Construction of plastic deformation areas in a homogeneous base of strip foundation

¹ Volgograd State Technical University, 400005, Volgograd, Russia
² Vzlet Branch of the Moscow Aviation Institute (National Research University) in Akhtubinsk, 416501, Akhtubinsk, Russia

^* Corresponding author: boazaritcyn@mail.ru

Abstract

The article discusses two approaches to the question of plastic deformations constructing areas in a homogeneous baseof a strip foundation: a trivial approach based on the use of the Coulomb plasticity condition, and the approach proposed by the authors based on the approximate analytical solution of the theory of elasticity and the theory of soil plasticity mixed problem. It has been established that the “Coulomb” regions, which originally generated under the edges of the strip load, close under the basement as it increases and form a single crescent-shaped plastic area. Plastic areas built on the basis of a mixed solution develop inward and outward from the foundation. Their closure under the foundation occurs at the beginning of the soil uplift process under the foundation, which is accompanied by the appearance of deep heaving zones (Fig. 8; 9). All other things being equal, the “Coulomb” regions are much larger in size and extend to a greater depth than the regions constructed on the basis of a mixed solution of the theory of elasticity and the theory of soil plasticity problem. The elastic soil core, enveloped by “Coulomb” plastic areas, has a shape close to the shape of a half ellipse or a curved trapezoid, and, alternatively, has the shape of an isosceles triangle with concave lateral sides. If we construct the regions of plastic deformations at the base of a strip foundation using the Coulomb plasticity condition, or apply a solution to a mixed problem, then, all other things being equal, the sizes of the “Coulomb” regions, the “rate” of their development and sensitivity to changes in the value of the lateral pressure coefficient of the soil will always be more than in the alternative case. If the value of the ultimate load is taken as its value corresponding to the closure of the plastic areas under the foundation, then the mixed solution of the theory of elasticity and the theory of plasticity of soils problem gives higher (≥500%) the values of the latter. When finding the value of the bearing capacity of the strip foundation base, it is recommended to apply the solutions of the corresponding problems in the elastoplastic (mixed) formulation, since their results, and this has been shown in the work, are in satisfactory agreement with the experimental data.