DEM Simulation of Pullout Tests of Geogrid-Reinforced Gravelly Sand
Geogrid has been widely used to stabilize the earth structures and the interaction behavior between geogrid and its surrounding backfill soil is the key issues for this reinforcement to develop its reinforcing effects. In this study, a two-dimensional discrete element model was built by PFC2D to simulate the pullout behavior of uniaxial geogrid-reinforced granvelly sand under tensile loads. The backfill soil was modelled as unbonded particles with linear contact stiffness model and the geogrid was modelled as bonded particles with piecewise linear model which was developed based on parallel bond model and was applied in every two adjacent two particles of geogrid. This numerical model was firstly calibrated and verified against the results obtained from laboratory experiments of geogrid tensile tests and direct shear tests of sand. Then, two different kinds of soil particle distribution of gravelly sand were simulated to study the effects of gradation on the pullout responses of displacement distribution along the geogrid, normal stress distribution in the geogrid plane and pullout force at different clamp displacements. The results showed that the pullout force of geogrid embedded in well graded gravelly sand increased with increasing the clamp displacements and was greater than that of geogrid embedded in poorly graded gravelly sand at larger clamp displacements.
KeywordsGeogrid Pullout tests Gravelly sand Gradation Discrete element method
The support from the Key Research and Development Project of Chinese Ministry of Science and Technology under grants 2016YFE0105800 is gratefully acknowledged.
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