JUSTIFICATION OF THE CHOICE OF THE MODEL OF THE BUILDING'S BASE AND FOUNDATION DURING ITS REINFORCEMENT WITH MICROPILES

Abstract

Purpose. Based on the analysis of the existing experience, to justify the choice of the model of the base and foundation of the building during its reinforcement with micropiles. Such a methodological step will make it possible to adopt a base model, which more fully corresponds to the interaction of micropiles, the foundation of a certain stiffness and the variation of their parameters for further research. Methodology. Foundations, including those reinforced with micropiles, are designed in such a way that the load on the foundation does not exceed a certain limit, which allows calculations for deformations in the compaction phase. To solve the problem, the analysis of the method of general elastic deformations of the base, developed using the hypothesis of an elastic half-space, was carried out. The inclusion of an elastic half-space in theoretical constructs is based on clear and well-established solutions of the theory of elasticity and, more broadly, the mechanics of a solid medium. Also, the considered method is based on limiting the zone of the deformable base (hypothesis of a layer of finite thickness). The cases of application of these hypotheses for the design and calculation of foundations, taking into account their interaction with the foundation were generalized. Findings. It was determined that the elastic layer hypothesis is a more fruitful hypothesis both for foundations in general and for the case of their reinforcement with micropiles. On its basis, it is justified that the finite-element models of the foundation with micropiles and the soil base should have defined limits, which, first of all, allow free deformation of the «foundation – base» system, and, secondly, have dimensions that can be subjected to calculation on a personal computer. Originality. It consists in substantiating the foundation model based on the hypothesis of a layer of finite thickness as the most suitable for numerical experiments using the finite element method. Practical value. It consists in obtaining a justified thickness of the final layer, which is equal to 5 … 6 values of the length of the micropile. It is this thickness, on the basis of which the dimensions of the finite-element model are chosen, that allows the free formation of the stress-strain state of the model and does not contradict the existing requirements for determining this parameter.