Load-Bearing Capacity Analysis on Rubber-Sand Mixture Cored Composite Block as Low-Cost Isolation Bearing for Rural Houses Based on DEM Simulations

In previous research, the group proposed a low-cost seismic isolation device, the rubber sand core composite block (RSMCB). This study builds upon newly conducted experiments to elucidate the vertical bearing capacity of the RSMCB through discrete element method (DEM) simulations. The effects of rubber content, cover plate forms, dimensions, and sidewall lengths are examined. A formula for vertical bearing capacity was derived from experimental and simulation results. The main findings are as follows: (1) The RSMCB exhibits nonlinear behavior under vertical loads. Sand and rubber particles have rough surfaces, leading to strong interparticle friction. This friction facilitates the formation of robust force chains. When the applied force is within the friction angle range, particles enter a self-locking state, ensuring stability and enabling RSMCB to withstand substantial vertical loads. (2) Higher rubber content increases pores in the RSMCB, resulting in greater vertical displacement of the cover plate. Employing a larger cover plate mitigates the vertical displacement. (3) When utilizing a square straight-cylinder cover plate for the RSMCB, its load-bearing capacity is increased by 187% compared to a square cover plate. (4) At a rubber content of 50%, minimal contact occurs between sand particles. Rubber particles control overall strength. (5) Theoretical formulas can be employed directly to ascertain the bearing capacity of the RSMCB.