عنوان مقاله [English]
In recent years, application of rubber-soil mixtures has been widened in civil engineering problems. As a consequence, a lot of studies are performed in order to understand the mechanical behaviour of such mixtures. One of the research tools for studying the behavior of such mixtures is the utilization of numerical methods. Among them, Discrete Element Method (DEM), which is specifically denoted to the simulation of granular media, is used in this paper by using DISC code. To this end, several samples, including clean sand as well as sand-rubber mixtures with different portions of rubber (10\%, 20\%, 30\%, and 50\%), were considered. The samples were loaded by two stages including isotropic compaction under confining pressures of 50, 100, 200, and 400 kPa as well as deviatoric compression loading. The second stage was performed in such a way that the samples were loaded in vertical direction by displacement-control procedure; at the same time, the lateral stress (in horizontal direction) was kept constant. The simulations were considered in two-dimensional space with circular particles for both sand and rubber. Numerical simulations showed that the increase in rubber content of the samples caused a decrease in the stiffness of the mixtures continuously, while the shear strength raised up to rubber content of 30\%, and then it decreased slightly. By comparing the results with those of experiments, it is understood that this occurrence is due to the assumption by which, the geometry of
particles was considered as circular. The results show that the increase in the confining stress level causes an increase in the initial tangent stiffness of the samples. However, the increase in rubber content still has decreasing effect on the initial tangent modulus. In the present study, the comparison of simulation results with those of experiments reveals that there is good agreement between the observed trends in the mechanical behaviour in a qualitative manner.