Study On Physical And Mechanical Properties Of Coarse - Grained Soil

In recent years, with the large increase in geotechnical engineering projects, the water sector, transportation industry and construction industry have been rapidly developed. Because of coarse-grained soil has many engineering and construction advantages, such as large filling density, small subsidence deformation, strong water permeability, high bearing capacity. It has been widely used in embankment dams, highways and railways. The research of physical and mechanical properties of coarse-grained soil material has the application value and academic significance.Relied on a large number of laboratory tests result of triaxial shear strength, seepage properties, compression deformation properties of mentor’s research projects and other people’s tests, the physical and mechanical properties and their change rule has been analysed, model parameter calculation has been studied. This article carries out specifically includes the following aspects:1. By the test results of triaxial shear tests, the variation of the stress-strain curve in different densities and different confining pressures has been analysed. Relaying on the analysis of Duncan-Chang model, its problems has been studied, then a new improved model with eleven parameters has proposed. The improved model results show that it can better show the properties of coarse-grained soil, the calculation precision of body strain characteristics of coarse-grained soil and Duncan-Chang model can be improved.2. By the test results of seepage tests, the influence of seepage directions, soil particle size, effective particle size and void ratio on coefficient of permeability of coarse grained soil has been analysed, the mechanism of the various factors that affected the permeability coefficient of coarse grained soil has been explored. It shows that influence on permeability coefficient of grain size characteristics, porosity ratio on coarse granular soil can be expressed with two permeability model based on the Terzaghi and Hazen.The permeability models established are more perfect and has higher precision.3. By the test results of compression deformation tests, the influence on compression coefficient of the water content and degree of compaction on void ratio, the problems in the calculation methods of consolidation coefficient in specification has been analysed. The calculation methods of consolidation coefficient been improved and a method of curve-fitting method is presented.