Experiment of geosynthetic tensile strength in soil- geosynthetic interaction by pull-out test
A.beyranvand, S.H. Lajevardi, M.M.H Hazaveh
Soil reinforcement has a long history to improve its shear and tensile strength. The new way of soil reinforcement was developed by Henry Vidal in France (1960). In recent years, the use of geosynthetics has been increased to reinforce the soil structures. Due to the increasing use of geosynthetics, it is necessary to examine the stability of the reinforced soil structures by geosynthetic and also their analysis for internal and external stability. The use of reinforced soil by geogrid is preferred in economic and operational terms than the other methods for the earth structures stability. In this research, the soil-geogrid interaction parameters were studied in pull-out mode and a large-scale laboratory pull-out apparatus was used to study the geogrid tensile strength effect on the soil-geogrid interaction and five types of geogrids with different tensile strength were used. The results of the experiments showed that if the vertical pressure on the specimen is zero, all the geogrids are extruded out in the pull-out mode and do not rupture. Vertical pressure has a great effect on the increase of the t pull-out strength and when the tensile strength becomes higher, the greater vertical force is required on the surface of the sample in the pull-out box, so that its pull-out strength becomes active entirely. By increasing the tensile strength of the geogrid, the pull-out force of the geogrid becomes greater and the displacement of the geogrid sample is reduced inside the pull-out box. The results showed that by compressing the soil sample and placing it up and down the geogrid plate, the pull-out force is increased.