• Proceedings of the Korean Geotechical Society Conference
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• 2001.03a
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• pp.453-458
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• 2001

Copper slag is produced about 700,000 tons annually though copper refining process in Korea. In the paper, a laboratory investigation was carried out to estimate the geotechnical properties of copper slag and examine the feasibility of using the copper slag as a substitute for conventional construction materials and the improvement of the soft clay deposit. The specific gravity of copper slag is 3.45, and pH is 7.83. And the size distribution of the copper slag is well graded, so usage of copper slag will be extended in Geotechnical engineering fields. Copper slag has the permeability of 3.502${\times}$10￣$^2$cm/sec, which is satisfied with the criterion of sand drainage materials.. At the same time, it is thought to be suitable material for sand mat since it meets JIS of grain size distribution. The content of CaO from steel slag is about 40 percent while that of CaO from copper slag is about 5 percent. Based on this fact, copper slag has less hardening property compared to steel slag. Therefore, copper slag can be used as vertical drains, filters, and sand mats for improving the soft deposit.

• Journal of Korean Society of Disaster and Security
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• v.10 no.1
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• pp.35-42
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• 2017

This is a comparative study on the characteristics of excavated soils, which is proceeded using soil strength parameter by literature, geotechnical investigation, standard penetration test by drilling, and downhole test by borehole at six sites in urban areas. The results of these site surveys are used as basic data for the evaluation and development of prediction of ground subsidence risk. Geotechnical properties are estimated with the result of standard penetration test-N value and literature. The dynamic geotechnical characteristics are also estimated with top-down seismic exploration at borehole.

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.67-74
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• 2004

A case study was performed to verify the applicability of existing formulae for predicting bridge scour in cases where its piers are founded in fine-grained soils. The object of study was the Kanghwa Choji Bridge area where the streambed consists of mainly clayey soil. Site investigation included: direct measurement of scour depths around piers using an ultrasonic probe; and collection of undisturbed soil samples which were later used to determine geotechnical properties and scour rate under different stream velocities. Scour depth prediction was made by employing several conventional methods and compared with the measured value. All methods, not taking soil's intrinsic property against erosion into consideration, overestimated scour depth by a factor of 3.6 to 6.5. On the other hand, the SRICOS method yielded a reasonably acceptable overestimation by a factor of 1.7.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.10a
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• pp.1340-1352
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• 2008

In this study, S-wave velocity range is gauged in every field test method at the total 5 locations in the marine deposits in Incheon area. field test method is accomplished the SPT(Standard Penetration Test), CPT(Cone Penetration Test), SPS(Suspension PS Logger), SCPT (Seismic Cone Penetration Test) and so on. The S-wave velocity of SCPT in the downhole test method is measured lower than SPS logger at the N value > 15 range. But at the N value < 15 range, SPS logger and SCPT result is measured same. In this result, although the soil strength of the downhole test method increased, the rate of S-wave velocity is tend to be slowed. This result shows that the downhole test is difficult to apply at the place that the intensity of soil is more extreme and harder soil. And it shows that the existing Imai(1982) type that is mostly used within the country is not suitable for the marine deposits. Thus, the empirical formula that can show the range of S-wave velocity in each N value for domestic soil is needed.

• Journal of the Korean Geosynthetics Society
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• v.3 no.4
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• pp.29-40
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• 2004

The factors affecting the long-term design strength of geogrids can be classified into factors on creep deformation, installation damage, temperature, chemical degradation, biological degradation. Especially, creep deformation and installation damage are considered as main factors to determine the long-term design strength of geogrids. This paper describes the results of a series of experimental investigation, which were conducted to assess the installation damage according to different fill materials and creep characteristic of various geogrids. The results of this study show that the installation damage and creep deformation of geogrids significantly depends on a row material and a manufacturing process of geogrids.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.577-585
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• 2015

Contamination of soil due to an oil spill influences its subsequent behavior. An investigation was conducted to study the effect of oil viscosity on compaction characteristics, coefficient of permeability, and shear strength. Water permeability was also determined by using Kerosene, Engine oil, and Crude-oil as contaminants. The test results indicate that the compaction characteristics are influenced by oil contamination. Direct shear test was conducted to investigate the effect of oil in the pore space in sandy ground. angle of internal friction of sand (based on total stress condition) decreases due to presence of oil within the pore spaces in sand.

• Geomechanics and Engineering
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• v.11 no.6
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• pp.771-785
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• 2016

The thermal conductivity of soils is an important property in energy-related geotechnical structures, such as underground heat pumps and underground electric power cable tunnels. This study explores the effects of geotechnical engineering properties on the thermal conductivity of soils. The thermal conductivities of quartz sands and Korean weathered silty sands were documented via a series of laboratory experiments, and its variations with effective stress, porosity, and water saturation were examined. While thermal conductivity was found to increase with an increase in the effective stress and water saturation and with a decrease in porosity, replacing air by water in pores the most predominantly enhanced the thermal conductivity by almost one order of magnitude. In addition, we have suggested an improved model for thermal conductivity prediction, based on water saturation, dry thermal conductivity, saturated thermal conductivity, and a fitting parameter that represents the curvature of the thermal conductivity-water saturation relation.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.365-368
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• 2003

Despite of the simple equipment and operation, DMT has been widely used to obtain various soil parameters and those parameters have been successfully applied to geotechnical design practice. Among them, the estimation of horizontal coefficient of consolidation is so useful that many researchs recently have been carried out. However, simulation of the penetration of the DMT blade is complex due to the inherent difficulty on analyzing a plane strain deformation of the soil around blade. Therefore, empirical and semi-empirical methods that use the theoretical solution developed fur piezocone with some assumptions have been used to estimate the coefficient of consolidation from Dilatometer dissipation test. In this paper, coefficients of consolidation c$\_$h/ which were obtained using equivalent radius that is same area with the DMT blade and optimization technique are compared with those obtained from Oedometer test and other interpretation methods. It was found that a new method used in this study can give more precise horizontal coefficient of consolidation than other methods do.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.03a
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• pp.697-700
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• 2003

The SASW method is a promising and effective way of profiling ground stiffness nondestructively. This method has been successfully applied to many geotechnical sites, but significant lateral variability, embedded obstacles, and pavement lead to the low reliability. To improve these problems, the horizontal wave component has been introduced to improve the reliability of the stiffness profile determined by the SASW method. To understand dispersion character of the horizontal component wave propagation in artificial profiles, FEM analysis had been performed. Used models are homogeneous half-space and two layered half- spaced layers.

• Proceedings of the Korean Geotechical Society Conference
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• 1991.10a
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• pp.75-86
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• 1991

In this paper the failure of Carsington Dam was discussed based on the informations reported in the first edition of Korean Geotechnical Society News. The causes of dam failure and its influences were evaluated based on the results of the slope stability analysis. The effects of the shear strain pre-existing in the yellow clay disclosed by the post-failure site investigation and the progressive nature of the dam failure were preponderantly evaluated. Stability analysis was performed based on the proposed values of strength parameters characterizing possible field ground conditions at failure. The calculated safety factors were evaluated for different cases of strength parameters in order to find the most probable field ground condition at the dam failue.