Research purposes:Soil-rock mixture(SRM)is characterized by heterogeneity,nonuniformity,discontinuity and remarkable structural effect,and its physical and mechanical properties are very complex.In order to explore the influence of rock block proportion on the shear properties of soil-rock mixture,a discrete element numerical model of soil-rock mixture was established based on the real shape of rock blocks and the reverse reconstruction of rock block using digital image method.On this basis,the three-dimensional discrete element direct shear tests of six rock contents samples under four different normal stresses were carried out.Research conclusions:(1)The shear stress-shear displacement curves can be divided into four phases including elastic,initial yield,peak strength and residual strength.(2)In the process of shearing,the rotation of block stones has obvious"gear driving effect",the movement of soil particles has an obvious"rock around"phenomenon,and the movement of particles has an obvious vortex shape.(3)The force chain is mainly distributed along the angle between shear force and normal force.With the increase of rock content,the angle of the force chain towards the horizontal shear direction increases.(4)The evolution of shear plane mainly goes through micro crack stage,shear plane penetration stage,and shear band widening stage.The width of shear band increases with the increase of rock content,and gradually deflects counterclockwise.(5)The shear strength of soil-rock mixture increases with the increase of rock content.Through the fitting formula,the cohesion and internal friction angle are exponential functions with the rock content.(6)The research results can provide reference for the determination of mechanical parameters in the design and construction of SRM engineerings.
关键词
土石混合料/剪切特性/真实块石形状/直剪试验/离散元
Key words
soil-rock mixture/shear properties/real shape of rock blocks/large-scale direct shear test/discrete element
维普
万方数据