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Geotechnical Engineering Institute, Korea Institute of Civil Engineering and Building Technology, 1190 Simindae-Ro, Ilsanseo-Gu, Goyang-Si, Gyeonggi-Do, 10223, KoreaReceived 24 November 2015; received in revised form 21 December 2015; accepted 23 December 2015본 연구에서는 유류로 오염된 모래의 지반공학적 특성에 대하여 분석하였다. 오염물로 사용한 유류는 점도특성을 고려하여 등유, 원유, 자동차 엔진오일을 선정하였고, 모형지반은 주문진 표준사를 사용하였다. 실내시험은 다짐시험, 투수시험, 직접전단시험을 유류의 오염비율에 따라 수행하였다. 투수시험에서 유류의 함유비가 증가할수록 오염되지 않은 지반에 비해 투수계수가 점진적으로 저하되었다. 내부마찰각은 오염되지 않은 지반보다 상대적으로 감소하였다. 주요어 : 유류오염 , 점도, 다짐시험 , 투수시험 , 내부마찰각Contamination of soil due to an oil spill influences its subsequent behavior. An investigation was conducted tostudy the effect of oil viscosity on compaction characteristics, coefficient of permeability, and shear strength. Waterpermeability was also determined by using Kerosene, Engine oil, and Crude-oil as contaminants. The test resultsindicate that the compaction characteristics are influenced by oil contamination. Direct shear test was conducted toinvestigate the effect of oil in the pore space in sandy ground. angle of internal friction of sand (based on totalstress condition) decreases due to presence of oil within the pore spaces in sand. Key words: oil contamination, viscosity, compaction, permeability, internal friction

This work investigated the geotechnical characteristics of an embankment constructed with a mixture of soil and waste lime. The waste lime was a by-product of the manufacture of Na2CO3 at a near by chemical factory in Incheon. Field measurements were take three years after construction, and included geotechnical tests such as field density measurement, plate loading testing, dynamic cone penetration testing, and field CBR measurement. The results indicate that the geotechnical characteristics of waste lime mixtures are suitable for embankment works.

Global warming may induce an increase of active layer thickness in the Arctic region. The freezing and thawing of the active layer can damage infrastructures such as roads, railways, and embedded pipe lines in cold regions. A few methods, however, have been proposed to characterize the active layer. The objective of this study is to evaluate the characteristics of the active layer by laboratory and field tests, especially using the instrumented dynamic cone penetrometer (IDCP). Geographical and geological characteristics of Ny-Alesund, Svalbard are introduced, and the geotechnical properties, microstructure observations, and thermal properties of the Ny-Alesund soils are investigated. In addition, subsurface temperatures monitored for a year are discussed. The IDCP, which is able to measure the energies transferred into the rod head and the cone tip, is applied to the evaluation of the strength variation and the thickness of the active layer in Ny-Alesund. During dynamic penetration tests, the IDCP can produce profiles of the corrected cone tip resistance as well as the dynamic cone penetration index (DCPI). The results show that the active layer thickness estimated from the DCPI and corrected cone tip resistance profiles is approximately 1700 mm. Furthermore, the bottom of the active layer significantly corresponds to that estimated by the maximum ground temperature profile with a soil thermal diffusivity of 5.5 · 10− 7 m2·s− 1. This study represents the characteristics of Ny-Alesund soils investigated with a variety of laboratory tests, and suggests that the IDCP may be effectively used for active layer characterization.

The Antarctic continent exposed to strong wind, very low temperature, and extremely dry condition. The freezing-thawing cycles under this extreme environment change the mechanical characteristics of rocks near the ground surface. To investigate the effect of freezing-thawing cycles under the extreme environment understand on geotechnical properties of rocks, rocks from the Antarctica were collected from two places: (1) West Antarctic Cape Burks and (2) East Antarctic Terra Nova Bay areas. The rock characteristics of these two areas were described and compared. For Terra Nova Bay area, rock characteristics of rocks near the surface and depths exceeding 2.9 m were examined. The `near-the-surface rocks` averages of absorption rate, P-wave velocity, and unconfined compressive strength were 0.56%, 3,717 m/s, and 109MPa, respectively; while, those values of `deep-sited rocks` were 0.24%, 4,670 m/s, and 88MPa. From the measurements, it was found that the effects of weathering were not significant on mechanical characteristics (strength) but were pronounced on physical characteristics(absorption and P-wave velocity).

This paper addresses the potential use of granulated rubber as backfill material for buried pipelines in cold regions. An experiment on a laboratory scale buried pipe was conducted to evaluate the pipe-backfill interaction upon freezing. Two backfill materials were employed. In Case 1, sand was used as backfill material. In Case 2, granulated rubber was mixed with sand. Induced circumferential and longitudinal strains along the pipe were measured with movement of the freezing front into the backfill and an estimate of the freezing soil pressure was obtained based on the measured pipe strain. Experimental results showed that the behavior of the buried pipe was influenced by the progression of the freezing front and type of backfill material. Cold temperatures advanced faster into the sand backfill compared to the rubber-sand backfill due to the good thermal characteristics of rubber. Circumferential strains increased in both backfills indicating the development of freezing soil pressure in the backfill. Dominant vertical compressive strains were observed at 0° and 180° in both backfills. A significant reduction in strain and pressure exerted on the pipe upon freezing in the rubber-sand backfill was confirmed and the application of rubber mixed with sand as backfill material is possible.

The moisture condition of the active layer in Arctic regions can induce severe problems, such as ground subsidence and frost heave. Thus, the water content in the active layer needs to be estimated using a light and portable in-situ testing device. In this study, a penetration-type time domain reflectometry (PTDR) device is developed for the estimation of volumetric water content in the active layer. The developed PTDR is applied at a site for an electrical resistivity survey to characterize the water distribution along a measurement line. A PTDR consists of a PTDR module, connecting rods, and a guide with a hammer. The PTDR module can determine the dielectric constant of a material from the measurement of the travel time of electromagnetic waves. Using remolded soil samples, the dielectric constants measured from the PTDR are calibrated with the volumetric water content. The PTDR calibration demonstrates that the dielectric constant increases with the water content. For the temperature of 0.1 to 15.2 &deg, C, the travel time only slightly depends on the temperature variance. For field application, a PTDR is pressed into the ground and measures the electromagnetic waves and temperature with depth. The results of the field tests show that the volumetric water content measured by the PTDR increases with depth due to the impermeable layer located underneath the active layer. The electrical resistivity survey conducted at the same site provides the electrical resistivity profile for a long distance and shallow depth soils. Furthermore, the electrical resistivity survey and PTDR establish a significant correlation between electrical resistivity and water content. The PTDR developed in this study can be effectively used as an advanced in-situ testing method to estimate the water distribution in the active layer.

The electrical resistivity of soil is affected by various factors, such as the electrical resistivity of pore fluids, the porosity, the constituent of soil particles, the saturation, the orientation and shape of soil particles, and the pore structure. The purpose of this study is to determine the changes in the electrical resistivity of sand-silt mixtures during freeze-thaw cycles. To measure the electrical resistance over freeze-thaw cycles, a nylon cell was designed and an electrode was attached to each of the four side walls of the cell. Two specimens, with different degrees of saturation (40% and 60%), were prepared using sand-silt mixtures. The measured electrical resistances were then transformed into electrical resistivities. The results show that, in both specimens, the electrical resistance increases during the repeated cycles, and hysteresis behavior appears immediately after the beginning of thawing. In addition, the electrical resistivities of both samples are less during thawing than during freezing from 0°C to -3°C. While the electrical resistivity increases rapidly at 0°C during freezing, the electrical resistivity at 0°C decreases relatively gradually during thawing. For the specimens with a saturation of 40%, the electrical resistivity during thawing was greater than the electrical resistivity during freezing at ordinary temperatures. This study demonstrates that electrical resistivity surveys may be useful for analyzing the structure and behavior of soils during freezing-thawing cycles.

Temperature monitoring along the depth in construction site of the Jangbogo Antarctic research station (74° 37′S, 164° 12′E) was carried out. The thermal behavior of the frozen ground was investigated. The temperatures were measured during site investigation from February 07, 2011 to February 12, 2011. The temperature profile was analyzed in the frozen ground. The results show that the increase along with the depth. This study demonstrates that the temperature profile obtained at this site could be effective reference for the construction of the research station in the Antarctic.Copyright © 2012 by ASME

The second scientific Antarctica station of South Korea is under construction at Terra Nova Bay located in east Antarctica. The objective of this study is the evaluation of the frost heave susceptibility of soils sampled from the second station site by performing laboratory frost heaving tests. Experiments are carried out with the soil specimens taken from five different areas at Terra Nova Bay. Test specimens are frozen with constant temperatures at the top and bottom of the specimen at −17 °C and 4 °C, respectively. In addition, grain size analyses and unfrozen water tests are also performed for monitoring the characteristics of the water contained in the permafrost. Frost susceptibility is evaluated by standard methods recommended in UK, US and Japan. Experimental results show that the more the fine contents exist in soils, the more frost heave occurs. The result denotes that grain size has a significant effect on frost heave. The results suggest that the frost heaving susceptibility of the frozen ground at the Antarctic site would be effectively evaluated through the grain size and the frost heaving parameters.