Abstract: The direct shear test is the most common laboratory test method in the geotechnical engineering to estimate the soil shear strength indices. Currently, it is widely used in the engineering projects. To evaluate the control factors for the direct shear test and improve the quality of testing, this paper establishes a two-dimensional numerical model of the direct shear test by using the discrete element method. The conclusions are as follows: (1) The aspect ratio of the shear box will affect the test value of the shear effect; More accurate shear effect test values can be obtained by using a shear box with a smaller aspect ratio; (2) The vertical and horizontal normal stresses of the shear band are equal, so the direction of the principal stress and strain rate is coaxial. Therefore, the direct shear test cannot carry out non-coaxial correlation analysis. The results of this paper provide reliable data support for improving the quality of the direct shear test.

Key words: Direct Shear Tests, Discrete Element Method, Quality Control