The analysis of modern design methods for mounting the pits side indicates the difficulty in predicting the magnitude and distribution of the load on supporting flexible walls. Existing normative methods for calculating supporting structures of foundation pits are generally aimed at ensuring their durability and stability. Using these methods, load on the fence, depending on the strength parameters of the soil, determine shifts, bending moments, transverse and longitudinal forces, and calculate the parameters of the fence it is necessary to ensure the strength of the structure. The necessary depth of its foundation determines the condition of the stability of the fence. The generalization of knowledge in this area, as well as the development of a mathematical model for numerical implementation of the considered problem, will increase the level of rational consolidation of deep pits. In the course of the study, a mathematical model was developed from the following types of mounting: drill piles, tangent drill piles, "Larsen" tufts, monolithic "wall in the ground" in the GeoWall software complex, which is widely used to calculate the strength and stability of supporting walls of foundation pits of different type. According to the results of computer simulation, the largest horizontal deformations are inherent to a type-L4-type tongue mount, which is about 8 cm. The maximum deformation patterns of the drill piles and tangent drill piles are quite similar, respectively; they are 4.1 and 3.9 cm. Therefore, for further the study was adopted as a monolithic "wall in the soil", as the depth of the development of the pit horizontal deformations increase in the range from 0.3 cm to the maximum displacement of 2.6 cm. Maximum vertical displacement of compression is about 0.5 cm.