Numerical analysis of vertical stress distribution in the direct shear box devices

When determining the soil strength parameters with direct shear box devices, the values of the parameters are influenced by devices construction. In assessing this effect, it is necessary to know the magnitude of the vertical stresses and the nature of the distribution in the shear plane. The soil shear resistance depends on the size of the vertical stresses and the nature of the distribution in the shear plane. These factors depend on the interaction of the soil with the vertical walls of the device, i.s. friction between the soil and the walls. At the beginning of the test, the vertical stresses on the shear plane will be lower than the added pressure at the top of the sample, however the stresses increases due to dilation during the test. Before the test ends, the stresses in the shear plane will be higher than at the top of the sample. The article has presented the nature of the vertical stresses distribution on a horizontal plane when using direct shear box device. The analysis was performed using the PLAXIS 3D software.