Influence of soil salinization level on compressive strain resisting

Погіршення екологічного стану оточуючого середовища та погіршення здоров’я населення, що проживає на територіях розробки калійних родовищ Прикарпаття, визначає необхідність вивчення екологічних небезпек та ризиків. Неефективна консервація рудників призвела до утворення провалів ґрунту, руйнування житлових будинків та промислових споруд. Проблема убезпечення від руйнування споруд цивільного та промислового будівництва є однією з найважливіших на даний час. Вивчення закордонного досвіду дозволяє здійснювати прогноз стійкості фундаментів будівель, споруджених на засолених територіях. Наявність у ґрунтах різних за кількісним складом солей впливає на деформаційні показники ґрунтів. При зволоженні засолених ґрунтів відбувається розчинення і винесення солей, які в них містяться, і відповідно до цього збільшується пористість ґрунту. За результатами розрахунків отримано залежності концентрації солей в рідині й питомого об’єму солей по товщині ґрунту з плином часу для випадків дисперсного та плівкового засолення. Побудовано кінетичні криві суфозійного просідання для дисперсного та плівкового типів засолення, використання яких дасть змогу прогнозувати й контролювати просідання засолених ґрунтів техногенно навантажених територій.The deterioration of the ecological state of the environment and health of the population living in developing Carpathians deposits of potassium, determines the need to study environmental hazards and risks. The problem of exploration and construction a significant land area is of importance in the conditions of modern society development. Great competition, high density of buildings and insufficient volume of land fund resulted in the use of structurally unstable soils under construction. In the industrial area of Kalush, Ivano-Frankivsk region, large area is occupied by saline soils, which belong to the district of development of Kalush-Holynska potassium salts deposits. The ineffective conservation of mines led to the formation of ground dips and destruction of civil and industrial buildings. The problem of insurance of civil and industrial buildings destruction currently is one of the major. While designing buildings, which are located in the area of the mine workings harmful impact, the State building standards of Ukraine and international standards must be taken into account. Study of foreign experience enables prediction of stability of buildings foundations constructed on saline areas. The presence of different quantitative composition of salts in soils affects the deformation parameters of soils. When saline soils are moistening the dissolution and removal of salts which they contain occurs, and accordingly the soil porosity increases. According to the results of calculations dependences between the concentration of salts in the liquid have been received and the specific amount of salt on the thickness of the soil with time in cases of disperse and pellicle salinity. Kinetic curves of suffosion subsidence to disperse and pellicle types salinity were built, the use of which will allow to predict and control subsidence of technologically loaded areas saline soils

Mathematical modelling of in-tube corrosion under gas hydrate

У процесі транспортування газу промисловими та морськими трубопроводами можливе утворення газових гідратів. Сформовані гідрати можуть закупорювати трубопроводи, підводні лінії транспортування, а у випадку газового викиду під час буріння гідрати можуть утворюватися в стояку свердловини в противикидному превентері й на штуцерній лінії. Розроблено емпіричну модель швидкості корозії, де газовий гідрат розглянуто в якості кородуючого агенту. В моделі розглянуто трубопроводи з вуглецевої сталі, по яких транспортується природний газ під різними значеннями температури pH, фугітивності та дотичного напруження стінок. Модель базується на принципах турбулентного потоку, закритої системи та умовах однорідної (гомогенної) фази. При створенні цієї моделі особливу увагу приділено термодинамічним властивостям складу газу. Ця модель є прогнозуючою за своєю сутністю, оскільки з її допомогою можна спрогнозувати залишковий ресурс трубопроводу. Оцінено вплив тиску, температури та дотичних напружень у стінці труби на швидкість корозійних процесів і показано, що при найнесприятливіших умовах швидкість корозії під дією газогідратів може досягати 174 мм/рік (0,48 мм/день), що спричиняє додаткові експлуатаційні ризики.Hydrate formation along a long natural gas pipeline has been established as a potential initiator of different types of internal corrosion along the pipe-length based on the formation stage and point. An empirical model on natural gas corrosion rate with gas hydrate as the corroding agent has been developed. The model considered carbon steel pipelines (with iron as alloyed metal) conveying natural gas at different temperatures, pHs, fugacities and wall shear stresses and is based on turbulent flow (Re › 2300), closed system and homogenous phase conditions.The model adequately predicted the pipe‘s shelf-life due to corrosion initiated through hydrate formed within a pipeline transporting natural gas at deepwater location and its effectiveness is confirmed by the ability of its plotted trends which agree with the available literature. The resulting corrosion rates from this model are increased with temperature, pressure and wall shear stress. This is in agreement with the available mathematical and experimental reports, which testify the reliability of this predictive model. The resulting corrosion rate from hydrates could be as high as 174mm/yr (0,48mm/day). This is extremely dangereouse level with that compared with the industry‘s standard to operate below 2mm/yr. At this rate, a pipeline would be subjected to full bore rupture within some days if corrective actions are not quickly taken. This extreme increase in corrosion rate will negatively impact operation by reducing the pipe-shelf life as well as the pipe‘s integrity. Also, increase in operating pressure increases the hydrate formation temperature. This increase in temperature will have secondary effects because of its influence on the solubility of the corroding agent(s). Since CO2 as the corroding agent for this study is very soluble in the formation water, any change in temperature will have result in other factors influencing the corrosion rate. Since the parameters needed for the model depend on various operating conditions and often change with distance within the pipe-length, the model could be thought of as being a point corrosion rate model. Nonetheless, since the model makes use of some physical data such as temperature and pressure, other parameters such as concentration, composition e.t.c. could be assumed to be constant over a few kilometers to reduce the iteration of measurement. This assumption could be costly

Modeling the influence of soil surfaces on their during the continious static loading

Закономірності зміни властивостей засолених ґрунтів підтопленні територій дуже важливі для проектування основ і фундаментів промислових і цивільних споруд. Проведено математичне моделювання зміни несучої здатності засолених грунтів.Patterns of change in the properties of soil salinity flooding areas are very important for designing bases and foundations of industrial and civil buildings. The mathematical modeling of the change in bearing capacity of saline soils was carried out

Assessment of Potential Environmental Risks from Saline Soils Subsidence

The nature and causes of soil subsidence in the areas of liquidated mining and chemical companies of the Carpathians are analyzed. Based on calculation results, was obtained dependences of salts concentration in the liquid, and the specific content of salt through the thickness of soil over time in cases of the dispersed and film salinity

The study of fatigue failure performance of vehicle metal structures used in transportation of corrosive materials

P. Popovych. The study of fatigue failure performance of vehicle metal structures used in transportation of corrosive materials //P. Popovych, L. Poberezhna, O. Tson, O. Shevchuk, O. Lyashuk/ Acta Mechanica Slovaca Faculty of Mechanical Engineering Technical University of Košice. Vol. 21, № 1. P. 48-52. ISSN 1335-2393Saturated solutions of the most aggressive working environments used in agricultural production, in particular ammonium sulphate and nitrophosphate are investigated to reduce fatigue resistance of ordinary steels groups – St3 and St5 (GOST 2651:2005; DIN 17100) and quality steels – 10 Steel, 15 Steel, 20 Steel, 25 Steel (GOST 1050-88; DIN 17200) when loaded at all levels. The fatigue endurance limit decreases in comparison with air up to 2.02 times in a solution of ammonium sulphate, and to 2.32 times in a solution of nitrophosphate

Fracture cause analysis of the extruder’s shaft and geometry optimization of the spline

The article is devoted to increasing of the durability of technological equipment elements, forecasting of the resource and diagnostics of failures of the technical system. The basic regularities are analyzed and causes of the failure of the extruder’s working body shaft are determined. For torque values M = 40.74 - 64.37 N·m and of the extruder’s working body shaft, the stress-strain state of the contact surfaces of the keyhole of the extruder’s shaft is calculated by the method of three-dimensional finite element modelling. The maximum values of the stress intensity σint(max), which arise on the edge of the key groove, are calculated. It was established that an increase in the distance of the key groove to the fillet of the working body shaft by 2.0 mm leads to a decrease in the maximum stresses on the edge of the key groove by 15.72%. The results of the research allow optimizing the geometry of the shaft

Influence of loads in the process of laying on the resource of sea pipelines

Purpose: In the process of laying on the bottom of the sea material of the pipeline undergoes single-cycle alternating load. The purpose of the work is to determine the effect of pre-operational loads on the resource of marine pipelines. Design/methodology/approach: The influence of the method of construction of pipelines on their stress-strain state is analysed. According to the real modes of packing of sea pipelines, the loading regime is programmed and the laboratory modelling of the pipelaying process by the S-method has been programmed. Findings: According to the results of one-cycle shift load were obtained characteristics of the hysteresis loop. It is proposed to simplify the mathematical description of the hysteresis loop of the pipeline laying cycle in the given form. It was shown that the preload during the construction process negatively affects the durability of the pipeline material due to the exhaustion of its plasticity resource, reducing it to 70%. Research limitations/implications: In the future, investigations into the effect of overloading and overloading during the repair of pipeline sections on their durability and on the safe exploitation of resources should be continued. Practical implications: The developed method of estimation of influence of preoperational loads in the process of pipeline laying on its safe exploitation resource is used in gas-extraction enterprises. Originality/value: To forecast the deformation behaviour of the pipeline material in the laying cycle, it is efficient to use diagrams of a sign-changing single-cycle bend, which were built considering the creep. The fatigue life capability of a steel pipeline depends on the history of the pipeline load in the laying cycle. Ratio σ*0.2c / σ* 0.2t and εyc / ε yt can use as power and deformation criteria for evaluating Bauschinger effect. It is suggested that fatigue damage is determined by the width of the hysteresis loop

Performance of bearing steel structures of vehicle used in transportation of aggressive agricultural materials

In bearing structures of automobile dump truck semi-trailers engaged in the transport of agricultural goods, mineral fertilizers, a large part of metal structures is under the direct influence of aggressive environments in combination with dynamic loads that arise when driving on roads. The peculiarities of corrosion processes when contacting steel surfaces of dump semi-trailers with mineral fertilizers, as well as their aqueous solutions, are insufficiently studied. Also studied mechanisms of electrochemical corrosion of materials of metal structures of agricultural vehicles to ensure their performance in conditions of prolonged aggressive environments. The authors determined that the mineral fertilizer medium is the most aggressive material used in cargo transportation in the agrarian sector mineral fertilizer and ammonium sulphate cause intense corrosion damage of typical materials of metal structures of automobile dump-carriers, which adversely affects reliability. The obtained results allow a better understanding of the causes of agricultural machines corrosion and can be used in assessing their residual resource