共12页
China Civil Engineering Journal
基金
国家自然科学基金(52278439,51908073,52078066)
湖南省科技创新计划(2023RC3138)
湖南省自然科学基金面上项目(2023JJ30035)
湖南省教育厅自然科学青年项目(21B0317)。
关键词
道路工程
红黏土
低路堤
动力响应特性
加载方式
含水量
road engineering
red clay
low embankment
dynamic response characteristics
loading methods
moisture content
