高路堤返包式加筋土挡墙的试验研究  

Experimental Study on Reinforced Retaining Wall with Wrapped Face on High Embankment

作　　者：徐华[1] 夏磊 任鑫 陈紫云[2] 张小波 XU Hua;XIA Lei;REN Xin;CHEN Zi-yun;ZHANG Xiao-bo(School of Civil Engineering,Southwest Jiaotong University,Chengdu Sichuan 610031,China;Sichuan Communications Surveying&Design Institute,Chengdu Sichuan 610017,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]四川省交通运输厅交通勘察设计研究院,四川成都610017

出　　处：《公路交通科技》2021年第6期70-77,共8页Journal of Highway and Transportation Research and Development

基　　金：甘孜州交通建设科技项目(MML2016001)。

摘　　要：为研究高路堤返包式加筋土挡墙结构的荷载状态和筋土相互作用,以我国西南山区一典型的高路堤返包式加筋土挡墙为工程依托,其上部为8 m高的未加筋路肩,下部为14 m高的返包式土工格栅加筋路堤,现场安装土压力盒及筋带柔性位移计,开展为期1 a的现场监测试验,深入分析加筋土体内部垂直土压力、土工格栅应变的分布规律以及加筋土挡墙的潜在破裂面形式。测试结果表明:格栅的网兜效应在土体中形成托举力,使得土工格栅可以有效改善筋土复合体内部的应力分布,减小垂直土压力;对于上部有路肩填土作为超载的加筋路堤挡墙结构,其加筋土体可划分为"斜坡荷载影响区"和"垂直荷载影响区",两区分界位置附近的垂直土压力和土工格栅应变均出现峰值;土工格栅应变沿筋长方向呈非线性分布,距离坡面4 m内的土工格栅变形在工后有随时间增大的趋势,但筋带最大拉伸应变仅为1.32%,筋带受到的最大荷载不超过40 kN/m,远小于其极限拉伸强度(165 kN/m);由实测筋带变形推算的潜在破裂面与采用GeoStudio和Geo5数值计算的潜在破裂面趋势较为一致,但数值计算的潜在破裂面相对于实测推算更靠近加筋土体内部,路堤的整体稳定性更高,数值计算结果偏于安全。In order to research the load state of the reinforced retaining wall with wrapped face on high embankment and the interaction between the reinforcement and soil,based on a typical reinforced retaining wall with wrapped face on high embankment in the mountainous area of southwestern China(the upper part is an 8 m high unreinforced shoulder,and the lower part is a 14 m high wrapped geogrid reinforced embankment),the earth pressure boxes and the flexible displacement meters of the reinforcement belt are installed,and one-year field monitoring test is carried out.The vertical soil pressure inside the reinforced soil,the distribution of geogrid strains,and the potential fracture surface form of the reinforced soil retaining wall are deeply analysed.The test result shows that(1)the geogrid can effectually improve the stress distribution inside the reinforced-soil composite body and reduce the vertical earth pressure owing to the net-bag effect of the geogrid grid forms a lifting force in the soil;(2)for the reinforced embankment retaining wall with the upper shoulder filling as the surcharge,the reinforced soil can be divided into"slope load affected area"and"vertical load affected area",both the vertical earth pressure and the strain of the geogrids near the boundary of the 2 areas have peaks;(3)the strain of the geogrids presents a nonlinear distribution along the reinforcement length,the strain of geogrids within 4 m away from the slope surface tends to increase with time after construction,but the maximum tensile strain of reinforcement belt is only 1.32%,and the maximum load is not more than 40 kN/m,which is far less than the ultimate tensile strength(165 kN/m);(4)the potential rupture surface calculated from the actual deformation of the reinforcement belt is consistent with the result calculated by GeoStudio and Geo5,but the result of the numerical calculation is closer to the interior of the reinforced soil than measured one,that is,the overall stability of the embankment is higher,and the numerical calculation

关 键 词：道路工程 垂直土压力 现场试验 加筋土挡墙 筋带应变 稳定性 

分 类 号：U417.11[交通运输工程—道路与铁道工程]