• Title/Summary/Keyword: Ground surface

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Ground Surface Potential Distribution near Ground Rod Associated with Soil Structures (대지구조에 따른 접지봉 주번의 대지표면전위분포)

  • Lee, Bok-Hee;Jung, Hyun-Uk;Baek, Young-Hwan
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.1
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    • pp.142-147
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    • 2007
  • This paper presents the distributions of ground surface potential rises as functions of soil structure and buried depth of ground rod. To propose fundamental data relevant to the reduction of electric shock of human beings due to ground surface rise, the ground surface potential rises near the ground rod were computed and measured. Ground surface potential rises near ground rod strongly depend on the soil structure, and an increase of the buried depth of ground rod results in a decrease of the ground surface potentials. The maximum ground surface potential appeared at the just above point of ground rod. Also, the measured results were in reasonably agreement with the data computered by grounding analysis program.

Ground Surface Temperature Distribution of Korea (우리나라 지표면 온도 분포)

  • Koo, Min-Ho;Song, Yoon-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.431-433
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    • 2006
  • Accurate information on the ground surface temperature is essential for design of a borehole heat exchanger and thus ensuring the performance of a ground source heat pump system along with knowledge on thermal diffusivity and conductivity of ground. In this study we analyzed the shallow subsurface temperature monitoring data of 58 Korea Meteorological Administration synoptic stations. As a result, we compiled mean annual ground surface temperature distribution map using multiple regression analysis of the monitoring data.

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A Trend of Back Ground Surface Settlement of Braced Wall Depending on the Joint Dips in Rocks under the Soil Strata (복합지반 굴착 시 암반층 절리경사 각도별 흙막이 벽체 배후 지표침하의 경향)

  • Bae, Sang-Su;Lee, Sang-Duk
    • Journal of the Korean Geotechnical Society
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    • v.32 no.11
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    • pp.83-96
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    • 2016
  • The surface settlement of the back ground of a braced wall due to the ground excavation has the great influence on the safety of the surrounding area. But it is not easy to predict the settlement of the surrounding area due to proud excavation. Estimation of the settlement of the surface ground induced by the deformation of the braced wall is performed by FEM and empirical method (Peck, Clough etc). In this research, surface settlement of the back ground braced wall depending on the joint dips in rocks during excavating the composit ground was measured at the large scale model test (standard: $0.3m{\times}0.3m{\times}0.5m$). The scale of model test was 1/14.5 and the ground was excavated in ten steps. Earth pressure on the braced wall and ground surface settlement on the back ground of a braced wall were investigated. The surface settlement during the excavation depended on the joint dips in rocks on of the ratio of rock layer. Maximum earth pressure and maximum surface settlement were masured at the same excavation step. In accordance with the increase of the rock layer dips and rock layer ratio, the ground surface settlement increased. The maximum ground surface settlement was 17 times larger at 60 degree joint dips in rocks than that of the horizontal ground conditions. And the position of the maximum surface settlement by empirical method was calculated at the point, which was 17%~33% of excavation depth. In accordance with the increase of the rock layer dips and rock layer ratio, the ground maximum surface settlement increased. The ground surface settlement of composite ground is smaller than that of the empirical.

Analysis of the Ground Surface Potential Rise using a Hemisphere-Shaped Test Model (반구형 실험모델을 이용한 대지표면 전위상승의 분석)

  • Yoo, Jae-Duk;Cho, Yong-Seung;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.12
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    • pp.208-213
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    • 2010
  • This paper deal with an analysis of the ground surface potential profiles using a hemispherical scaled-model. Because it is very difficult to draw valid conclusions concerning a general grounding problem from actual field data, scale model tests can be used to determine the ground surface potential profile around the grounding electrodes according to the configuration of grounding electrodes. In this work, a hemispherical vessel with a diameter of 1,100 [mm] was employed to simulate uniform soil and CDEGS program was employed to compare the measured and simulated results. As a result, the ground surface potential around the grounding electrode was significantly raised and the ground surface potential at the just upper point of ground electrode particularly was higher than other points. The ground surface potential of counterpoise was higher than other grounding electrodes such as mesh and grounding rods and the ground surface potential strongly depends on the frequency responses of grounding electrodes. Also the results measured with the small-sized model were in reasonably agreement with the data obtained from simulation.

Design of Walking Robot Based on Jansen Mechanism for Non-uniform Ground Surface (균일하지 않은 지면 보행을 위한 얀센 메커니즘 기반의 보행로봇 설계)

  • Jeong, YunWoo
    • Proceeding of EDISON Challenge
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    • 2016.03a
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    • pp.481-484
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    • 2016
  • Jansen mechanism is basic principal of walking robot. Because that mechanism have many link, walking robot can walk like animals. One of the feature is that space is existed between leg of walking robot and ground surface. So, it can walk through the non-uniform ground surface that have obstacle. In this paper, I will suggest design of walking robot that can walk on non-uniform ground surface effectively based on Jansen mechanism.

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Prediction of Industrial Noise Propagation Subjected to Ground Effect (지표면의 반사특성을 고려한 환경소음 예측)

  • 한상보
    • Journal of KSNVE
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    • v.11 no.2
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    • pp.329-335
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    • 2001
  • The analytical model of the ground wave can be used for the prediction of the noise level from a source above a plain and homogeneous ground surface with no obstacles nearby. Sound propagation along the surface of the ground can be affected by the roughness of the ground surface and the direction of the wind. The effects of the ground surface and the wind can be formulated in terms of the ground coefficient and the noise source parameter. Upward and downward conditions can also be addressed by considering the direction of the wind. The ground coefficient and the noise source parameter are estimated using the measured noise levels of two points under particular environmental condition, and the noise levels of arbitrary points under the same environmental condition can be estimated. The proposed method can be utilized to estimate the noise level of specific noise environment and its validity was confirmed with the results of actual field measurement.

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A Study on Fluoride Contents in Surface and Ground Waters in Korea. (지표수 및 지하수중 불소 함량에 관한 연구)

  • Kim, Sung-Ja;Noh, Pyung-Ui;Bak, Young-Soo
    • Journal of Environmental Health Sciences
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    • v.3 no.1
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    • pp.9-12
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    • 1976
  • A study was performed to find out the fluoride contents in surface and ground waters from June, 1973 to July, 1974. Water samples were collected from 53 surface and ground water sources. The results are as follows: 1. Out of 53 samples, the ground water of Hwaengsung had the highest fluoride contents (1.6 mg/l) and 13 samples did not. have fluoride at all. 2. The waters from Yoju (ground), Chongnung (ground) Hwaengsung (ground) and Namyang (ground) had optimum fluoride level (0.6~1.7mg/l) for the prevention of dental caries. 3. The ground waters had more fluoride contents than surface waters and the waters of coastal areas had less fluoride contents than those of inland. 4. The waters of Kangwon province had the most fluoride contents (mean 0.57mg/l) and the waters of Cheju do had the least fluoride contents (mean 0.06 mg/l)

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Analysis of seepage in trenching for surface desiccation of dredged soft ground (준설매립지반 표층건조처리를 위한 트렌치 굴착시 간극수의 침투해석)

  • 정하익;오인규;이용길;이승원;이영남
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.529-536
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    • 2002
  • The purpose of this paper os to present and discuss some of flow and drain observed in modelling results. Because dredged fill ground of Yul-Chon located in the south coast of Korea is very soft, this ground should be improved after operation of surface stabilization. There are surface stabilization method such as chemical stabilization, desiccation, horizontally vacuum drain, replacement, and geosynthetics. In Yul-Chon, PTM(Progressive Trenching Method) is adopted to provide the necessity condition of surface desiccation. In the case trench in the dredged soft ground is formed by PTM equipment, pore water in the ground is drained through trench. There, drain and desiccation of surface ground increase, and bearing capacity is improved. In this research, when trench in the dredged soft ground is formed by PTM equipment, permeable characteristics and drain efficiency of pore-water are analyzed using SEEP/W software package. Results show variation of total head, pressure head, flux, hydraulic gradient, and flow quantity.

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Comparison of the nutrient concentration between surface water and ground water in a rural watershed (농촌 소유역에서의 지표수와 지하수의 영양물질 농도 비교)

  • Song, Chul-Min;Kim, Jin-Soo;Oh, Kwang-Young;Gwon, Seong-Il;Jiang, Jie
    • Proceedings of the Korea Water Resources Association Conference
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    • 2007.05a
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    • pp.157-161
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    • 2007
  • Nutrients were investigated for surface water, bottom sediment and ground water in a rural watershed from January 2006 to March 2007. The concentrations of TN and $NO_3-N$ in ground water were higher than those in surface water due to fertilization on cabbage upland neighboring a river during March to August, but lower than those in surface water during September to February. However, the concentrations TP and $PO_4-P$ in ground water were lower than those in surface water. The concentrations of TP and $PO_4-P$ in surface water was lower than those in bottom sediment. The TP concentration in the bottom greatly decreased during rainy season. due to flush sediment of bottom, and then gradually increased.

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Comparison of the nutrient concentration in ground water between paddy field and upland in a rural watershed (농촌 소유역에서의 논과 밭의 지하수 영양물질 농도 비교)

  • Jang, Hoon;Kim, Jin-Soo;Kim, Young-Hyeon
    • Proceedings of the Korea Water Resources Association Conference
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    • 2009.05a
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    • pp.1994-1998
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    • 2009
  • Nutrients were investigated for surface water and ground water of paddy field and upland in a rural watershed from May 2008 to January 2009. The cocentrations of TN and $NO_3-N$ in ground water higher than those in surface water due to fertilization on cabbage upland neighboring a river during May to September, but lower than those in surface water during October to January. However, the concentrations TP and $PO_4-P$ in ground water were lower than those in surface water. TP and $PO_4-P$ concentrations in ground water of paddy field were generally lower than those of upland.

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