Stress in the Two-Layer Soil Under the Building

Abstract

In recent times, the mechanical properties of the surface layer have changed in some areas of the surface of the grant. The mechanical properties of the soil along its thickness become discretely variable. The soil ceases to be monolithic. It becomes two-layered. The conditions for the construction of structures whose foundation height does not exceed the thickness of the surface layers should take into account the latter. The purpose of the work is to substantiate and formulate an algorithm for determining the parameters of the stress-strain state of the soil of a two-layer structure and to establish the dependence of soil surface deformations on the mechanical properties of the formed soil layers. The soil of the two-layer structure is considered as a two-layer body, of unlimited height, of limited dimensions in the orthogonal direction. An external normal load acts on the soil. Soil layers were considered linearly elastic, isotropic with excellent mechanical properties. It was taken into account that the contact surfaces of the layers deform together without the formation of gaps and overlapping. The interaction forces of the layers are equal and oppositely directed. The indicators of the flat stress-strain state of the layers were determined by the method of the classical linear theory of elasticity using the biharmonic Ery stress function. We took into account the load of the limited part of the outer surface of the first layer or its movement under the action of the structure and the conditions of compatibility of deformation of the layers. Formulated linear systems of algebraic equations. By solving it, the unknown coefficients of the stress function were determined. The dependences of the parameters of the stress-strain state of the layers of the two-layer soil were formulated. It was established that the change in the compression modulus of the surface layer of the soil significantly affects the deformation of the soil surface under the action of external normal load and is practically independent of other mechanical characteristics of the surface layer of the soil.

Keywords

• two-layer soil
• biharmonic stress function
• mechanical properties of the material
• stress-deformed state
• load