膨胀土边坡加筋作用的对比模型试验  

Comparison Model Test on Effect of Geogrid Reinforcement for Expansive Soil Slope

作　　者：肖杰[1] 杨和平[1] 符浩[1] 唐咸远[1] 

机构地区：[1]长沙理工大学交通运输工程学院,湖南长沙410004

出　　处：《中国公路学报》2014年第7期24-31,共8页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(50978035;51108049);交通运输部西部交通建设科技项目(2009 353 311 060);道路灾变防治及交通安全教育部工程研究中心开放基金项目(kfi090303);广西交通科技项目(2011-20)

摘　　要：为获得大气干湿循环条件下土工格栅加筋柔性支护治理膨胀土边坡坍滑的工作机理,用南宁外环膨胀土制作了一侧加筋一侧素土的室外大型边坡模型,分别埋设体积含水率探头、水平与竖向土压力盒、柔性位移计等测试元件,实施人工降雨模拟干湿循环并跟踪监测两侧坡体的含水率、土压力变化及不同部位格栅的应变变化。结果表明:加筋侧土体的相对平衡含水率及其波动范围均比未加筋侧小;加筋侧的水平与竖向土压力比明显小于未加筋侧;各层格栅越靠近坡面,其应变变化越快,峰值出现越早,沿水平深度呈"凸"形分布,但远小于其允许应变值;验证了膨胀土堑坡柔性支护的"框箍"作用机理。In order to understand the mechanism of geogrid reinforcement flexible support for treatment of expansive soil slope sliding under the condition of dry-wet cycles, outdoor large-scale slope models reinforced and unreinforced by geogrid were made with expansive soil from Nanning Outer Ring expressway. Volumetric moisture probes, horizontal and vertical earth pressures cells and flexible displacement meters were buried in the models. Artificial rainfall was used to simulate the dry-wet cycles. The changes in water contents, vertical and horizontal earth pressures of both slopes and the strains of different locations of geogrid were monitored. The results show that the relative equilibrium water content and its fluctuation range of reinforced slope are all less than those of unreinforced slope. The horizontal and vertical earth pressure ratio of reinforced slope is significant less than that of unreinforced slope. The geogrid strain changes faster and its peak occurs earlier with geogrid closer to slope surface. The variation in geogrid strain is in convex along the horizontal direction, but all the strains are far less than maximum allowable strain. Therefore, the frame hoop mechanism of geogrid reinforcement flexible support for treatment of expansive soil slope is verified.

关 键 词：道路工程 膨胀土边坡 模型试验 土工格栅加筋 干湿循环 

分 类 号：U416.14[交通运输工程—道路与铁道工程]