Abstract: Based on the compression strength tests, bending tests and large scale triaxial tests on cemented sand and gravel (CSG) materials, the correlativity between the strength of CSG materials and the ambient pressure is deduced, and a constitutive equation for the materials during the phases of compression and tension is established combining with the expression of the original tangent modulus and the curve of . According to this constitutive equation, the processes of the bending tests and large scale triaxial tests are simulated. Comparing the test results with those of FEM analysis, we find that they are very similar. It means that the proposed constitutive equation for the CSG material is accurate and reasonable, and it can provide reference for the design and analysis of dams with CSG materials.