抄録
This paper presents the results of direct shear tests on sand samples reinforced by inclusions. A large direct shear apparatus (1 m3) was used for the experiments in conjunction with Leighton Buzzard sand and different types of grid and sheet reinforcement. The results showed that the presence of the reinforcement layer inclined to the central plane of the box caused a significant reduction of shear strains developed along the central region of the sample and increased the overall strength of the sand. High normal stresses on the reinforcement plane prevented bond failure between soil and reinforcement, which limits the application of direct shear tests with inclined reinforcement as a way of measuring bond strength between soil and reinforcement. At large shear displacements the performance of polymer reinforcement was enhanced by the favourable deformed shape of the reinforcement. At peak shear load the deformed shape of the reinforcement had little effect on the test results. This suggests that the assumption of a deformed reinforcement layer at the interception with the failure surface may be unrealistic when analysing reinforced soil structures at peak conditions by limit equilibrium methods. As a consequence of the latter, it was also observed that, for the range of values tested, the influence of the reinforcement bending stiffness was negligible.
