Abstract: To explore the failure process and mechanical properties of soil-rock mixture (SRM) which contains soft and hard rock blocks, a modeling method for SRM is proposed based on the template database of soft and hard rocks. In the particle flow code in two dimensions (PFC2D) the template database of soft and hard rocks is established, which conforms to in-situ structural characteristics. The particle flow models of SRM with different rock block proportions (RBP) are generated, and then a series of uniaxial compression tests is simulated by the particle flow code. The simulation results indicate that the failure of SRM initiates from the interface between rock block and soil, and the separation of soil-rock medium is mostly caused by shear failure. The microcrack grows rapidly at the earlier stage of loading, and the growth rate of microcracks slows down at the middle and later stages, while the macroscopic deformation gradually becomes significant. The uniaxial compressive strength of SRM decreases with the increase of RBP. The rotation and lateral movement of rock block can aggravate the integral destruction of SRM. At a certain RBP, the uniaxial compressive strength of SRM shows a decreasing tendency with the increase of soft rock block proportion. The rupture rate of specimen and the rupture degree of single soft rock granule are maintained at a high level after the test, and the rupture of soft rock granules is an important reason for the decline of SRM’s uniaxial compressive strength.

Key words: rock and soil mechanics, template database, mesoscopic damage, rock block proportion