• Geomechanics and Engineering
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• v.9 no.1
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• pp.1-14
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• 2015

Piezovibrocones have been developed to evaluate the liquefaction potential of onshore soils, but have not yet been utilized to evaluate the in-situ liquefaction behavior of offshore marine and volcanoclastic sediments. Two static and vibratory CPTu (Cone Penetration Tests) were performed at Tauranga Harbor, New Zealand. The lithology is known from nearby drillholes and the influence of vibration on different types of marine soils is evaluated using the reduction ratio (RR) calculated from static and vibratory CPTu. A sediment layer with high potential for liquefaction and one with a slight reaction to cyclic loading are identified. In addition to the reduction ratio, the liquefaction potential of sediment is analyzed using classic correlations for static CPTu data, but no liquefaction potential was determined. This points to an underestimation of liquefaction potential with the classic static CPTu correlations in marine soil. Results show that piezovibrocone tests are a sensitive tool for liquefaction analysis in offshore marine and volcanoclastic soil.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.46-51
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• 2004

The surface layer in dredged and reclaimed marine clay is improved by mixing of shallow soils and hardening agents, which is made of cement, containing some other special admixtures. Tests in both laboratory and field settings are performed to investigate the improvement effect and strength properties of cement-stabilized soils. The test results show that the hardening agent sufficiently improves the soil properties of the surface layer, while increasing the load-carrying capacity. The strength of cement-stabilized soils depends, primarily, on water-to-cement ratio and curing temperature. That is, the higher curing temperature and the longer curing time, the higher the strength in cement-stabilized soils. The high ratio of water-ta-cement results in a lower strength.

• Journal of the Korean GEO-environmental Society
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• v.16 no.9
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• pp.5-12
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• 2015

A large amount of dredged soils occur in the marine purification project but dredged fine-grained soils have been abandoned as a waste. The standards as filling materials, banking materials, revetment blocks and concrete blocks were surveyed. Through the geotechnical tests of marine dredged fine-grained soils and the alkali-activation reaction, the usability as banking materials, revetment blocks and concrete blocks were analyzed. Dredged sands could be used as banking materials, and dredged fine-grained soils could be used as filling materials. A mixture of dredged fine-grained soils and dredged sands could be used as banking materials. Materials produced by the alkali-activation reaction could be used as a revetment block and a concrete block.

• Geomechanics and Engineering
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• v.14 no.6
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• pp.553-562
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• 2018

Road construction is becoming increasingly important in marine and desert areas due to population growth and economic development. However, the load carrying capacity of pavement is of gear concern to design and geotechnical engineers because of the poor engineering properties of the soils in these areas. Therefore, stabilization of the soils is regarded as an important issue. Besides, due to the fuels combustion and carbonate decomposition, cement industry generates around 5% of global $CO_2$ emission. Thus, using bentonite as a natural pozzolan in soil stabilization is more eco-friendly than using cement. The aim of this research is to experimentally study of the stabilized marine and desert sands using deep mixing method by ordinary Portland cement and sodium bentonite. Different partial percentages of cement along with different weight percentages of sodium bentonite were added to the sands. Unconfined compression test (UCS), Energy Dispersive X-ray (EDX), and Scanning Electron Microscope (SEM) were conducted on the specimens. Moreover, a mathematical model was developed for predicting the strength of the treated soils.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.677-684
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• 2000

Piezocone test as well as Dilatometer tests are used worldwide to evaluate the engineering properties of clay soils. The common strong point of the two tests is that they can estimate, by the identical test equipment, various properties of soils, which are the unit weight of soils of OCR, K$\sub$o/, undrained shear strength(s$\sub$u/), coefficient of consolidation(c$\sub$h/) and soil classification etc,. A series of the two types of field tests are performed in this study on marine clays with low plasticity at Inchon International Airport construction site to estimate various properties of the soils such as s$\sub$u/, OCR, and c$\sub$h/, which are then compared each other as well as with the results of reference tests. The comparisons show that the way of interpretation is the most critical factor in obtaining confidential results for a certain engineering property for both tests.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.3
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• pp.179-186
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• 2014

Weathering indexes of the typical pedons derived from different parent materials of the soils of Korea were calculated by Kronberg and Nesbitt (1981) to understand weathering degree of the soils which might give a clue of soil formation and characterizing a soil pedon. The weathering index W1 was chemical change index, and the weathering index W2 was silicate dominant index. The chemical compositions of the 49 typic pedons were extracted from the Taxonomical Classification of Korean Soils (NIAST, 1999). The weathering indexes of Kimhae series, derived from fluvio marine material, were the highest among the analyzed soils. Within parent materials, the weathering indexes of the soils derived from limestones parent materials were high, and those derived from phorphyry materials were low. The relationship between W1 and W2 showed unique pattern which implied certain sequence within the same parent materials.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1998.11a
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• pp.48-51
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• 1998

This paper presents the transport and removal of organic substances from the contaminated soft soils and sludges such as marine dredging waste, marine sediments, mine tailing waste, and sewage sludge by electroosmosis. A series of laboratory experiments including variable conditions such as contamination levels, solid contents, and applied voltage rates were peformed with the contaminated soft clay specimen mixed with organic substance. Investigated are specimen density, dewatering rate, outflow rate, and outflow concentration. The test results showed that organic substances in the soils were removed by applied voltages. The results indicated that this process can be used efficiently to clean up the contaminated soil.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.251-261
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• 2004

A series of column test with a silty marine soil mixed with Jumunjin Standard Sand were performed to investigate the characteristics of settling and consolidation of non-plastic dredged soils. Column tests were carried out by using the separable column to measure the grain size distribution of consolidated layer. Column tests were performed with changing the mixing ratio of Jumunjin Standard Sand to the silty marine soil, initial water content of slurry and initial height of slurry. Height of interface of slurry was monitored during tests and grain size distribution tests were carried out after finishing tests. Influencing factors on the particle segregation, eventually to the characteristics of settling and consolidation of non-plastic soil, were analyzed on the thesis of test results. As results of column tests, the mixing ratio of sand to the silty marine soil and the initial water content of slurry were known to affect the characteristics of settling and consolidation resulted in significant particle segregation of slurry. Initial height of slurry was found not to affect seriously to particle segregation.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.03b
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• pp.663-668
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• 2000

In this study, the Atterberg limit and grain-size analysis were carried for the purpose of investigating the influence on drying and organic matter of Ulsan marine deposited clay. The results revealed that Atterberg limit was decreased and grain-size distribution was variable on drying. The presence of organic matter also influenced on the physical properties of the soils. The physical properties of marine deposited clay were variable on drying, so that we recommended grain-size analysis and Atterberg limit test were performed under the wet condition of the soils after sampling.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.99-105
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• 1976

After investigation of soil characteristics the properties of a reclaimed marine soil (Gupo series) distributed along the southern coastal areas of Korea are summarized as follows: 1. Gupo soils distributed in the southern Ria coastal area are derived from rolling to hilly materials and are poorly sorted with less influences of river fluvial action. These soils have high content of sand compared with the broad fluvio-marine soils in the western coastal areas. 2. The morphological features of the poorly drained Gupo soils are greyish brown sandy loam with a few yellowish mottles in the surface horizon and are grey sandy loam with a few gravel in the sub-strata. The ground water table remains around 10-30cm below the surface. These soils, recently reclaimed younger deposits, do not show any evidence of illuviation. 3. The "n" value (about 0.8) of the Gupo soils indicates physically unripened soils. 4. pH value of these soils shows more than 8.0 throughout the profile. Organic matter contents are extremely low (around 0.5%) except 1.2 percent in the surface horizon. C.E.C. ranges from 7 to 9m.e/100g which is lower than average in the country. The ratios of extractable cations such as Ca, Mg, Na and K of the surface horizon are 20:7:4:1. Base saturation is more than 60%. Available phosphate content is very low that is less than 25 ppm. Electric conductivity of the soils at $25^{\circ}C$ ranges 7 to 12 mmhos/cm and increased with depth. 5. According to classification of soil based on physical ripening, the Gupo soils can be classified into "Unripe soils with half-ripe sub-soils". The soils could be classified into "Hydric Haplaquents" in the original of the 7th Approximation (1960), but into "Typic Haplaqents in the supplement of 7th approximation which the physical ripening condition is not clearly expressed. Soil Taxonomy, apparently the final version of the 7th approximation, defines the soils as "Haplic Hydraquents" that clearly show the condition of physical ripening as well as other properties. Other several classification systems applied do not describe physical ripening condition of the soils.