土工格栅加筋包边填砂路堤模型试验研究

为探究包边填砂路堤荷载作用下的极限承载力特性、破坏形态规律及加筋性状,设计了土工格栅加筋包边填砂路堤结构,改装美国GCTS公司的USTX-2000动静三轴加载装置进行加载,通过改变加筋层数、筋材布置长度及包边土厚度对土工格栅包边填砂路堤进行一系列试验。对不同工况下包边填砂路堤的极限承载力、封层及坡面法向累积变形、位移变化进行研究。试验结果表明:土工格栅加筋和增加包边土厚度可以显著提高包边填砂路堤的极限承载力,并能减小封层中、封层右及坡顶、坡中的法向累积变形;无筋路堤的滑动面在路堤内呈折线状且并未通过坡脚侵入地基,在坡顶的黏土和砂芯交界处产生最大位移;土工格栅加筋及增加包边土厚度可以使滑动面向路堤内部迁移但形态不变,且最大位移处向路堤内部迁移。

Model Tests on Geogrid-reinforced Sand-filled Embankment with Cover Layer

Sand-filled embankment with cover layer is an important embodiment of the green road concept. In order to investigate the ultimate bearing capacity characteristics, failure morphology and reinforcement behavior of sand-filled embankment under load, we designed a model of geogrid-reinforced sand-filled embankment, and modified US GCTS’s USTX-2000 dynamic and static triaxial loading device for loading tests on the model with varied reinforcement layer, reinforcement length, and cover thickness. According to the obtained results of ultimate bearing capacity, normal cumulative deformation and displacement change of the embankment slope and cover layer, we concluded that the geogrid reinforcement could significantly improve the ultimate bearing capacity of the sand-filled embankment and reduce the normal cumulative deformation on the right and middle side of the embankment cover as well as on the top and middle of the slope; so does increasing the cover thickness. The sliding surface of unreinforced embankment was a broken line in the embankment and did not invade the foundation through the slope toe; and the maximum displacement occurred at the boundary between the clay and the sand core at the top of the slope. Geogrid reinforcement and increasing the thickness of the cover layer soil could make the sliding surface and the maximum displacement move towards the interior of the embankment without changing the shape.