Abstract: To investigate the bearing performance and deformation characteristics of geogrid-reinforced sand soil foundation under the action of dynamic loading, the static and dynamic load failure tests on the pure-sand foundation and geogrid-reinforced foundation were carried by using a self-designed large scale foundation model test device of 300 cm (length)×160 cm (width)×200 cm (height). The variation laws of foundation bearing capacity, foundation settlement, foundation soil pressure, dynamic acceleration response and geogrid strain were analyzed. The bearing capacity and deformation characteristics of reinforced sand foundation under dynamic load were revealed, and the influence of static and dynamic loads on the bearing capacity of reinforced foundation was compared and analyzed. The results showed that the bearing capacity of the monolayer reinforced foundation was improved by 1.12 times as compared with the pure-sand foundation, and the axis settlement of the foundation was reduced by 24%. Moreover, the anti-deformation ability of reinforced-foundation soil was significantly improved compared with pure-sand foundation. The reinforcement changed the failure mode of the foundation, the failure mode of pure-sand foundation was the punching-shear failure, whereas reinforced foundation was whole shear failure under dynamic loading. The existence of the reinforcement had obvious diffusion and attenuation effect on earth pressure and the acceleration peak respectively, which could effectively reduce the transient deformation of the reinforced-soil under dynamic loading.

Key words: geogrid, reinforced foundation, interface interaction, bearing characteristic, dynamic loading test