| The selection of rock similar material is the key to the success of physical modelling experiment.It is difficult to simulate the dynamic fragmentation process of rock avalanche and the movement process of sliding body with the water environment in experimental modelling due to the high strength and poor water stability of rock similar materials.Thus,we choose six raw materials to formulate similar materials.The six raw materials are barite,quartz sand,gypsum,sodium metasilicate,sodium carboxymethyl cellulose,and water content.The physical and mechanical parameters of similar materials were measured by uniaxial compression test and direct shear test.Analyzing the relationship between each factor and each physical and mechanical parameter and the rock similar material with appropriate ratio is determined to be used for model test.The main research results are as follows:(1)In low strength and high brittleness rock similar material ratio test research.The results show that: the uniaxial compressive strength is between 0.12 and 1.47 MPa,the elastic modulus is between 25.51 and 148.12 MPa,the cohesion is between 1.63 and 87.39 k Pa,and the internal friction angle is between 22.70° and 35.89°.The ratio of aggregate and cement controls the shear strength of rock similar material.The proportion of sodium carboxymethyl cellulose has the greatest influence on uniaxial compressive strength,modulus of elasticity,cohesion and brittleness index.The content of mixing water mainly affects brittleness index.The content of glycerine has the greatest effect on the elastic modulus.The rock similar material has the physical and mechanical properties of low strength and high brittleness,which is suitable for the simulation of the clastic process of high-speed remote landslide.At the same time,similar rock materials have good homogeneity and stable mechanical properties.However,the similar rock material does not have water stability and immediately disintegrates when it meets water,so it is not suitable for the rock high-speed remote landslide physical model test under water environment.(2)In water stable and low strength rock similar material ratio test research.The results show that: the internal friction angle is 24-35°,the cohesion is 0.017-0.190 MPa,the uniaxial compressive strength is 0.277-0.845 MPa,the elastic modulus is 63.409-193.080 MPa,the brittleness index is 0.063-0.190,the water stability coefficient is 0.202-0.786.The ratio of aggregate and cement controls the elastic modulus and brittleness index.The ratio of barite to quartz sand have the great effect on the angle of internal friction.The ratio of sodium silicate to Sodium silicate has the greatest influence on the water stability coefficient of similar rock materials.The proportion of sodium carboxymethyl cellulose has the greatest influence on uniaxial compressive strength,modulus of elasticity,and angle of internal friction.The content of glycerine has the greatest effect on cohesion.The rock similar material has the characteristics of low strength,high brittleness and good water stability,which is suitable for the simulation of high speed remote landslide clastic process in water environment.The material not only has the characteristics of breakability and good water stability in laboratory scale,but also has good uniformity,and the mechanical properties are relatively stable in indoor environment.But because the raw material contains sodium silicate,resulting in the rock similar with the nature of rapid molding,so the rock similar material can not be prepared in large quantities at the same time,otherwise it is easy to cause the sample in the mold before consolidation.(3)In the study of the effect of water level depth in accumulation area on the landslide movement process,two rock similar materials,namely low strength and high brittleness rock similar material and water stable and breakable rock similar material,were selected to carry out high-speed remote indoor physical model test of landslide.It is found that with the increase of the water level depth in the accumulation area,the longer the movement time of the slider is,the more distant the slider is,and the detrital degree in the slider decreases obviously.The test results further prove the detrital characteristics and water stability of similar rock materials,which can be applied to the high-speed remote landslide physical model test. |
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