STUDYING THE PILE-GRAVITY STRUCTURE OF A MOTORWAY UNDER DEGRADATION OF A FROZEN FOUNDATION SOIL
In this article, one of such decisions is considered on the example of a section of the “Amur” route Chita - Khabarovsk, in the base of which there is a degrading permafrost and deformations of the soil body together with the existing structure - the roadbed of the road section. The proposed method implies the joint operation of a holding pile-gravity structure and a geocomposite grillage from an integral geogrid. Despite the widespread use of such structures during construction on disperse soils [1, 2], the work of such on frozen soils remains poorly understood. For the possibility of evaluating and comparing strength and deformability indicators, computational and theoretical studies have been performed both for the existing structures of the road and the state of the foundation, and for designed structures. In order to achieve the goals set in the technical task, the geotechnical software complexes FEMmodels, Termoground and Plaxis V82D were used. They are able to simulate the work of the facilities in its stress-strain state, the thermodynamic processes in the annual freeze-thaw cycle and evaluation stability of soil bodies and structures. To describe the construction work on weak thawing substrates, an elastoplastic model with a limiting surface, described by the Coulomb-Mora criterion, was used. The choice of this model was due to the fact that its parameters can be taken from existing materials of standard engineering and geological surveys. In this formulation, numerical calculations are in good agreement with the traditional engineering methods for calculating the sediment and allow us to describe with sufficient accuracy the deformation of structures on weak thawing grounds. The performed analysis of the proposed solution showed high efficiency and operational reliability of soil structures developed using the properties of modern geosynthetic materials in combination with traditional materials and production technologies.