Browsing by Author "Shapoval, Volodymyr"
Now showing 1 - 3 of 3
Results Per Page
Sort Options
Item Determining the Influence of Physical Nonlinearity of Soil Strength Properties on the Estimated Base Resistance(Private company "Technology center", 2019) Shashenko, Oleksandr; Shapoval, Volodymyr; Kovrov, Oleksandr; Skobenko, Alexandr; Tiutkin, Oleksii L.; Babii, Kateryna; Samorodov, Oleksandr; Slobodyanyuk, SergeyENG: The paper has examined the potential of using nonlinear models of strength in determining the initial critical load on soil, as well as the standardized and estimated base resistance, which makes it possible to reduce labor intensity in the process of determining the strength properties of soils.Based on the analysis and generalization of results from theoretical studies into geomechanical processes using analytical mathematical methods, the formula modifications have been derived that are intended for determining the initial critical load on soil, as well as the standardized and estimated base resistances.We have established interrelation between strength, in particular specific cohesion, and the angle of internal friction, which are included in the strength conditions by Mohr-Coulomb and A. Shashenko, thereby making it possible to improve the procedure for calculating external loads on soil.The dependences of critical loads on base on the mean pressure under the sole of the foundation haven been analyzed in the range of pressure Р = 100...500 kPa using the strength conditions by Mohr-Coulomb and A. Shashenko.It has been established that when using generally accepted estimation formulae to determine the critical loads on base, it is required that the pressure range should be taken into consideration at which the properties of soil strength were determined. In this case, using the Shashenko failure criterion to determine critical loads on base makes it possible to properly consider the impact exerted by the mean pressure on them under the sole of the foundation.In contrast to dependences used currently in the Ukrainian, Belarusian, Russian regulatory documents, as well as in other countries’ standards, the resulting formulae make it possible to take into consideration the dependences of soil strength properties on the mean pressure on soil under the sole of the foundation. The results obtained make it possible to improve the reliability of determining the initial critical load on soil, as well as the standardized and estimated base resistances. This is achieved by taking into consideration the nonlinearity of the Mohr limiting circles’ envelope using the strength condition by A. Shashenko.Item Features of the Nonlinear Calculation of the Stress-Strain State of the "Rock Massif–Excavation Support" System Taking into Account Destruction(Kaunas University of Technology, Kaunas, Lithuania, 2019) Shashenko, Oleksandr; Shapoval, Volodymyr; Khalymendyk, Oleksii; Andrieiev, Volodymyr S.; Arbuzov, Maxim; Hubar, Oleksіy V.; Markul, Ruslan V.ENG: The algorithm for estimating the reliability of the results of the calculation of the stress-strain state of the “rock massif-excavation support” system, taking into account the non-linear relationship between stresses and strains, as well as the destruction of the rock, is presented. In the course of a numerical experiment, it was shown that to determine the reliability of the calculation results, it is enough to find the relative error between the maximum efforts in the lining and then the extremum (more precisely, the maximum) of the “relative error – depth of the excavation center”.Item Stability Assessment of the Slopes and Side-Hills with Account of the Excess Pressure in the Pore Liquid(Національний технічний університет «Дніпровська політехніка», Дніпро, 2020) Shapoval, Volodymyr; Shashenko, Oleksandr; Hapieiev, Serhii; Khalymendyk, Oleksii; Andrieiev, Volodymyr S.ENG: Purpose. The strength criteria substantiation of water-saturated soils and mine rocks, which make it possible to obtain the analytical solutions necessary for determining the stability of water-flooded soil slopes and side-hills. Methods. The methods are applied of analysis and generalization of the theoretical and numerical experimental studies results. The rocks and soils characteristics are taken into account: specific cohesion c, internal friction angle φ, compressive strength Rc and tensile strength Rp of the rock, as well as the bulk density. The load q was imposed to the water-saturated seam roof from the overlying mine rock or soil seams, the weight of equipment or structures located on the surface. It was accepted that the seam is saturated with water (gas) with the excess pressure Р. A point on the mine working surface (or vertical slope surface), located at a depth z is considered. It is determined at which ratio of q, P and z parameters the soil or rock seam will be destroyed. The problem solution is based on the Mohr-Coulomb strength criterion. Findings. The strengths of water-saturated rock and water-free rock are compared. The ratios have been obtained that make possible to determine the critical load on the daylight surface of water-saturated and water-free vertical slopes, side-hills, trenches and foundation pits, as well as various mine workings in soil bases and mine rocks. The analytical solution has been obtained, which makes it possible to determine a value of the critical pressure on the water-flooded vertical surfaces and soil slopes. The generalization has been made of a certain one-dimensional Mohr-Coulomb strength condition for a water-saturated base characterized by the strength characteristics с and φ for the dimensional case. Originality. It has been theoretically proved that for any pore pressure value in the water-saturated mine rock (or soil) their strength will be less than in their water-free state. New solutions have been formulated for determining the critical height of a water-saturated vertical soil slope or the wall in the vertical mine working. Practical implications. The obtained results make it possible to solve the practical engineering problems on determining the stability of water-saturated slopes and side-hills with a load-free daylight surface, therewith, taking into account the weight of the equipment, stored material and the stability of vertical walls of water-saturated seams of open-cut mine workings.