土工格栅加筋粗粒土的加筋影响带研究  

Study on the Effected Strip of Geogrid-reinforcement in Granular Soil

作　　者：胡幼常[1] 田树林 HU Youchang;TIAN Shulin(School of Transportation and Logistics Engineering,Wuhan University of Technology,Wuhan 430063,China)

机构地区：[1]武汉理工大学交通与物流工程学院,武汉430063

出　　处：《武汉理工大学学报（交通科学与工程版）》2021年第6期1133-1139,共7页Journal of Wuhan University of Technology（Transportation Science & Engineering）

摘　　要：为了探寻土粒级配、土工格栅横肋厚度等对加筋影响带厚度的影响规律,选定一种双向土工格栅,制作出具有3种不同横肋厚度的筋材试样,通过特制的可视化拉拔仪,分别在6种不同级配的粗粒土中,完成了不同法向压力下的多组拉拔试验.借助预埋于土中的位移观测点,观测了筋-土界面及界面以上不同高度处的土粒位移.根据土粒横向位移沿高度的分布规律,判别出各试验工况下的加筋影响带范围.经统计分析,得到了加筋影响带厚度δ与土粒平均粒径d_(50)、不均匀系数C_(u)、曲率系数C_(c)和土工格栅横肋厚度t之间的近似关系式.该公式较全面地考虑了粗粒土的级配、粒径大小对影响带厚度的影响,并将土工格栅横肋厚度的影响也纳入其中.试验结果还表明,土工格栅对粗粒土的间接加固作用在筋-土界面处最强,并随着离筋-土界面垂直距离Y的增大而逐渐减弱.据此,针对加筋间距与加筋影响带厚度的相对大小,分析了不同情况下加筋影响带内土体抗剪强度增长量随Y值的变化规律,并提出了加筋土坡稳定性分析的“改进影响带法”.In order to explore the influence law of soil grain gradation and the thickness of transverse rib of geogrid on the thickness of reinforced influence zone,a kind of bidirectional geogrid was selected,and three kinds of reinforcement samples with different cross rib thicknesses were made.Several groups of pull-out tests under different normal pressures were completed in six kinds of coarse-grained soils with different gradations by a special visual pull-out apparatus.With the help of displacement observation points embedded in the soil,the displacement of soil particles at different heights above the rebar-soil interface and the interface was observed.According to the distribution law of lateral displacement of soil particles along the height,the range of reinforcement influence zone under each test condition was identified.By means of statistical analysis,the approximate relationship was obtained betweenδ,the thickness of the reinforcement-effected strip,and the average diameter of soil particles,the uniformity coefficient,the coefficient of gradation and the thickness of geogrids transverse rib.In this formula,the effects of the grain gradation and the particle size of the granular soil onδare considered,and the effects of the transverse rib thickness of geogrid are also taken into account.The test results also show that the indirect reinforcement effect of geogrid on coarse-grained soil is the strongest at the interface between reinforcement and soil,and gradually decreases with the increase of the vertical distance Y from the interface between reinforcement and soil.According to the relative size of the reinforcement spacing and the thickness of the reinforcement influence zone,the variation law of the shear strength of soil in the reinforcement influence zone with Y value under different conditions was analyzed.On this basis,the“improved influence zone method”for stability analysis of reinforced soil slope was put forward.

关 键 词：加筋影响带 厚度计算公式 抗剪强度增长规律 土工格栅 粗粒土 

分 类 号：U416.12[交通运输工程—道路与铁道工程]