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In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

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The purpose of this work is resolving the problem of evaluating the structural strength of the steel screw single-bladed pile under the pressure of axial loads in various soil conditions. Calculations in this area constitute the necessary condition for assessing the possibility and feasibility of using pile-screw technology in specific construction conditions, inter alia, at main pipeline facilities. The dependence of the pressure curve on the blade on the soil stiffness modulus was revealed in the course of numerical simulation performed by the finite element method in the ANSYS software. The maximum pressures are observed at the junction of the blade and the pile shaft with a large soil stiffness modulus, if the soil stiffness modulus is small, then the maximum pressures are observed at the edge of the blade. An analytical method for assessing the strength of a single-blade screw pile is proposed based on the theory of bending of circular and annular plates, as well as the results of numerical modeling. Comparison of the analytical method for calculating the strength of a screw pile with the results of numerical modeling to assess the accuracy. The comparison results showed an accuracy sufficient for engineering calculation methods. Цель настоящей работы – решение задачи оценки прочности конструкции стальной винтовой однолопастной сваи при воздействии осевых нагрузок в различных грунтовых условиях. Расчеты в этой области – необходимое условие для оценки возможности и целесообразности применения свайно-винтовой технологии в конкретных условиях строительства, в том числе на объектах магистральных трубопроводов. По результатам численного моделирования, выполненного методом конечных элементов в ПК ANSYS, выявлена зависимость изменения эпюры давления на лопасть винтовой сваи от модуля деформации грунта: с увеличением значения модуля деформации грунта максимальные давления наблюдаются в узле сопряжения лопасти и ствола сваи, при малых значениях модуля деформации максимальные давления отмечаются у края лопасти. На основании теории изгиба круглых и кольцевых пластин, а также результатов численного моделирования предложен расчетный метод оценки несущей способности однолопастной винтовой сваи по материалу. Для оценки точности разработанного подхода к расчету прочности винтовой сваи проведено сравнение предложенного аналитического метода с результатами численного моделирования, которое показало достаточную для инженерных методов расчета точность. Общий принцип, заложенный в рассмотренном методе расчета, может быть использован для создания различных эпюр давления на лопасть в зависимости от модуля деформации грунта и характеристик винтовой сваи.