Study On Particle Breakage Of Coarse-grained Soil During Shearing

Hydro-power resources are a kind of economic and clean renewable energy,which plays an increasingly prominent role in the energy structure of our country.Earth-rock dam is one of the best dam types in hydro-power projects and is widely used in engineering practice.As the main filling material of earth-rock dam,its mechanical characteristics are the key factors affecting the safety of earth-rock dam engineering.With the increase of the dam height,the particle breakage of rock-fill material is more obvious.The particle breakage of rock-fill material is one of the main factors affecting its strength and deformation,so the problem of particle breakage of rock-fill material can not be ignored.At present,domestic and foreign scholars have done a lot of research work on the breakage characteristics of rock-fill materials through laboratory tests and numerical analysis,which provides a reliable theoretical basis and practical guidance for the engineering of bulk materials such as earth-rock dams.However,particle breakage laws of rock-fill material are still unclear and the breakage standard of the rock-fill particles is also inaccurate.The micro-mechanical characteristics of rock-fill affect its macro-mechanical phenomena,but at present,it is impossible to give the basis for accurately obtaining mesoscopic parameters.Single-particle compression test is a key method to study the breakage characteristics of rock-fill.On the basis of previous studies,this paper systematically studies the failure characteristics and the distribution of strength parameters by visual single-particle compression test.In this paper,920 groups of visual-single-particle compression experiments were performed,by which the failure process of different size particles were investigated.It is noted that the destruction process of particles can be divided into four stages and the failure modes can be divided into three types.Moreover,the damage of broken particle increases as the particle size decreases.Comparing visualized and non-visualized single-particle compression tests,it is found that the failure modes of single-particle under visualized conditions are mainly single-stress peak failure types.The single-particle strength parameters of the same size could be accurately simulated by the Weibull model.As the samples increase,the distribution of single grain strength gradually tends to be the normal distribution.Furthermore,gradation distribution of the broken particles is related to the failure mode.Particle gradation of the broken particles,which experienced several peak strengths,conforms to fractal distribution.In addition,the stiffness parameters of basalt particles are analyzed,and it is found that the distribution of single grain linear stiffness also gradually tends to be the normal distribution.