Study On Mechanical Properties Of Soil And Rock With Long Axis Orientation Angle Of Response Block Stone

There have been many research results on soil-rock mixtures in the current research,and the research results are particularly rich in the types of stones,stone content,stone particle size,shear rate and spatial distribution.There are still deficiencies in the study of the internal soil-rock mixture,especially in the study of the direction of the block stone,such as the directional angle of the block stone,which angle is the most sensitive to the mechanical properties of the soil-rock mixture.Anisotropy has a great influence on the mechanical properties of soil-rock mixtures,which mainly includes two types: initial anisotropy and stress-induced anisotropy imposed afterward.For the study of anisotropy,scholars at home and abroad are more concentrated in the stress-induced anisotropy applied in the day after tomorrow.In this paper,the influence of block sedimentary direction on the mechanical properties of soil-rock mixture belongs to the initial anisotropy.In order to minimize the impact of material composition differences,each group of test samples were taken from the same location,the same material,improve the accuracy of the test.Based on the repeatability of the test results under the same working conditions,the influence of the orientation angle of the block stone on the mechanical properties of specific soil and rock is analyzed emphatically through the large-scale triaxial test in the laboratory.The results obtained by PFC2 D numerical simulation are compared with those obtained by the test,so as to obtain the influence of the orientation angle of the block stone on the mechanical properties of soil and rock.On the premise of ensuring the accuracy of the test instrument,based on the large-scale triaxial test,the influence of the direction of the block stone on the stress-strain curve,shear strength,initial elastic modulus and dilatancy of the soil-rock mixture is studied by changing the direction of the block stone in the soil-rock mixture.The main work and research conclusions are as follows :(1)The directional angle distribution of rock blocks has a significant effect on the mechanical properties of soil-rock mixture.When the strain of the soil-rock mixture with and without the directional angle distribution of the block stone is below20 %,the stress-strain curve without the directional angle distribution of the block stone first increases rapidly and then tends to be stable,and the stress-strain curve with the directional angle distribution of the block stone maintains continuous growth.The shear strength of soil-rock mixture with directional angle distribution is significantly lower than that without directional angle distribution,and the shear strength is: no directional angle> 0°> 30°> 60°>45°.The initial elastic modulus decreased first and then slowly.(2)The mechanical behavior of soil-rock mixture affected by orientation angle of block stone is higher in non-viscous matrix than in viscous matrix.The stress-strain curve of clay matrix soil and rock increases sharply under load.The non-cohesive matrix increases slowly at first and then quickly,and then remains stable.The non-cohesive matrix soil and rock reaches the peak stress earlier.The shear strength of soil-rock mass first decreases and then increases with the increase of the block orientation angle,and the minimum value is taken when the block orientation angle is 45°.The initial elastic modulus of soil-rock mass is greatly affected by the matrix viscosity,and the non-viscosity matrix soil-rock mass is greater than the viscosity matrix soil-rock mass.(3)The orientation angle of rock blocks determines the failure mode of soil-rock mixture,and the rotation and movement of rock blocks are affected by the aspect ratio of rock blocks and the viscosity of matrix in the meso-scale.By increasing the simulation conditions through the numerical model,the failure mode of soil-rock mixture and the rotation of internal block stones are obtained.The failure mode of samples under different substrates is X failure,but there is a slight difference.With the increase of block orientation angle,the rotation angle of block increases first and then decreases.