• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.5
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• pp.65-70
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• 2012

The current-carrying capacities in IEC standards for underground refers to a soil thermal resistivity of 2.5[$K{\cdot}m/W$] where no measured data are available. But this value is considered too conservative and may not justifiable economically as to need precaution in using the value. In this paper, the standard practices on the application of soil thermal resistivity of some countries(UK, USA etc) are surveyed and proposed a reasonable representative value 1.0[$K{\cdot}m/W$] of soil thermal resistivity considering the domestic soil thermal properties with regard to the application of IEC standard.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2380-2382
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• 1999

An Ampacity of a power cable depends on the soil thermal property, especially the soil thermal resistivity. Also, The soil thermal resistivity depends on the soil moisture contents in soil surrounding the power cable. This paper propose the prediction algorithm of the soil moisture contents using the Thornthwaite theory.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.174-176
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• 1993

Laying up homogeneous power cable in the earth. we sure that one of the most effectest fact is the rising of thermal resistivity. Today, system designing of in and outdoor project, calculating current carrying capacity totally depend on standard of JCS-168D and IEC-287 to applicate. Specially, the formula of calculating soil thermal resistivity is what is based on KENELLY,s is usually used. In this report, Let's study the formula of soil thermal resistivity which was born in the idea of KENELLY.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.22-24
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• 2002

This paper introduces the real-time soil thermal property analyzer and temperature measuring system which is combined with radio telecommunication technique. To measure the thermal parameters in real-time, the radio telecommunication technique are used the personal communication service (PCS) which is in the world-wide serviced commercially firstly by CDMA. The thermal property analyzer has an ability of measuring thermal resistivity, thermal diffusivity and thermal stability. To estimate the soil thermal properties, the curve fitting algorithm by means of the least square method are used. TCP/IP protocol and MTM are used to install the real-time soil thermal property and temperature measurement system at multiple locations along routes of the underground power cables and to reduce the cost of telecommunication.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.576-578
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• 2000

This paper address the prediction method of a soil thermal property depending on soil moisture contents and suggests the guideline to determine the soil thermal resistivity for the calculation of the cuurent carrying capacity of underground power cables in Korea.

• Journal of the Korean Geosynthetics Society
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• v.10 no.4
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• pp.113-121
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• 2011

River sand has generally used for the backfill material of underground power cables. The thermal resistivity of it has $150^{\circ}C$-cm/Watt in wet condition and more than double in dry condition. The final goal of this study is to find the backfill material which has a small change in thermal resistivity with various water contents, for example thermal resistivity is $50^{\circ}C$-cm/Watt and $100^{\circ}C$-cm/Watt in wet and dry conditions respectively. In this study it is presented that the comparison of thermal resistivity using stone powder, crush rock, weathered granite soil and Jumunjin sand as well as river sand in the needle method regarding water content, dry unit weight and particle size distribution. As a result, the thermal resistivity of a material is minimized when they have maximum dry unit weight at optimum moisture content and maximum density by appropriately mixing materials for particle size distribution. Therefore thermal resistivity characteristics should be considered two factors: one is the difference between natural dry condition and dry state after optimum moisture content, and the other is the difference between unit weight of raw material and maximum dry density.

• Journal of the Korean Geosynthetics Society
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• v.12 no.1
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• pp.83-92
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• 2013

Backfill material with thermal resistivity which has $50^{\circ}C$-cm/Watt in wet and $100^{\circ}C$-cm/Watt in dry is requested to improve the power transfer capability for dissipation of heat production in underground power cables. In the field test performed by buried cable backfills, the backfill material developed from this study is compared with river sand and weathered soil (native soil) to investigate the effect of heat transfer in various seasons and locations of thermal sensors. As a result, the developed backfill material is faster approaching yielding temperature (critical heat) than that of river sand and weathered soil, and it has good dissipation capacity rather than other materials by keeping moisture content at dry season.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1068-1075
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• 2006

Flow-able backfill is known as soil-cement slurry, void fill, and controlled low-strength material (CLSM). The benefits of CLSM include reduced equipment costs, faster construction, re-excavation in the future, and the ability to place material in confined spaces such as narrow parts nearly impossible for compaction or perimeter of underground power cables. A review of some recent full-scale tests carried out by KEPRI on slurry backfill materials for application in underground power cable was presented. Based on this research, applicability was assessed and compare to results of laboratory tests for improved slurry materials with optimal mixture contents.

• Journal of the Korean Society of Mineral and Energy Resources Engineers
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• v.55 no.6
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• pp.576-587
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• 2018

This study has focused on analysis factors affecting safety monitoring system at tailings sites, and the evaluation equipment to monitor the factors. Twenty sites at eighteen mines with unsafe conditions were selected to examine the equipment. There were three main factors influenced safety in the sites including surface erosion, piping, and slope instability. In detail, the surface erosion was divided into three sub-factors (planting, soil-topping layer, and tailings), piping into three sub-factors (liner, rain protection facility and leachate), and slop instability was also divided into three sub-factors (slop, concrete wall, and reinforcing wall). As results of in-field measurement, a CCTV was the most effective facility, and electrical resistivity survey, acoustic sensing, thermal liner sensor, structure inclinometer, rainfall meter, and flowmeter were also highly effective. According to applications of the facilities in the unstable tailings, structural defects were mainly found in the piping, which was the most important monitoring factor for safety management of tailings sites.