• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.455-462
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• 2002

There exist several kinds of continuous consolidation tests to analyze the consolidation behavior of soft clay. The constant rate of strain (CRS) test has been adopted as a standard method by several countries, and some researches also have been peformed by domestic researchers. Among those, the constant pressure ratio (CPR) test is peformed with the constant ratio of excess porewater pressure to vertical effective stress. The test has the advantage of considerable reduction of duration time. In the study, the consolidation characteristics are analyzed by performing the CPR test as validate the pressure ratio with undisturbed soft clay and remolded clay, Also, results of the standard consolidation test and CRS test are compared to verify the CPR test can be employed for practical use. As a result, effects of variation of the pressure ratio on consolidation parameter are similar to the strain rate in the CRS test. Therefore, the test can be used to analyze the consolidation behavior of soft clay But the test have some problems such as expensive cost of equipment and highly skilled workmanship.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.271-276
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• 2002

Continuous loading is applied the sample has been developed to overcome some of the problems associated with the incremental loading consolidation test. Therefore, it is able to reduce the test time and provide a well defined the curve of effective stress versus strain due to continuous stress-strain points. Also, the constant rate of strain consolidation(CRSC) test has been accepted widely as a standard method in foreign countries because of its many advantages. However, in Korea the CRSC test has not been used in engineering practice and experimentally verified. Because there is not a precise criterion of testing despite consolidation characteristics are influenced on strain rate and Pore pressure ratio. Consequently, it is difficult to apply in engineering practice. In this study, artificial neural networks are applied to the estimation of th proper strain rate and pore pressure ratio of the CRSC test. This study shows the possibility of utilizing the artificial neural networks model of estimation of the strain rate and pore pressure ratio in the CRSC test.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.10a
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• pp.59-66
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• 1999

ILT proposed by Tezaghi was frequently used which is based on one dimensional consolidation theory. But this test require time longer than a week and has problems for extra soft clay such as the squeezing around the consolidation ring. Also consolidation curve is not clearly defined since only a few data is obtained in a test. Therefore it is difficult to determine Pc and the interpretation to determine the consolidation constants are rather complicated. In this paper, the stress-strain relationship and consolidation constant obtained by CRS and CG-test were analyzed and compared with the results by ILT.

• Proceedings of the KSR Conference
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• 2003.05a
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• pp.393-399
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• 2003

This paper describes a proper criterion for the constant rate of loading consolidation (CRLC) test which is a kind of the continuous loading consolidation(CRLS) and widely used as alternative methods to the incremental loading consolidation(ILC)test. With those results, the preconsolidation pressure estimated by the CRLC test turned out to be comparatively larger than that of the ILC test and it is increased in proportion to the applied loading rates. However, the compression index in the CRLC test is less ifluenced on by the loading rates. The coeffcient of consolidation and permeability in the CRLC test are dependent on excess pore pressure ratio mainly. In other words, if the pore pressure ratios are too low, the coefficient of consolidation and permeability become smaller than those of the ILC test. On the other hand, if the excess pore pressure ratios are too high, the coefficient of consolidation and permeability become so larger than those of the ILC test. Therefore loading rates should be carefully determined to generate proper excess pore pressure ratio.

• Journal of the Korean Geotechnical Society
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• v.25 no.4
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• pp.31-38
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• 2009

A continuous, fast, and convenient experimental method, replacing recent tests such as standard oedometer or self weight consolidation test, is needed for the determination of the consolidation behavior of unformed soft soils. This study introduced the seepage induced fast consolidation test using the flow pump technique. It can obtain the consolidation characteristics of unformed soft soils conveniently and fast. The seepage induced consolidation test apparatus consists of a modified triaxial cell, differential pressure transducer, flow pump, and displacement transducer. The test continuously proceeds with starting seepage forces induced consolidation, loading consolidation, and permeability test on the same sample. In addition, this test result was compared with the standard oedometer test result to make this method valid. From this study it was found that this method is a convenient and time saving effective method for obtaining data required for calculation of consolidation settlement of unformed soft soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1070-1077
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• 2005

The purpose of this study is to establish a proper criterion for the constant rate of loading consolidation(CRLC) test which is a kind of the continuous loading consolidation(CLC) and widely used as alternative methods to the incremental loading consolidation(ILC)test. With those results, the preconsolidation pressure estimated by the CRLC test turned out to be comparatively larger than that of the ILC test, and it is increased in proportion to the applied loading rates. However, the compression index in the CRLC test is less influenced on by the loading rates. The coefficient of consolidation and permeability in the CRLC test are dependent on excess pore pressure ratio mainly. In other words, if the pore pressure ratios are too low, the coefficient of consolidation and permeability become smaller than those of the ILC test. On the other hand, if the excess pore pressure ratios are too high, the coefficient of consolidation and permeability become so larger than those of the ILC test. Therefore, loading rates should be carefully determined to generate proper excess pore pressure ratio inside the soil specimen. From this study, good results are obtained from the CRLC test if the excess pore pressure ratios were in the range of 2.5 to 6.0 %, performed with loading rates between 0.0015 and 0.005 $kgf/cm^2/min$.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.361-368
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• 2000

In other to examine the compressibility characteristics of cohesive soils in the mouth of the Nakdong river, the oedometer tests were peformed on undisturbed and reconstituted samples obtained by continuous boring typically at 3 different sites. It is meaningful to compare the consolidation behavior of natural clays with a reference state because the natural clays are depending on the stress history, sedimentary environment and geological history. In this study, the insitu state of the Pusan clays was investigated using the concepts of ISL(Nagaraj, 2000) and ICL and SCL(Burland, 1990). And for the purpose of confirming the existence of the underconsolidated clays, a standpipe type piezometer test and a dissipation test by piezocone were performed at their sites. Consequently, the Pusan clays were evaluated as normally consolidated clays.

• Journal of Conservation Science
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• v.29 no.3
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• pp.249-259
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• 2013

This study was experimented on accelerated weathering test using salt and freeze-thaw to prove effects of consolidants and consolidation for stone cultural heritage. The samples used four kinds of stones (Gyeongju Namsan Granite, Iksan Granite, Yeongyang Sandstone and Jeongseon Marble) which to distributed by three type of weathering grade (Fresh, Weathered Stone and Highly Weathered Stone) added for thermal treatment. The samples were treated with three consolidants (Wacker OH 100, Remmers KSE 300 and 1T1G), and tested by 500 cycles with freezing-thawing and 50 cycles of salt weathering test. As a results of freezing-thawing test, the crack and destruction occurred from some samples. And total immersed samples maintained effect of consolidation to 200 cycles. Also, The rock particle was fall off and gradually destructed by salts weathering test. The consolidated sample relatively had fewer changes by the weathering than not treated sample. The sprayed sample had not continuous effect on weathering.

• Journal of the Korean GEO-environmental Society
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• v.2 no.1
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• pp.91-101
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• 2001

This paper investigates the effectiveness of quick lime piles for soft ground improvement. The field tests based on the results of the laboratory test were performed, and the results of field tests were compared with those of numerical analyses(FEM). The results of the field test showed that the domestic quick lime was very effective in reducing the water contents of the surrounding ground quickly due to its characteristics such as digestion, absorption, and exothermic reactions. Accordingly, consolidation occurred without any additional load increment and the shear strength of surrounding ground was increased more than twice. Therefore the quick lime pile method could be considered as an excellent improvement technique reducing the improvement period for soft ground. For the practical applications of the quick lime pile method, issues such as hydration heat, particulation and equipment enhancement should be solved through continuous research and development.

• Geotechnical Engineering
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• v.10 no.4
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• pp.153-166
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• 1994

In this paper, the experimental study on the behavior of the dredged clay was performed by introducing the consolidation teat method using continuous loading. Also a new testing method was examined and the strength of the dredged clay using thin plate was evaluated. The rheological characteristics of the dredged clay are described by the gingham model. The static and rheologic thin plate penetration test is proposed for the shear strength testing method. It is found that both of testing methods are reasonable and have a practicability. Especially, the strength increases for a water content which is less than two times of liquid limit in case of silty soil and clayey soil. About plasticity index, the strength increases rapidly for a value less than 10 for silt, 5 for clay which a water content is normalized by plasticity index of silty soil rather than clayey soil.