• Journal of the Korean Geophysical Society
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• v.1 no.1
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• pp.59-68
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• 1998

Ground penetrating radar (GPR) experiments were performed in a sand tank to study the ability of detection of buried pipes and to characterize the signal of the reflection wave. The ratios of diameter of buried pipes to the depth were set 4 up to 24 % and materials were metal, synthetic resin, and wood. In case of groundwater table below buried materials, strong reflection signals were observed irrespective of diameter and depth except for wood. While it is very difficult to detect the reflection signals in case that the groundwater table is set to higher than buried materials. The reflection signals from the bottom of the sand tank, however, were clearly observed even in case of higher groundwater table. This implies that the weak reflection signals from the buried materials are not all due to the wave attenuation. The vertical reflection profiling method is recommended in case that the object of the survey is to find horizontal position of buried material because this method has the advantage in cost and time of survey. However, the full or partial CMP gather method is recommended in case that the objects of the survey are to get the detailed subsurface information, i.e. the depth to buried material, interval velocity of geological layer, and mapping the groundwater table.

• International Journal of Highway Engineering
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• v.5 no.3 s.17
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• pp.31-42
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• 2003

The KHC Test Road project was initiated on 1991 to develop Korean Pavement Design Guide. It was constructed along the Joongbu Inland Expressway line between Yeoju and Gamgok. It is two-lane wide expressway containing fifteen asphalt and twenty-five Portland cement concrete test pavement sections. Various sensors were installed in the Test Road to evaluate the behavior of test pavement sections under the influence of traffic load and environmental change. The most important issues in the sensor installation are the accurate location and long-term survivability. They are directly influenced by the sensor installation methodology. The methodology for asphalt strain gages is mainly discussed in this paper because it is the second important sensors in the KHC Test Road project. In order to find the best methodology, we evaluated existing methodology from prior experience and several conducted test installations. We have tried mound, block out, and trench cuts since 2000. Among three methods, block out was the most effective one in terms of accurate location, long-term survivability, and material homogeneity. However, this method cannot be applied to the wearing coarse so that the mound method was used as an alternative. The block out method was applied to base and intermediate layers while the mound method was used to the wearing coarse. Three hundred seventy-four asphalt strain gauges were installed on asphalt pavement sections from September 3rd to November 18th in 2002. According to the sensor measurement evaluation, 6.3% of sensor demonstrated over ranged readings for mound method installation and 2.5% did for block out method installation. We lost only two sensors during the installation. It is 99.5% survival and it is excellent survival rate according to other experience.

• KSCI Review
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• v.2 no.2
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• pp.77-82
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• 1996

도로 정보 시스템은 현재 경찰서 등의 국가 공공 기관 등에서 사용중이며 점차적으로 수도국이나 전기, 전화 등의 사회 공익 단체에서도 사용되어질 전망이다. 본 논문은 도로 정보 시스템의 기본 데이터와 시스템을 이용하여 도로관리에 필수적인 도로 단면도를 생성하기 위한 도로 단면도의 전체적인 디스플레이 구성과 관로나 맨홀 등 지하 매설물의 표현 방법, 각 매설물이 갖고 있는 수치 표현 방법, 각 매설물을 화면에 표현하기 위한 심볼화 작업을 통한 단면도 생성 방법을 제시한다. 또한 매설물의 속성 데이타 표현 방법을 포함하여 도로 단면도 생성에 의한 기대 효과를 고찰한다.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.325-328
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• 2008

본 논문은 '해남-제주간 연계선로 중 지중에 매설된 육상 구간의 HVDC 전력케이블의 정확한 매설경과지 정보 획득'을 목적으로 '해저케이블 탐지 시스템'을 HVDC 전력케이블 육상구간에 적용하여 HVDC 시스템 연차점검 기간 중 #1, #2 연계선로 휴전기간을 이용하여 육상구간 4.2km 2회선 전 구간에 대하여 매설위치 탐지를 실시한 결과를 분석하였다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.2
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• pp.109-121
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• 2003

Lots of various utilities are buried under the surface. The effective management of underground utilities is becoming the very important subject for the harmonious administration of the city. Ground Penetrating Radar(GPR) survey including other various underground survey methods, is mainly used to detect the position and depth of buried underground utilities. However, GPR is not applicable, under the circumstances of shallow depth and places, where subsurface materials are inhomogeneous and are composed of clay, salt and gravels. The aim of this study is to overcome these limitations of GPR and other underground surveys. High-frequency electromagnetic (HFEM) method is developed for the non-destructive precise deep surveying of underground utilities. The method is applied in the site where current underground surveys are useless to detect the underground big pipes, because of poor geotechlical environment. As a result, HFEM survey was very successful in detecting the buried shallow and deep underground pipes and in obtaining the geotechnical information, although other underground surveys including GPR were not applicable. Therefore this method is a promising new technique in the lots of fields, such as underground surveying and archaeology.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.4 s.50
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• pp.15-24
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• 2006

This work reports the results of our study on the dynamic response of various buried pipelines depending on their boundary conditions. We have studied behavior of the buried pipelines both along the axial and the transverse direction. The buried pipelines are modeled as beams on elastic foundation while the seismic wave as a ground displacement in the form of a sinusoidal wave. The natural frequency, its mode, and the effect of parameters have been interpreted in terms of free vibration. In order to investigate the response on the ground wave, the resulting frequency and the mode shape obtained from the free vibration have been utilized to derive the mathematical formula for the forced vibration. The natural frequency varies most significantly by the soil stiffness and the length of the buried pipelines in the case of free vibration. The effects of the propagation direction and velocity and the frequency of ground wave on the dynamic responses of concrete, steel, and FRP pipes have been analyzed and then dynamic responses depending on the type of pipes have been compared. Through performing dynamic analyser for various boundary conditions and estimation of the location of maximum strain has been estimated for the type of pipes and boundary conditions.

• Journal of the Korean GEO-environmental Society
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• v.9 no.6
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• pp.71-79
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• 2008

The underground conduit laid under different environments exhibits various behaviour according to the ground and external load as well as the loading time and conditions, so on. As the environmental conditions are usually different even within the same area, it is very difficult to correctly predict the stress conditions and behaviour of the underground conduit using currently available theoretical analysis. Especially, it is not yet satisfied in Korea for the evaluation of the underground conduit under the influence of the load of vehicles or unexpected loading conditions. Thus, in this study the assessment for the excavation depth and ground disturbance was carried out with a large box model test and numerical analysis. Numerical analysis was also performed for the assessment of dynamic loading conditions like railway load.

• Journal of Korean Society of societal Security
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• v.1 no.4
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• pp.73-81
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• 2008

Electromagnetic induction surveys are one of the useful methods to detect the location and buried depth of underground utilities by measuring horizontal and vertical magnetic fields. It can effectively detects single buried utility with the accuracy of within 20 cm. However when another utility is buried near to target one, the accuracy of utility location considerably decreases due to the distortion of magnetic fields caused from adjacent utility. This study shows the ways to verify the location and buried depth of target utility when magnetic fields does not show symmetric distribution due to adjacent another utility. Using Bluetooth wireless communication tools, we developed the way to records measured magnetic fields to handheld PDA. We investigated the criteria for minimum distance of two adjacent utilities to separate the individual responses through field model test.

• Journal of the Korean Institute of Gas
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• v.15 no.4
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• pp.15-20
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• 2011

This study presents the behavior characteristics of buried three-layered pipeline subjected to pile driving loads corresponding to its cover depth. The analysis considered the driving energy caused by 7 tonf of ram weight and 1.2m of stroke with 20m distance from buried pipeline for all the analysis cases. A cover depth of pipe is varied 0.6m to 3.8m for this research. Vibration Velocity and stress are investigated at the center section in longitudinal direction. With same distance from pile, attenuation ratio of vibration velocity for increment of cover depth has shown an increasing trend. Also, Stress attenuation ratio of inner pipe is increased with cover depth.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.21 no.3
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• pp.237-243
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• 2003

The complicated facilities on the ground have begun to be laid under the ground as increasing emphasis on the beauty of cities due to centralization. But, as the kind of the facilities have been concentrated on the narrow area, accidents occur due to the difficulty of maintenance and the inaccuracy of location information. In this study, first we constructed the field test model to compare with the method of underground probing. So, we could know that the electromagnetic induction method and GPR(Ground Penetration Radar) are useful. It was acquired the position information for the underground facilities using a RTK-GPS. As the result, we have analyzed the accurate position of the underground facility and show the way improving accuracy in detecting and surveying comparing with the traditional surveying method. Also, we hope to contribute the effective maintenance and prevention of disasters to the underground facility as using underground facilities 3D position with Arcview and building the DB of exact depth and underground facilities information system.