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Weak marine clay deposits exist all along the seacost of many parts of the world. Due to the poor engineering characteristics of these deposits, they pose several foundation problems to various coastal structures. Because of the high salt content in these deposits, the electro-osmotic technique has been effectively adopted to stabilize these deposits with some inorganic additives. In this investigation, the physico-chemical changes that occurred in a marine clay with various inorganic additives are presented and discussed. The improvement in the strength and plasticity characteristics of the soil have also been studied and reported. The newly formed reaction products arising out of the diffusion of lime are identified using X-ray diffraction technique (XRD). The present study indicates great promise regarding the use of electro-osmotic technique with inorganic additives as a quick remedial measure for the in-situ stabilization of coastal marine clay deposits. 相似文献
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The use of lime to improve the engineering properties of weak marine clays is a common method from the past. Recent studies indicate that the various foundation problems occurred with passage of time for offshore structures due to hostile wave conditions and adverse climatic conditions. Hence, there is an urgent need to improve the engineering properties of these soft deposits using well established ground improvement techniques. In the present investigation, an attempt has been made on two marine clays to investigate the microchanges that occurred at particulate level due to the addition of lime and sodium hydroxide chemicals. The influence of sodium hydroxide additive on the fabric of lime treated marine clays has also been studied using scanning electron microscopy (SEM) technique. The formation of various new reaction products due to soil-lime reactions and their stability in marine environment were also studied and reported using x-ray diffraction (XRD) technique. The test results indicate that lime stabilization is effective for improving the properties of marine clays and the presence of sea water increases the efficiency of lime stabilization. 相似文献
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E. Saranathan R. Chandrasekaran D. Soosai Manickaraj M. Kannan 《Journal of the Indian Society of Remote Sensing》2011,39(1):107-115
Coastal zone is very dynamic, being the meeting place of land and sea water. The development in coastal area and subsequent
population growth have given rise to problems such as erosion, sedimentation, saltwater intrusion, degradation of natural
resources, etc. Satellite data has proved to be more appropriate for change detections quantifying and monitoring coastal
zones compared to conventional sources. An attempt is being made to elucidate the effect of shoreline changes with reference
to the spatial and field data observed along the Tharangampadi area. The base map was prepared on 1:50,000 scale for delineation
and identification of shoreline changes. The spatial variability of shoreline changes are studied using IRS 1B LISS-II 1991,
IRS 1C LISS-III 2004 and IRS P6 LISS-IV and IRS 1D PAN merge data 2006. The corresponding Survey of India toposheets of 1852,
1972 and survey and land record village map of 1918 also supplemented for this study. The kind and extent of shoreline changes
were investigated by using GPS during ground truth verification. The results are analyzed and presented in this paper. The
study results revealed that 180 m receding of the shoreline occurred in the past 155 years. 相似文献
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Lime migration studies in marine clays 总被引：3，自引：0，他引：3
Weak marine clay deposits are present in several regions of the world and they are imposing severe problems for structures founded in these deposits. The use of lime to improve the properties of these soft deposits is not new. In the present investigation, a test programme was carried out to study the migration of lime into the marine clay from the installed lime columns and lime slurry injected points. The formation of various cementation compounds due to soil-lime reactions were identified by X-ray diffraction studies and the attributed changes occurring in the engineering properties of the soil systems were studied. The test results indicate that a sufficient amount of lime is diffused into the soil systems with time and the presence of excessive sodium ions in sea water does not retard the effective penetration of lime into the soil. It is suggested that both the lime-column and lime-injection techniques can be conveniently used to improve the behaviour of soft marine clayey deposits. For weak marine clays under large depths of water, the lime-injection technique is better suited. 相似文献
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Among compliant platforms, the tension leg platform (TLP) is a hybrid structure. With respect to the horizontal degrees of freedom, it is compliant and behaves like to a floating structure, whereas with respect to the vertical degrees of freedom, it is stiff and resembles a fixed structure and is not allowed to float freely. The greatest potential for reducing costs of a TLP in the short term is to go through previously applied design approaches, to simplify the design and reduce the conservatism that so far has been incorporated in the TLP design to accommodate for the unproven nature of this type of platform. Dynamic analysis of a triangular model TLP to regular waves is presented, considering the coupling between surge, sway, heave, roll, pitch and yaw degrees of freedom. The analysis considers various nonlinearities produced due to change in the tether tension and nonlinear hydrodynamic drag force. The wave forces on the elements of the pontoon structure are calculated using Airy's wave theory and Morison's equation, ignoring the diffraction effects. The nonlinear equation of motion is solved in the time domain using Newmark's beta integration scheme. Numerical studies are conducted to compare the coupled response of a triangular TLP with that of a square TLP and the effects of different parameters that influence the response are then investigated. 相似文献
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This study investigates the dynamic response of a Triangular Configuration Tension Leg Platform (TLP) under random sea wave loads. The random wave has been generated synthetically using the Monte-Carlo simulation with the Peirson–Moskowitz (P–M) spectrum. Diffraction effects and second-order wave forces have not been considered. The evaluation of hydrodynamic forces is carried out using the modified Morison equation with water particle kinematics evaluated using Airy's linear wave theory. Wave forces are taken to be acting in the surge degree-of-freedom. The effect of coupling of various structural degrees-of-freedom (surge, sway, heave, roll, pitch and yaw) on the dynamic response of the TLP under random wave loads is studied. Parametric studies for random waves with different Hs and Tz under the presence of current have also been carried out. For the orientation of the TLP, surge, heave and pitch degrees-of-freedom responses are influenced significantly. The surge power spectral density function (PSDF) indicates that the mean square response is affected by the amplification at the natural frequency of the surge degree-of-freedom and also at the peak frequency of the wave loading. The PSDF of the heave response shows higher peak values near the surge frequency and near the peak frequency of the wave loading. Surge response, therefore, influences heave response to the maximum. Variable submergence seems to be a major source of nonlinearity and significantly enhances the responses in surge, heave and pitch degrees-of-freedom. In the presence of current, the response behaviour of the TLP is altered significantly introducing a non-zero mean response in all degrees-of-freedom. 相似文献