Stability analysis of soil-rock mixture slope based on 3-D DEM

Abstract:

To investigate the stability and failure mechanism of soil-rock mixture (SRM) slope, three-dimensional discrete element modeling method (3-D DEM) models for meso-structure of SRM slopes were constructed based on the basic principle of geotechnical centrifugal model test and the developed 3-D DEM for irregularly shaped rock blocks and SRM. Then, particle flow code strength reduction for slope stability analysis was introduced and a novel identification method for slope failure based on the energy evolution was developed. Finally, effects of rock block proportion, rock block shape, spatial structure, and spatial configuration on the stability and failure model of SRM slope were analyzed. Results show that the safety factor is increased with increasing rock block proportion. Multiple zigzag sliding surfaces by passing the rock blocks occurred in the SRM slope model, and some big rock blocks located in the slope toe caused an obvious shift of the shear outlet. The safety factor of the SRM slope is gradually increased when the rock blocks changed from spheres and pebbles to gravels. The failure mode of dual structural slope model with a thick overburden SRM and a low gradient or single SRM slope is mainly the cambered sliding that occurred within SRM, whereas the dual structural slope model with a thin overburden SRM and flat bedrock generally have wholly sliding along the bedrock surface. With the spatial configuration of SRM slope from strip type and outlet-open type to outlet-locked type, the safety factor is gradually increased, and the outlet-locked slope have significant arch-supporting effect, which is more obvious when the rock block proportion is larger.