Effect of some test conditions on pull-out behaviors of interface between geogrids and compacted expansive soils
Cai Jian-tao · Rock and Soil Mechanics · 2008
Expansive soil reinforced with geogrids to construct embankment,or to strengthen and protect the excavated expansive soils and rock slope is successfully applied;and this techonology has significant values both in the prevention of geological disaster and project construction.So a filling soils with dimensions of 600 mm×600 mm×600 mm laminated shear test apparatus is employed to carry out a series of pull-out tests,with HDPE uniaxial geogrid,and the weathered expansive marlite in Xinxiang,the middle route of the South-to-North Water Transfer Project.The factors of test conditions effecting the pull-out behaviors of the interface,such as distance between geogrid and the test box wall,the pull-out velocity,and the upper load are studied.Results show that the peak value of pull-out force,the strength and tangent rigidity of the interface are not evidently effected by the distance between geogrid and wall of the test box under the undrained conditions.The pull-out force increases rapidly with the increase of pull-out velocity,and the peak value of pull-out force and the interface strength is greater.The geogrid deformation and the relative displacement between geogrid and soils differ with the difference of the upper load and pull-out forces.The heterogeneous degree of friction of the interface distribution along the embeded length of geogrid differs with the different upper load;and this can lead to the abnormal behavior that the average friction of the interface is bigger even when the upper load is smaller.