On calculation method for dangerously hydrated loess soil with consideration for elastic-plastic soil properties

Abstract

On account of the flow theory of plastically compressible media formulas based on moisture-elasticity and plasticity model for strain analysis of dangerously hydrated loess ground are presented. For derivation of the constitutive equations of moisture transfer P. Ya. Polubarinova-Kochina's formula, Darcy's law for filtration rate and S.F. Averyanov to calculate the parameters at partial water saturation were considered. To estimate stress strain behaviour in subsiding building foundations, a finite element method and iterative methods are applied. The constitutive equation for plastic straining of dilating media is given. At each iterative step a linear problem is solved for soil ground with variable stress-strain properties that depend on a stress-strain state from the previous step. The parameters of matrix for stress-strain properties can be calculated during stabilometrical field tests or by processing the statistical relationship between strain and strength properties. The results of numerical studies and large-scale field tests, performed on experimental area of collapsible loess soil are compared. It is indicated that nonlinearly strained loess foundations of buildings must be regarded under partial saturation conditions, during dangerous hydration process and during stress field and humidity interaction in the course of moisture transfer.