The Influence of the Negative Properties of Heaving Soil on the Stability of Frame-Rod Structural Systems

Abstract

This article discusses the influence of the negative properties of heaving soil on the stability of frame-rod structural systems during the operation of buildings and structures. It is known that the loads and influences arising during the operation of buildings and structures can lead to loss of stability of both an individual element and the entire structural system as a whole. It is extremely difficult to accident-free work operation of buildings and structures, the foundation layer of which are heaving soils. Therefore, it is necessary to develop a methodology for determining the critical stability parameters of frame-rod structural systems that takes into account the heaving properties of base soils. In the process of loss of stability, elements of frame-rod structural systems under the influence of force factors due to the influence of constrained conditions can experience both passive and active bifurcation. With the manifestation of the negative properties of heaving soils, vertical deformations of the base occur, which can lead to a change in the type of bifurcation of both an individual element and the entire structural system as a whole. Based on the assumption that the element will pass from passive bifurcation to active at the moment when the work performed by internal forces is compensated by the work of the heaving forces, an expression is obtained to determine the critical deformation of the base soil. A statically indefinable single-span frame is considered, the right strut of which is loaded with force P and the left one with force αP. Using the displacement method, the critical stability parameters of the specified rod system were determined before and after the manifestation of the negative properties of the base soil. Based on the numerical analysis, it was concluded that the right pillar of the frame loses stability actively, involving the left one in the general bifurcation. After manifestation of the negative properties of the base soil, the type of bifurcation of the frame elements changes, leading to significant changes in the stability parameters. In this case, the critical deformation of the heaving linearly increases with an increase in the geometric dimensions of the frame and decreases with an increase in the load application coefficient α at 0,6<α<0,8 and 1,0<α<1,1. In the range 0,8>α> 1,0, these parameters are directly proportional.