CALCULATION MODEL OF DEFORMATION OF THE SOIL FOUNDATION OF A HIGH-RISE BUILDING, TAKING INTO ACCOUNT THE LOADING HISTORY

Abstract

While designing high-rise buildings, it is necessary to take into account the influence of stages of their erection, this is the sequence of loading, on the change in physical-mechanical properties of soils. The calculation of deformations of subgrade is made with due regard for the change in soils properties comparing with the initial (natural) state. On the basis of the results of experimental studies, the authors substantiate the necessity for introducing the new parameter which makes it possible to characterize the mechanical condition of the soil at any stage of loading and can be used for creating calculation models. An analytical diagram of soil deformation in coordinates «σ₁–ε₁» for triaxial compression (where σ₁ – vertical stresses (deviator), ε₁ – linear deformations under the triaxial compression) is adopted as this parameter. The procedure for constructing transformed diagrams of the soil state under the long performance triaxial loading is described. The procedure obtained was approbated when calculating deformations of the foundation base of the high-rise building with due regard for the influence of staging of construction and rheological properties of soils on the change in the base rigidity and, as a result, on the redistribution of stresses among separate elements of the system “subgrade –foundation – upper part of the building.