Showing 6 results for makarchian
Hojat Mehralizadeh, Masoud Makarchian,
Volume 14, Issue 28 (1-2019)
Abstract
Using spudcan as foundations for jack-up rigs is usual. Model dimensions, consolidation of clay, and spudcan penetration are the most important issues in modelling of this type of foundations in clays. Penetration of CPT cones and spudcan foundations in single- layered clayey soils was investigated in this paper. Cement stabilized clay with 5 and 10 percent cement was used to study the effect of undrained shear strength of clay on load- penetration behavior of spudcan; Also, two CPT cones with different diameters were used to estimate the undrained shear strength of clay layers. Results show that cement stabilized clays can be used for modelling of clay layers with different strengths. However, careful attention should be paid for changing of bearing capacity factors in two cases, with or without cement. Results show that cones with smaller diameters can be used in physical modelling with good accuracy as well as conventional ones.
Sajjad Gholipour, Masoud Makarchian,
Volume 15, Issue 29 (4-2019)
Abstract
Skirted foundations are an appropriate alternative to deep foundations in onshore and offshore structures, which have the ability to withstand uplift loads, are also easy to be installed. The tensile performance of skirted foundations on sand was studied by physical and numerical modeling. Laboratory tests were carried out on small-scale foundation models with peripheral skirts. Numerical modeling was performed by 3D finite element analysis for verifying the results of physical tests, as well as generalizing the results to the large-scale models. The effects of geometry and soil properties parameters including foundation diameter, sand shear strength, skirt depth, surface roughness, and load inclination angle were investigated. The results showed that the presence of peripheral skirt improves the behavior of tension bearing capacity of foundations on sand; Improvement values increase with increasing skirt depth, sand shear strength, roughness of foundation surfaces, and also, with decreasing the load inclination angle relative to vertical direction.
Sajjad Gholipour, Masoud Makarchian, Reza Gholipour,
Volume 16, Issue 32 (11-2020)
Abstract
The limitations of shallow foundations in terms of bearing capacity and settlement in soft clayey soils show the importance of the studying about so-called skirted foundations. The skirted foundations with penetrating into the soil and lateral confinement of soil can improve the bearing capacity and settlement behavior. These foundations are suitable for use in various applications such as seawater, beaches and dry lands. The objectives of this research are to evaluate the behavior of the skirted circular foundations on soft clay bed, and to estimate the improvement of bearing capacity and settlement reduction of skirted foundations using the numerical modeling. Various parameters including foundation diameter, skirt depth ratio, un-drained strength of clay, roughness of interface between foundation-soil and soil heterogeneity were investigated. The analysis results showed a significant improvement in skirted foundations performance in terms of bearing capacity enhancement and settlement reduction compared to the surface foundations. The improvement values increased with increasing the ratio of skirt depth, the roughness of the foundation surface and decreasing the shear resistance of the clay. The bearing capacity values of skirted foundations for the same depth and diameter were obtained close to the values of pier foundations.
Mohammad Shirdel, Masoud Makarchian,
Volume 16, Issue 32 (11-2020)
Abstract
The regional waterways, especially Persian Gulf and Oman Sea, are witnessing the passage of giant oil tankers daily. Due to oil extraction in the oil fields, wars in the region, unexpected incidents, and various explosions, southern areas of Iran are contaminated with oil derivatives. In this paper, the impact of crude oil and gas oil contamination on clayey fine soil and its impact on coastal structures is investigated. For this purpose, in addition to preliminary tests, hydrometer test, direct shear test, unconfined compressive strength and solidification were carried out on contaminated soils. It was found that the presence of more than 20% of petroleum derivatives on clayey soil leads to a sharp decrease in soil shear strength, which is considered as a serious risk for the coastal structures and oil field structures. Also, by using type II cement with 10% of dry soil weight, in addition to the relative increase in soil strength, it can also prevent the movement of contamination in water and soil substrates.
Masoud Makarchian, Sajjad Gholipour,
Volume 18, Issue 35 (5-2022)
Abstract
The behavior of circular surface foundations resting on sand, surrounded by peripheral skirt was studied by numerical analysis. The performance of skirted foundations was analyzed by evaluating the effect of different parameters and compared with the results of semi-deep and embedded foundations in the depths of skirt tip. The effect of lateral sand confinement on foundations behavior was evaluated by examining the parameters of foundation width, sand shear strength, skirt depth, and surface roughness. The results of numerical analysis were compared with small-scale physical modeling data. The results showed that the vertical bearing capacity of surface foundations due to lateral confinement, significantly increased and the settlement also decreased. The skirt existence causes resistance to soil lateral displacement and leads to a significant improvement in the response of the foundation. The improvement values increased with increasing skirt depth and decreasing sand shear strength. Depending on the different parameters, bearing capacity of skirted foundations increased by about 1.8 to 3.3 times, and settlement values reduced up to 54% those of surface foundations. Comparison of the results showed that the values of bearing capacity and settlement of skirted foundations are close to those of pier foundations with the same depth and width.
Ali Ipakloo, Masoud Makarchian,
Volume 20, Issue 42 (4-2024)
Abstract
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The soil of the civil projects often lacks the necessary geotechnical characteristics for the implementation of the project. Therefore, the importance of studies related to soil improvement methods is revealed. Some of the methods are soil stabilization with different polymers and reinforcement with fibers. This research examines the combined effect of stabilization and reinforcement of sandy soil with epoxy resin polymer and polyethylene fibers on standard density and unconfined compressive strength. In this regard, epoxy resin and polyethylene fibers are mixed with sand in different percentages and various tests have been performed on the samples. Also, to check the processing period, the samples were tested 4 times. The results of the tests indicate that adding epoxy resin to the samples up to 6% increased the strength, reduced the failure strain, and increased the stiffness of the specimens. Also, adding polyethylene fibers to the optimum percentage of additives to the specimens has increased the unconfined compressive strength, increased the failure strain, and decreased the stiffness of the specimens.
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