CURRENT STATE OF THE PROBLEM OF CONTACT INTERACTION OF SOIL BASE AND ROAD SURFACE IN DESIGNING MOTORWAYS

The problem of the bearing capacity of roads and soil bases continues to be relevant to this day due to the growth in the volume of road construction, as well as industrial and civil construction, and the need to design reliable and economical road structures and structures. The assessment of the strength of the bases, the necessity of which is regulated by current regulatory documents, is carried out with varying degrees of reliability based on the use of various approximate methods, solutions to problems of the theory of limit equilibrium, as well as elastic and elastic-plastic problems. Recently, there has been a tendency to increase the role of theoretical research in soil mechanics. The modern methodology for designing bases is based on the idea that the resistance of the base should exceed the stresses that develop in them without excessive safety margins. The paper uses a methodology for calculating the contact interaction of a rigid metal airfield pavement with a soil base, and a comparison with the results of experimental studies is made. The methodology is based on the boundary element method (BEM) and the dilatancy model of nonlinear soil deformation by I. P. Boyko, V. M. Nikolaevsky, (1,2), the method of O. Ilyushin (3) was used, which is based on the use of a linearized system of computational equations. The magnitude of the stresses was determined not only by the instantaneous value of the deformations, as is the case in continuous media, but also by the history of the occurrence of these deformations, which take into account nonlinear plasticity models. According to the formulation of O. Ilyushin, the elastic-plastic medium of the soil is characterized by a “long” memory, that is, the magnitude of the contribution of the previous history at the present moment. The applied value of the mathematical theory of plasticity for the soil base should be higher than the classical theory of elasticity, which is valid for soils at sufficiently low load levels. The purpose of the work is to determine the stress-strain state of the road surface at the entire loading stage. The numerical approach is illustrated by calculations of the stress-strain state of the pavement at each loading step, taking into account the dilatancy properties of the soil and using an elastic-plastic model of the soil base. Comparison of the results of numerical modeling using MGE with the data of experimental studies (9) indicates a fairly good correspondence of these values. Forecasting the stress-strain state of the road pavement has significant practical value.