Roman Melnikov’s research while affiliated with University of Tyumen and other places

The paper presents a system for the safe construction assessment of a building and its structures with a developed substructure and with a crucially changed superstructure at the late stage of construction under the conditions of the completed substructure at the early stage of construction. The main specific feature of above-mentioned construction is to ensure the continuity of the superstructure erection in case of the high increased loads on the foundation (mainly on the foundation slab) until it is strengthened. All values of the settlements and deformations of the building were find by using the verified program “STARK ES” and due to the results of the geotechnical monitoring. The paper proposes a verification system for acquired data proceeding to the monitoring and calculated values of settlements and deformations of the foundation slab which ensure the operational safety using the convenient "traffic light" method and the instructions for its successful use.

When erecting high-rise buildings, weak underlying soils cause a number of problems in design and construction. In order to ensure the required non-exceedance of the ultimate limit settlements, the combined strip pile foundation has been developed allowing the soil bed to be pre-stressed. This is achieved by injection of pressurized mortar (pressing). The paper analyzes the effect of soil pre-stressing followed by pressing of foundation with the cement mortar, as applied to existing structures using the Plaxis 3D software package in conditions of volume deformation and the Hardening Soil Model. Variable order of foundation pressing allows the required parameters of soil bed to be achieved in plan and depth, thus improving interaction with the foundation and superstructure.

The paper discusses deformation of over consolidated soils in Hardening Soil Model in terms of their initial stress state. When carrying out numerical analysis in Plaxis, it has been stated that Hardening Soil Model “remembers” the history of previous loadings. In forming the initial stress state of over consolidated soils with the pre-overburden pressure POP, there occurs the more reliable description of the soil deformation process than with the over consolidation ratio OCR. These findings are valid for odometer conditions and for real geotechnical calculations.

The paper describes a new method of drill-injection pile installation formed by the sleeve technology with solution injection using the “fracturing” mode and the controlled broadening at the pile end. This method is aimed at high-quality and effective compaction of the soil under the strip foundation of the reconstructed building. Analyzed are the results of the in-situ tests intended to interaction of drill-injection piles manufactured by the sleeve technology and single and repeated solution injections using the “fracturing” mode and the controlled broadening at the pile end. The radius of the neighboring compacted soil massif zone was determined. The geometric parameters of the pile shaft broadening, and fractures were identified. The algorithm for calculating the basic parameters of the proposed piles was developed in order to forecast their interaction with a silty-clayed soil foundation under static loading. A comparison with classical analytical solutions after soil mechanics, theory of elasticity and plasticity was made.