Effect of Nanoparticles on Contaminated Cohesive Soil for geotechnical structures

Zomorodian S.M. Ali, Shabnam Moghispor and Armina Soleymani

Generally, cohesive and contaminated soils are not suitable for geotechnical structures. Incidence of oil contamination in soils is inevitable during the process of production and distribution of oil and gas operations. One of the soil improvement techniques is adding an additive to soil. Given the widespread use of nanoparticles in various fields, using these materials in order to improve geotechnical properties of these soils can be a new approach. In this experimental study, the effect of adding nanoparticles and curing period on strength characteristic of kerosene contaminated soil and non contaminated cohesive soil was investigated. Hence unconfined compressive strength test was carried out on these two types of soil samples with different proportions of nanoparticles and different curing times. The unconfined compressive strength increases significantly by adding low percent of nanoparticles. For example the strength of contaminated sample was increased by 297% that contained 2% nanoclay with 28 days curing time. Also, the unconfined compressive strength of clean soil sample with the mix optimal percentage of nanosilica and nanoclay (1.5% and 1%) and 28 days curing time increased about 127%.

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Influence of crane and stack loads on berthing structure deck slab

Naidu G.T., Balaji K.V.G.D., Pavan Kumar M. and Murali K.

The demand for oil, gas and general cargo has grown significantly over the past 40 years. This growth is expected to continue so larger volumes of oil, gases and bulk cargo are to be transported in the near future; an important part thereof by shipping over the high seas. By using larger vessels, among other things, the transportation costs can be reduced. Many new ports will be constructed in more environmentally challenging conditions, so the loads working on the marine constructions and berthed vessels will be higher. Berthing structure is a general term used to describe a marine structure for the mooring of vessels, loading/unloading cargo and embarking and disembarking passengers. Damage to port/harbor structure was primarily due to Stack and Crane load. The sub-structure consisting of piles and diaphragm wall supported Deck slab berthing structure on marine soils are subjected to different loading conditions i.e. Mooring, BGML, Crane load, Stack load, Concentrated load and IRC 70R loadings. The literature on the adequacy of the STAAD. Pro modeling of berthing structure to analyze their behavior under varying the Stack and Crane loads is limited. This paper describes the influence of Stack and Crane loads on the bending moment induced in the Deck slab of berthing structure.

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A short review on analysis, behaviour and construction of encased stone columns

Muthukumar M. and Uma Shankar M.

Stone column technique is considered to be more effective technique in improving the shear strength of soft clays and loose granular deposits. This technique is also ideally suited for the loose granular deposits to mitigate liquefaction during earthquakes. Stone columns derive its load carrying capacity from the lateral confinement offered by the surrounding soil and thus increase the load carrying capacity and reduce settlement. To improve the performance of stone columns in very soft clays and very loose silts, stone columns are encased to provide additional confinement. Geosynthetics has been used successfully for encasing the stone columns. This encasement provides additional restraint because of the hoop stress induced on the encasement. This encasement also brings several benefits to the stone columns like increase in stiffness of stone columns, prevents intermixing of stone columns and soil, improving drainage characteristics etc. This paper critically reviews the current research progress and synthesizes the available information on the construction, analysis and behaviour of encased stone columns.

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