Experimental Study On The Effect Of Particle Arrangement On Mechanical Properties Of Granular Materials

The structural characteristics of soil mainly refer to the geometric characteristics(arrangement characteristics)and mechanical characteristics(connection characteristics)of the particles in the soil.The changes in these two aspects will significantly affect the mechanical characteristics of soil.In this paper,a series of tests were carried out for skeleton particles of different sizes to explore the influence of the arrangement of materials with different sizes on their mechanical properties such as deformation,strength,internal friction angle and cohesion under the condition of conventional triaxial stress.The experimental research work completed in this paper is as follows:(1)Don't consider the effect of factors such as particle shape,compression crushing,the steel balls were chose as skeleton particles,with the three differential sizes(2,2.5 and 3 mm diameters,respectively),meanwhile,bentonite and paraffin wax as filling material.According to the three differential sizes of steel balls,the test plan was designed to three types including 15 kinds of arrangement,and the corresponding samples were made,which has five layers,here,each layer is the same thickness.(2)The stress-strain curves,bulk deformation,shear strength,internal friction angle and cohesive force of skeleton particles with different diameters were obtained under conventional triaxial stress conditions.The main conclusions obtained from the above experiments are as follows:(1)Under the same confining pressure,the stress-strain curves of all samples showed linear changes at the initial stage of shear.After that,the stress-strain curve of the samples showed a transition trend from weak hardening to strong hardening with the increase of confining pressure,and the shear strength increased with the increase of confining pressure.(2)Compared with samples arranged with a single particle size,the internal friction angle of samples arranged in different ways decreases first and then increases with the increase of the particle size of skeleton particles in different layers.(3)In the same arrangement,the particle size has an obvious influence on the shear strength of samples:the shear strength of samples increases first and then decreases with the increase of particle size.(4)Compared with the samples arranged with a single particle size,the internal friction angle of the samples with different arrangements generally presents as follows:As the particle size of the framework particles of different layers increases,the internal friction angle of the samples decreases first and then increases.