Experimental Study On Strength And Deformation Characteristics Of Rockfill By Particle Shape

Rockfill is a kind of coarse aggregate which is widely distributed in nature and rich in reserves.It has excellent compactness,strong water permeability and high shear strength,It is widely used in engineering.Particle shape is one of the main factors affecting the mechanical properties of rockfill materials,affecting the above engineering characteristics.The dense state of the same kind of bulk material with different particle shapes may be different at the same pore ratio,and the compactness is an important factor affecting the shear behavior of the rockfill materials.Therefore,Density ratio and relative density as density control indicators,Study on the effect of particle shape on static deformation,strength characteristics and dynamic characteristics of rockfill particles by triaxial test in this paper.The research contents and main conclusions as follows:(1)Starting from narrow-scale coarse-grained materials,the four kinds of particle sizes,such as 1~2.5mm,2.5~5mm,5~10mm,and 10~20mm,were treated with different degrees of angular wear.Comparison of weighted angular index test of rockfill before and after test.The angularity index can be seen to study the variation of the angularity index of rockfill with the confining pressure.The results show that the rockfill index with the increase of the angular index has a decreasing trend with the increase of the confining pressure.(2)Static shear tests were carried out on three kinds of granitic rockfill materials with different particle shapes.The results show that the particle breakage rate with large angular index is higher than that with small angular index during shearing.The larger the particle angular index of rockfill,the greater the dilatancy of the rockfill due to confining pressure.When the pressure is constant,the peak angle of the rockfill material is larger,and the peak friction angle is larger.However,as the test confining pressure increases,the peak friction angles tend to be equal.(3)The dynamic characteristics of the rockfill were studied.The results show that under low confining pressure,the particle shape affects the shear modulus of the rockfill material to a certain extent,but as the confining pressure increases,the influence of the particle shape decreases.Under the same shear strain amplitude,after changing the shape of the rockfill material,the damping ratio of the rockfill material is not much different from that before the change,and the?~?_d curves of the two rockfill materials almost coincide with the increase of the strain.In general,the shape of the particles has little effect on the damping ratio.