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1.
The use of lime to improve the properties of soft clays is not new. Recently the deep lime mixing technique has been extended to coastal regions for improving the behavior of weak marine clays. But lime treatment technique should be approached carefully for clay containing a high percentage of sodium sulphate. The presence of sulphate in lime-treated clays may result in high swelling due to the formation of the expansive mineral, ettringite. A limited study of lime-treated marine clays has shown a need to further explore the formation of ettringite and its stability with time. In this article, a laboratory investigation was carried out to examine the influence of sodium and calcium sulphates on the behavior of lime column treated marine clay. Scanning electron microscopy (SEM) was used to identify the formation of various reaction products, including ettringite. Test results indicate that the formation of ettringite in the lime-sodium sulphate-clay system adversely affects the engineering behavior of the marine clay, whereas the addition of calcium sulphate significantly improves the engineering characteristics of the soil. 相似文献
2.
ABSTRACT The use of lime to improve the properties of soft clays is not new. Recently the deep lime mixing technique has been extended to coastal regions for improving the behavior of weak marine clays. But lime treatment technique should be approached carefully for clay containing a high percentage of sodium sulphate. The presence of sulphate in lime-treated clays may result in high swelling due to the formation of the expansive mineral, ettringite. A limited study of lime-treated marine clays has shown a need to further explore the formation of ettringite and its stability with time. In this article, a laboratory investigation was carried out to examine the influence of sodium and calcium sulphates on the behavior of lime column treated marine clay. Scanning electron microscopy (SEM) was used to identify the formation of various reaction products, including ettringite. Test results indicate that the formation of ettringite in the lime-sodium sulphate-clay system adversely affects the engineering behavior of the marine clay, whereas the addition of calcium sulphate significantly improves the engineering characteristics of the soil. 相似文献
3.
Compressibility behaviour of lime-treated marine clay 总被引：2，自引：0，他引：2
The necessity to tap natural marine resources from the ocean beds represents a considerable challenge for the construction of offshore structures on weak marine deposits. The use of lime to improve the behaviour of soft clays is not new. The present investigation examines lime-induced changes in the compressibility of marine clay. The test results indicate a reduction of 1/2 to 1/3 in the compressibility of the soil system within 30 to 45 days of treatment. The formation of various cementation compounds due to soil–lime reactions improves the soil characteristics with time. The results encourage the application of lime column and lime injection techniques to improve the engineering behaviour of soft marine clayey deposits. However, one has to be cautious in applying the lime technique to marine clays that contain sodium sulfate. 相似文献
4.
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
5.
Abstract Rapid industrial growth and increasing population has resulted in the discharge of wastes into the ocean, wastes which ultimately reach the seabed and contaminate the marine sediments. The soil-contaminants interaction, and their associated physico chemical properties with sediments control the behavior of marine clays. Marine clay deposits of low strength and high compressibility are located in many coastal and offshore areas. There are several foundation problems encountered in these weak marine clays. In this study, experimental work was carried out in the laboratory to stabilize soft marine clays using the lime column technique. Also the lime-induced effects on the physical and engineering behavior of marine clays in sulfate-contaminated marine environment was investigated. Consolidation tests indicate that compressibility of the lime-treated samples was reduced to 1/2–1/3 of the virgin soil after 45 days treatment. The test results also suggest that the lime column technique can be conveniently used to improve the behavior of contaminated marine clay deposits. 相似文献
6.
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 chemicals 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 influence of temperature on the engineering behaviour of chemical piles treated clays in the presence of sulphate and chloride contaminated marine environment. The formation of various cementation compounds due to soil-lime reactions were identified by X-ray diffraction studies, and the attributed changes occurred in the engineering properties of the soil systems were also brought out. The test results indicated that the increase in temperature has improved the engineering properties of soil significantly. 相似文献
7.
Rapid industrial growth and increasing population has resulted in the discharge of wastes into the ocean, wastes which ultimately reach the seabed and contaminate the marine sediments. The soil-contaminants interaction, and their associated physico chemical properties with sediments control the behavior of marine clays. Marine clay deposits of low strength and high compressibility are located in many coastal and offshore areas. There are several foundation problems encountered in these weak marine clays. In this study, experimental work was carried out in the laboratory to stabilize soft marine clays using the lime column technique. Also the lime-induced effects on the physical and engineering behavior of marine clays in sulfate-contaminated marine environment was investigated. Consolidation tests indicate that compressibility of the lime-treated samples was reduced to 1/2-1/3 of the virgin soil after 45 days treatment. The test results also suggest that the lime column technique can be conveniently used to improve the behavior of contaminated marine clay deposits. 相似文献
8.
Soft marine clay deposits pose several foundation problems and such weak clay deposits have been found both along seacoasts and in offshore areas spread over many parts of the world. We suggest using some chemical injection techniques to improve the engineering behaviour of soft underwater marine clays. A test programme was carried out by injecting lime into a soft marine clay in a test tank. The penetration of lime into the soil was established by taking a number of pH measurements and calcium oxide estimation from samples taken at various radial distances. The improvement in the plasticity characteristics of the soil has been verified by indices tests. Test results indicated the improvement in the strength and reduction in the compressibility of the soil with time. The beneficial changes that occurred in the soil have been attributed to the formation of cementation compounds and these compounds have been identified by using X-ray Diffraction Technique (XRD). The test results show good promise for the use of lime grouting in the treatment of weak marine clayey deposits. 相似文献
9.
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
10.
In this study, research was conducted to examine the performance of the lime pile application, a deep chemical stabilization method to improve the engineering characteristics of marine soil deposits. By using a laboratory-scale model, the marine soil sample was compacted into soil blocks in circular steel test tanks, with the installation of lime piles in them. An experimental program examined the effect of lime piles on physical and engineering properties of the soil in terms of curing periods and lime pile radial distances. Test results showed that clay fines, linear shrinkage, compressibility, and swelling pressure decreased, while permeability, preconsolidation pressure, and stiffness increased significantly with an increase in curing periods and within a close distance to the lime piles. Also, the electrical resistivity of the treated soils was examined to monitor the changes in their electrical properties. Finally, the correlation between the measured electrical resistivity and swell pressure values of the tested soils at different curing periods suggested that the electrical resistivity values can be used as a monitoring technique for deep chemical treatments of the subsurface soil. 相似文献
11.
Zhang Dingwen Fan Libin Liu Songyu Deng Yongfeng 《Marine Georesources & Geotechnology》2013,31(4):360-374
Soft clay with high sodium chloride salt concentration is a problem encountered by geotechnical and highway engineers. Chemical stabilization using cement is an attractive method to improve the engineering properties of soft soil. However, very limited studies have been conducted to reveal the effect of salt concentration on the engineering properties of cement-stabilized soil and the reported results in literature are not consistent. The impact of sodium chloride salt on the strength and stiffness properties of cement-stabilized Lianyungang marine clay is studied in this study. The clay with various sodium chloride salt concentrations was prepared artificially and stabilized by various contents of Ordinary Portland cement. A series of unconfined compressive strength (UCS) tests of cement stabilized clay specimen after 7, 14, and 28 days curing periods were carried out. The results indicate that a high sodium chloride salt concentration has a detrimental effect on the UCS and stiffness of cement-stabilized clay. The detrimental effect of salt concentration on the strength and stiffness of cement-stabilized clay directly relates to cement content. Soils mixed with high cement content are more resistant to the negative effect of salts than soils mixed with low cement content. The ratio of modulus of elasticity to UCS of cement treated soil does not have an obvious relationship with salt concentration. The findings of this study present a rational basis for the understanding of the impact of salt on the engineering properties of cement-treated soil. 相似文献
12.
The microstructure of lime-stabilized marine clay 总被引：2，自引：0，他引：2
The treatment of fine-grained soils with lime makes the soil system less sensitive to the changes in stress and other environmental factors. In the present investigation an attempt has been made to examine the nature of reaction products formed in a marine clay due to lime treatment using scanning electron microscopy (SEM) studies. The lime-induced microstructural changes in a marine clay have been investigated using SEM. The test results indicate that there is an overall improvement in the structure of the soil system resulting in a porous system due to the formation of new reaction products. 相似文献
13.
Large deposits of marine clays are encountered all along the Indian coastal belt. These clays are pleistocene to recent in origin, are considered to be young, and were deposited in a salt or brackish environment. These clays are very soft in consistency with low in-situ strength and high compressibility. The properties of these soil deposits depend mainly on the clay minerals present. In the present investigation, the mineralogical studies of some Cochin marine clays were carried out using XRD technique. The physical and chemical properties of these deposits were also reported. The test results were compared with some earlier reported works on marine clays. 相似文献
14.
S. G. Chung P. H. Giao T. S. Nagaraj J. M. Kwag 《Marine Georesources & Geotechnology》2013,31(4):237-254
Large scale reclamation works in coastal areas of the Nakdong River plain are at various stages of progress, since early 1990's on in-situ soft marine clay deposits. These deposits are of the order of 30 to 40 m thick. A realistic rapid characterization of soft ground would ensure success of any reclamation work in this area. In order to cope with the work carried out with different agencies, it is desirable to evolve a systematic methodology. In this study, engineering properties of clays at three coastal areas, Gadukdo, Noksan and Shinho, have been generated. The analysis of data has been done within the framework of classical developments in soil mechanics. Analysis has also been made by making use of the recent developments in dealing with soft clays. The dominant factors, namely, stress, time, and environment influencing the response of clay to loading are identified. 相似文献
15.
S. G. Chung P. H. Giao T. S. Nagaraj J. M. Kwag 《Marine Georesources & Geotechnology》2002,20(4):237-254
Large scale reclamation works in coastal areas of the Nakdong River plain are at various stages of progress, since early 1990's on in-situ soft marine clay deposits. These deposits are of the order of 30 to 40 m thick. A realistic rapid characterization of soft ground would ensure success of any reclamation work in this area. In order to cope with the work carried out with different agencies, it is desirable to evolve a systematic methodology. In this study, engineering properties of clays at three coastal areas, Gadukdo, Noksan and Shinho, have been generated. The analysis of data has been done within the framework of classical developments in soil mechanics. Analysis has also been made by making use of the recent developments in dealing with soft clays. The dominant factors, namely, stress, time, and environment influencing the response of clay to loading are identified. 相似文献
16.
AbstractThe coastal area of Fujian Province in China is rich in both sea sand and sea mud. However, sea sand and sea mud are both unsuitable as direct filler materials for seawalls due to their poor geotechnical properties. To turn waste into a useful product, a mixture composed of sea sand and sea mud is proposed as a filler material for seawalls. The strength, compressibility, moisture sensitivity, and permeability of the mixture are investigated experimentally. The results show that when the mass ratio of sea sand to limed sea mud is 1:2, the mixture exhibits good engineering properties and can serve as a filler material for general engineering purposes in dry environments. To apply the mixture under saturated conditions, both cement and lime are used to improve the engineering properties of the mixture. The improvements in the properties increase with both the binding agent content and the curing time, and the improvement with the addition of cement to the mixture is better than that with the addition of lime. The engineering requirements of seawalls can be satisfied by adding cement, and the cement content can be chosen according to considerations of the construction period and engineering costs. 相似文献
17.
Contaminant transport modeling in marine clays 总被引：1，自引：0，他引：1
G. Rajasekaran K. Murali S. Nagan V. Amoudhavally V. Santhaswaruban 《Ocean Engineering》2005,32(2):117-194
The need to develop various offshore containment systems encourages the contaminant transport study in marine clays. In the present investigation, an attempt has been made to examine six cases of contaminant transport in marine clays. Adequate literature background on the chemical diffusion of soils, and the earlier reported modeling techniques relevant to the present work have been highlighted. These methods enable a rapid examination of the impact of contaminant physical properties on the environment over a period of time. The numerical results of this study help to understand the chemicals transport phenomena in the marine environment especially at sea bed. 相似文献
18.
Permeability characteristics of lime treated marine clay 总被引：1，自引：0，他引：1
An attempt has been made to investigate the lime induced permeability changes in the permeability and engineering behavior of different lime column treated soil systems. Lime columns treated marine clay shows an increase in permeability up to a maximum value of 15–18 times that of untreated soil with time. The shear strength of the treated soil systems show an increment up to 8–10 that of untreated soil within a period of 30–45 days curing. In the case of lime injection systems, the permeability has been increased up to 10–15 times that of untreated soil, whereas the strength of the soil has been higher by 8–10 times that of untreated soil. Further, consolidation tests show a reduction in the compressibility up to 1/2–1/3 of original values. The test results revealed that both lime column and injection techniques could be used to improve the behaviour of underwater marine clay deposits. 相似文献
19.
AbstractIn the present scenario, with much focus on sustainable development worldwide, Microbially Induced Calcite Precipitation (MICP) is a promising biological soil improvement technology. However, only very limited research is reported on the effectiveness of this technique in marine clays. This paper presents the salient features of an experimental study conducted on two typical marine clays stabilised by MICP. Effectiveness of the technique was evaluated through a series of one-dimensional consolidation tests, unconfined compression tests, and index property determinations. It is found that biostimulation approach is not effective in marine clay; bio-augmentation is needed for soil improvement. Bio-augmentation results in the reduction of liquid limit and plasticity index to about 29% and 47%, respectively for the marine clays. A comparable improvement in volume change behaviour is also observed. There is a marked increase in undrained shear strength, upto about 148%, of MICP treated marine clays at toughness limit water content. Curing is also found to have a significant role in soil improvement. The observed transition in the nature of the tested marine clays from that of fat clay to elastic silt suggests the potential of the proposed approach. An empirical equation is also proposed to predict compression index of MICP treated marine clays. 相似文献
20.
数字海底的理论基础和技术实现--以渤海油田工程地质示范区系统为例 总被引：1，自引：0，他引：1
渤海油田资源的勘探开发促进了海洋工程建设的迅速发展。为避免海底不稳定性造成海洋工程巨大损夫或灾难性后果,在该区开展了大规模的海洋工程地质综合调查和评价研究。通过对数字海底技术的理论基础研究和在渤海油田工程地质示范区的具体实践,基于GIS理论、计算机硬件、软件以及网络技术,对渤海油田工程建设中的多源异构数据和图形进行标准化/整合、输入/输出、存储、查询和显示,研究开发的示范区系统可提供多种综合分析及应用服务,为海洋工程建设和油田工程安全保障提供了共享基础科学数据,对于防止海洋地质灾害、降低工程建设造价和保障工程安全运行具有重大的应用价值。 相似文献