Discrete Element Study on Bending Resistance of Geogrid Reinforced Cement-Treated Sand

Cement-treated sand reinforced with geogrids (CTSGs) has higher bending resistance and toughness than cement-treated sands (CTSs). To explore the reinforcement mechanism of geogrids with different stiffness and layers on CTSGs, three-point bending tests and numerical tests based on DEM are carried out on CTS specimens and CTSG specimens considering different reinforcement conditions. The results show that the geogrids and cement-treated sands have good cooperative working performance. Compared with CTSs, CTSG specimens show better ductility, flexural strength and toughness. The increase in geogrid stiffness and geogrid layers promote the reinforcement effect. On the meso-level, different geogrid stiffness and layers affect the crack propagation speed and distributions of cracks due to the anchorage action of geogrids, resulting in different reinforcement effects. In addition, the layers and stiffness of geogrids affect the evolution of the internal force chains of CTSG specimens. Both the increase in geogrid layers and decrease in geogrid stiffness reduce the average internal force of geogrids and weaken the anisotropy of the normal contact force of the specimens. The simulation results interpret the reinforcement mechanism of a CTSG specimen from crack development and internal force evolution, which can support a mesoscopic supplement to laboratory tests.