Evolutionary-based prediction of ε50 for the lateral load-displacement behavior of piles in clayBabak Ebrahimian
, Aida Nazari
, 2013, izvirni znanstveni članek
Opis: Analyzing piles that are subjected to lateral loads reveals that their behavior depends on the soil’s resistance at any point along the pile as a function of the pile’s deflection, known as the p-y curve. On the other hand, the deformation characteristics of soil defined as “the soil strain at 50% of maximum deviatoric stress (ε50)” have a considerable effect on the generated p-y curve. In this research, several models are proposed to predict ε50 specifically for designing the very long pile foundations of offshore oil and gas platforms in the South Pars field, Persian Gulf, Iran. Herein, ε50 is evaluated using extensive soil data, including in-situ and laboratory test results using evolutionary polynomial regression (EPR). The effects of the undrained shear strength, the normalized tip resistance of the cone penetration test, the over-burden pressure, the plasticity index and the over-consolidation ratio on ε50 are investigated in marine clays. It is demonstrated that the normalized cone tip resistance, which is an indication of the soil’s undrained shear strength, leads to more realistic ε50 values compared with the laboratory-derived undrained shear strength parameter. In addition, the application of the soil-index properties and the over-burden pressure in the models, improves their estimation quality. Furthermore, the results of full-scale lateral pile load tests at different sites are used in order to validate the performance of the proposed models when it comes to predicting the behavior of the lateral piles.
Ključne besede: p-y curve, laterally loaded pile, piezocone penetration test, PCPT, marine clay, evolutionary polynomial regression, EPR, South Pars field
Objavljeno: 14.06.2018; Ogledov: 393; Prenosov: 46
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The influence of electric arc activation on the speed of heating and the structure of metal in weldsOleksandr Savytsky
, Mychailo Savytsky
, Darko Bajić
, Yuriy Shkrabalyuk
, Tomaž Vuherer
, 2016, izvirni znanstveni članek
Opis: This paper presents the results of a research related to the impact of electric arc activation onto drive welding energy and metal weld heating speed. It is confirmed that ATIG and AMIG methods, depending on metal thickness, single pass weldability and chemical composition of activating flux, enable the reduction of welding energy by 2-6 times when compared to conventional welding methods. Additionally, these procedures create conditions to increase metal weld heating speed up to 1,500-5,500 °C/s-1. Steel which can be rapidly heated, allows for a hardened structure to form (with carbon content up to 0.4%), together with a released martensitic structure or a mixture of bainitic-martensitic structures. Results of the research of effectiveness of ATIG and AMIG welding showed that increase in the penetration capability of electric arc, which increases welding productivity, is the visible side of ATIG and AMIG welding capabilities.
Ključne besede: arc welding, active flux, penetration, heating speed, driving energy
Objavljeno: 07.07.2017; Ogledov: 493; Prenosov: 267
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Impact of soil composition on fall cone test results : technical noteBojana Dolinar
, Ludvik Trauner
, 2005, izvirni znanstveni članek
Opis: The cone penetrometer method is being increasingly used for the determination of the liquid limit of cohesive soils. The same method can be used to determine the plastic limit according to the known relationship between soil moisture content and depth of cone penetration. This relationship is non-linear, yet becomes linear on a log-log scale resulting in a simple methodof determination of liquid limit and plastic limit values. This technical note determines the soil properties that define these index parameters. Experimentally obtained results suggest that the index parameters primarily depend on the type, size, and quantity of the clay minerals in soil.Soil index parameters such as the liquid limit and plastic limit can be determined from knowledge of the mineralogical properties of the soil because this dependence appears well defined.
Ključne besede: soil mechanics, soil tests, clays, cohesive soils, soil properties, Attenberg limits, cone penetration tests
Objavljeno: 01.06.2012; Ogledov: 1550; Prenosov: 38
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