• Title/Summary/Keyword: Installation depth

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Reliability of Pile Driving Formula (항타공식의 신뢰도)

  • 박영호;김경석
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.03a
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    • pp.209-216
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    • 1999
  • Prefabricated piles used for construction of highway bridges are most of steel pipe piles and few of prestressed concrete piles. Its installation and inspection are less controllable and have much uncertainty due to changes in subsoil and groundwater conditions. However, most of these piles have been controlled using outdated pile driving formula such as Hiley's formula which models just the energy conservation due to its simple applicability in the field. This formula results in overstriking or sometimes understocking due to buckling of pile head. Engineers cannot ensure by the formula whether pile is installed properly. To compensate the drawbacks of excising pile formula, parameters in Hiley's formula and 55 formula are reviewed. Final sets used in pile formula and PDA test results(E.O.I.D) are measured during pile driving along the depth. These measured results along the depth were compared with each other and with N values, so that relations between the each result could be inferred. Also the factor of safety which can be used for pile driving formula are suggested.

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Study on the characteristic of heat exchange for vertical geothermal system using the numerical simulation (수치 시뮬레이션을 이용한 수직밀폐형 지열시스템의 채열특성에 관한 연구)

  • Nam, Yu-Jin;Oh, Jin-Hwan
    • Journal of the Korean Solar Energy Society
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    • v.34 no.2
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    • pp.66-72
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    • 2014
  • Ground source heat pump system can achieve high efficiency of performance by utilizing annually constant underground temperature to provide heat source for space heating and cooling. Generally, the depth of constant-temperature zone under the ground depends on surface heat flux and soil properties. The deeper the ground heat exchanger is installed, the higher the heat exchange rate can be acquired. However, in order to optimally design the system, it is necessary to consider both the installation cost and the system performance. In this study, performance analysis of ground source heat pump system according to the depth has been conducted through the case study.

Performance and Flow Characteristics of Axial Fan (축류팬의 성능 평가 및 주변 유동 특성)

  • 김재원;정윤영
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.11
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    • pp.972-981
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    • 2000
  • Comprehensive work is done for flows by an axial fan by experimental research. The present model fan is used for air handling device for out-door unit of an air conditioner in home appliance. PIV(Particle Image Velocimetry) system and wind tunnel are adopted for measurements of flows and performance evaluation, respectively. Major experimental conditions are the installation depth of a fan into a bellmouth of it. Optimal position of a fan in an inlet guide tube is observed by examination of fan-performance and flows in both upstream and downstream of the fan. Consequently, in the case of the fan inserted in half depth into the inlet tube, the efficiency of fan shows its maximum value and flow patterns is also streamlined.

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Wire and Wireless Transmitting-Receiving Set for Vertical Angle and Depth Measurement of Deep Mixing Method (유무선송수신을 이용한 심층혼합처리공법 수직도 및 심도 자동측정에 관한 연구)

  • Han, Woo-Sun;Yu, Chan;Han, Man-Bok
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.629-634
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    • 2002
  • Demands for the automatic measurement on angle and depth of equipment were arisen for the better construction in deep mixing method and grouting method. Civil, geotechnical, electronic, and communication experts worked together for the development of automatic measuring devices using wire and wireless transmitting-receiving set. The results on the development of automatic devices in an industrial installation will be presented.

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A Retrospection on Foundation Design of Taipei 101

  • Chin, Chung-Tien;Chao, Hsiao-Chou;Chang, Der-Wen
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.09a
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    • pp.145-156
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    • 2009
  • Large diameter bored pile was selected as the foundation type for Taipei 101. The pile construction method and specific construction procedures were determined based on the results of trial installation and pile load tests. The baseline for foundation design was established using the friction versus depth characteristics of each ground layer obtained from the pile load tests. As the ground profile and depth to the top of rock formation varied significantly on this site, the pile length, bearing capacity and settlement for single pile were analyzed using the information interpreted from adjacent boreholes. The post grouting at pile tip was mandatory for pile construction. Nevertheless, it was treated as a measure reducing the influence of construction uncertainties and providing extra safety for the foundation system.

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Design of convection current circulation system in reservoir using CFD simulation (CFD모사를 이용한 저수지 물순환장치 유동 설계)

  • Lee, Yosang
    • Journal of Environmental Impact Assessment
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    • v.21 no.1
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    • pp.133-142
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    • 2012
  • Convection Current Circulation System(CCCS) in stratified reservoir controls development of anaerobic condition and algal bloom during summer. In order to increase the CCCS effectiveness, we analyze diverse design parameters to make optimize the flow pattern in reservoir. In this study, we interpret the internal flow with installation and operation condition of CCCS based on CFD in reservoir. Design variables of CCCS is reservoir depth, stratification strength, distance of between CCCS and so on. Since reservoir depth and stratification strength in variables is depending on natural phenomenon, we evaluated current circulation effect by distance of CCCS and proposed the optimal design condition using CFD simulation. Flow and diffusion changes in water body was assessed by temperature and dye test. Changes in water floor temperature at 40m intervals was slowly descending over 37 hours. Dye diffusion simulation at 60m intervals, the radius of the spread between two devices were overlapped after 12 hours.

Distance measurement system compensated parameters for extraction of 3D distance (원거리 물체의 3차원거리 측정시의 파라미터 보정된 거리측정시스템)

  • Kim, Jeong-Man;Kim, Young-Min;Kim, Won-Sup;Hwang, Jong-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.605-606
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    • 2005
  • Depth error correction effect for maladjusted stereo cameras with calibrated pixel distance parameter is presented. Intra and extra parameters should be obtain to determine the relation between image and world coordination through experiment. One difficulty is in camera alignment for parallel installation: placing two CCD arrays in a plane. If the pixel distance parameter which is one of intra parameter is calibrated with known points, such error can be compensated in some amount. Such error compensation effect with the calibrated pixel distance parameter is demonstrated with various experimental results.

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Fiber optic distribution temperature sensing in a borehole heat exchanger system (광섬유 센서를 이용한 지중 열교환기 시스템 온도 모니터링)

  • Shim, Byoung-Ohan;Lee, Young-Min;Kim, Hyoung-Chan;Song, Yoon-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.451-454
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    • 2006
  • Fiber optic distributed temperature sensing and thermal line sensor are applied in an observation borehole and a loom deep borehole heat exchanger. For the case of permanently installed system fiber optic DTS is very useful. By comparing with TLS, fiber optic DTS shows good accuracy and reliability. Ground water flow can give influences at heat exchange rate of the heat pump system. According to the hydraulic characteristics and temperature-depth profile, we consider that temperature-depth profile do not seem to be dependent on ground water flow. A permanent installation of fiber optic cable is expected as a reliable temperature measurement technique in a borehole heat exchanger system.

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Theoretical resistance in cylindrical electrodes with conical tip

  • Hong, Chang-Ho;Kim, Jin-Seop;Chong, Song-Hun
    • Geomechanics and Engineering
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    • v.30 no.4
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    • pp.337-343
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    • 2022
  • The electrical resistivity method is a well-known geophysical method for observing underground conditions, (such as anomalies) and the properties of soil and rock (such as porosity, saturation, and pore fluid characteristics). The shape of electrodes used in an electrical resistivity survey depends on the purpose of the survey and installation conditions. Most electrodes for field applications are cylindrical for sufficient contact with the ground, while some are conically sharpened at their tips for convenient penetration. Previous study only derived theoretical equations for rod-shaped electrodes with spherical tips. In this study, the theoretical resistance for two cylindrical electrodes with conical tips is derived and verified experimentally. The influence of the penetration depth and tip on the measurement is also discussed.

Evaluation of Relative Corrosion Rate depending on Local Location and Installation of Structural Member in Steel Water Gate (강재 수문의 부재 위치 및 설치 방향에 따른 상대 부식속도 평가)

  • Ha, Min-Gyun;Jeong, Young Soo;Park, Seung hun;Ahn, Jin-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.7
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    • pp.16-24
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    • 2019
  • The corrosion amounts of steel structures can be different depending on their installation condition and height. Thus, their corrosion maintenance should be considered depending on installation conditions of local structural members. In this study, an atmospheric exposure test was conducted to evaluate the corrosion amount and the corrosion rate depending on the installation condition and height of a steel water gate using monitoring steel plates and corrosion environment measuring sensors. The mean corrosion depth was evaluated using the weight loss method and the galvanic corrosion current was measured by corrosion environment measuring sensors. Local corrosion rate of local structural member in steel water gate was estimated using measured mean corrosion depths and galvanic corrosion currents. From this measurement results, the corrosion damage in horizontal member of the cross beam was highly evaluated than those of other structural member as skin plate, etc. The relative difference in the corrosion rate of a local structural member could be highly affected by local corrosion environments of steel water gate members. Therefore, an appropriate maintenance method should be considered for local corrosion damages of local structural members determined by local corrosion environments of a steel water gate.