• Title/Summary/Keyword: geo-field

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A Study on Mechanical Properties and Applicability of CNT-Mixed Grout (CNT-Mixed grout의 역학적 특성 및 적용성 연구)

  • Kim, Seunghyun;Kim, Kanghyun;Shin, Jongho
    • Journal of the Korean GEO-environmental Society
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    • v.23 no.9
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    • pp.5-16
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    • 2022
  • In recent years due to the development of urban and underground space, the number of ground disasters is increasing, and it is also leading to social problems. To solve the problem, a grouting method is generally used. However, the grouting method has material (grout) limitations in permeability, gelation properties and tensile resistance. Therefore, research on grout materials mixed with fibers is actively carried out to improve the problems. However, in the actual ground injection process, many difficulties have been faced causing the blockage of the inlet port and the injection tube. In this study, 'CNT-mixed grout material' was developed using CNT powder that can reinforce the tensile strength of soils. The uniaxial compressive and tensile strength tests were performed to obtain the optimal content and mechanical properties of the CNT Powder-mixed grout. It was found that the optimal CNT powder content is 0.5% that gives the average maximum strength. A one-dimensional injection test and the bulb formation test were carried out, and it was identified that the injection rate and bulb form could be controlled by pressure and mixing ratio. Field application of the CNT-Mixed grout is simulated using numerical analysis of slopes, foundations, and tunnels reinforced in several types. The positive effect of reducing plastic ranges and settlements was confirmed.

A Study on the Field Application of a Small Dynamic Cone Penetration Tester Using Hammer Automatic Strike and Penetration Measurement (해머 타격과 관입량 측정이 자동화된 소형 동적콘관입시험기의 현장 적용성 연구)

  • Hwiyoung Chae ;Soondal Kwon
    • Journal of the Korean GEO-environmental Society
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    • v.24 no.12
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    • pp.5-11
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    • 2023
  • Economic damage is occurring due to landslides and debris flows that occur when the ground artificially created for roads or photovoltaic power generation facilities is weakened by rainfall such as torrential rain. In order to understand the stability of the artificially created ground, it is very important to check the ground information such as the compositional state and mechanical characteristics of the stratum. However, since most of the investigation sites are steep slopes or there are no access roads, it is not easy to enter the drilling equipment commonly used to check ground information and perform standard penetration tests. In this study, a dynamic cone penetration test (DCP) device using a miniaturized auger drilling equipment and an automatic drop device was developed to check the cone resistance value and the dynamic cone penetration test value and analyze the correlation with the standard penetration test value to confirm its applicability at the mountain solar power generation site. As a result, the cone resistance value is qd = 0.46 N and the dynamic cone penetration test value is Nd = 1.58 N, confirming a value similar to the results of existing researchers to secure its reliability.

Survey of coastal topography using images from a single UAV (단일 UAV를 이용한 해안 지형 측량)

  • Noh, Hyoseob;Kim, Byunguk;Lee, Minjae;Park, Yong Sung;Bang, Ki Young;Yoo, Hojun
    • Journal of Korea Water Resources Association
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    • v.56 no.spc1
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    • pp.1027-1036
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    • 2023
  • Coastal topographic information is crucial in coastal management, but point measurment based approeaches, which are labor intensive, are generally applied to land and underwater, separately. This study introduces an efficient method enabling land and undetwater surveys using an unmanned aerial vehicle (UAV). This method involves applying two different algorithms to measure the topography on land and water depth, respectively, using UAV imagery and merge them to reconstruct whole coastal digital elevation model. Acquisition of the landside terrain is achieved using the Structure-from-Motion Multi-View Stereo technique with spatial scan imagery. Independently, underwater bathymetry is retrieved by employing a depth inversion technique with a drone-acquired wave field video. After merging the two digital elevation models into a local coordinate, interpolation is performed for areas where terrain measurement is not feasible, ultimately obtaining a continuous nearshore terrain. We applied the proposed survey technique to Jangsa Beach, South Korea, and verified that detailed terrain characteristics, such as berm, can be measured. The proposed UAV-based survey method has significant efficiency in terms of time, cost, and safety compared to existing methods.

Meta-analysis of Site Distribution and Researcher Network of the Korean Society of Limnology: 1968~2017 (한국 육수학 연구지 분포의 메타분석과 연구자 네트워크 변화: 1968~2017)

  • Kim, Ji Yoon;Joo, Gea-Jae;Do, Yuno
    • Korean Journal of Ecology and Environment
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    • v.51 no.1
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    • pp.124-134
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    • 2018
  • We analyzed research topics, temporal distribution of field sites, and researcher network of 1,508 limnology publications in the Korean Journal of Limnology (1968~2012) and the Korean Journal of Ecology and Environment (2013~2017). We found that water quality and sediment, phytoplankton, invertebrates, and fish were major subjects during the study periods. Survey of flora and fauna and physiological experiment of freshwater species were the largest subjects during 1970~80s, while other subjects including production, behavior, modeling, and ecological assessment have been rapidly increased since the 1990s. Most of the biological taxa equally studied lotic and lentic system, however, invertebrates and fish related studies more focused on the lotic system. Spatially, the field site of Korean limnology studies was found to be concentrated in main river channels runs through urban areas and artificial lakes than preserved natural areas. Freshwater system, located at the elevation range of 301~400 m (upstream of main channels), had the lowest number of field sites. Collaboration among researchers and different institution types have been steadily increased and expanded as the number of publications increased.

Development of a Suitability Analysis System for Wind Energy Facilities Using 3D Web GIS (3차원 Web GIS 기반 풍력에너지 시설물 적지분석 시스템 개발)

  • Kim, Kwang-Deuk;Yun, Chang-Yeol;Jo, Myung-Hee;Kim, Sung-Jae
    • Journal of the Korean Association of Geographic Information Studies
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    • v.15 no.3
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    • pp.81-90
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    • 2012
  • Recently, with an increased social interest in new and renewable energy resources, together with rapid advancement in IT(information technology) and spatial information technology, there have recently been a lot of attempts to find out methods to make systematic and scientific use of information technology and spatial information technology, depending upon a fusion with GIS(Geographic Information System) spatial information technology in the field of new and renewable energy. This paper developed a suitability analysis system to conduct a correct and precise analysis of an ideal place for wind energy facilities in comprehensive consideration of topographic, economic, and cultural environments. It also used recent spatial information technology including 3D GIS to develop a supportive system for an analysis and decision making of an ideal place for 3D Web GIS-based wind energy facilities like a precise field information implementation, a 3D result display, a 3D object implementation, simulation, and so on. These systems make it possible to build scientific new-renewable energy facilities, to collect, manage and analyze information in an accurate and quantitative manner. In addition, they help serve as a turning point for the construction of a real-time information supply system. Furthermore, they can support rational decision making by making it possible to analyze a variety of forms of field information through building a system for the management of 3D image-based information on new-renewable energy resources.

Estimation of Shear Plane at Failed Landfill Using Field and Laboratory Tests (현장 및 실내실험을 이용한 매립지 전단활동면 추정에 대한 연구)

  • Choi, Hoseong;Kim, Tae-Hyung;Kim, Sung-Wook
    • The Journal of Engineering Geology
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    • v.29 no.3
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    • pp.315-327
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    • 2019
  • Back analysis has been used to evaluate the factor of safety and circular failure plane at the landfill failure site. However, the estimated circular failure plane by back analysis is quite different from what is observed in the field. Thus, this study was conducted to estimate an actual shear failure plane inside the ground which gives a more accurate failure plane. Cone penetration test (CPT), boring test, soft X-ray image scan, density logging, and ultrasonic logging were conducted at the field and laboratory. The result of CPT showed significantly lower cone resistance, pore pressure, and undrained shear strength at a particular part. This part is a possible shear failure plane inside the ground. To validate, the soft X-ray scan images were analyzed and found the disturbed (inclined) bedding plane induced by shear activity at the estimated shear failure plane. Density and ultrasonic logging tests also found a similar result. Thus, the method in this study is possible to estimate the shear failure plane inside the ground.

Standard Procedures and Field Application Case of Constant Pressure Injection Test for Evaluating Hydrogeological Characteristics in Deep Fractured Rock Aquifer (고심도 균열암반대수층 수리지질특성 평가를 위한 정압주입시험 조사절차 및 현장적용사례 연구)

  • Hangbok Lee;Chan Park;Eui-Seob Park;Yong-Bok Jung;Dae-Sung Cheon;SeongHo Bae;Hyung-Mok Kim;Ki Seog Kim
    • Tunnel and Underground Space
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    • v.33 no.5
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    • pp.348-372
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    • 2023
  • In relation to the high-level radioactive waste disposal project in deep fractured rock aquifer environments, it is essential to evaluate hydrogeological characteristics for evaluating the suitability of the site and operational stability. Such subsurface hydrogeological data is obtained through in-situ tests using boreholes excavated at the target site. The accuracy and reliability of the investigation results are directly related to the selection of appropriate test methods, the performance of the investigation system, standardization of the investigation procedure. In this report, we introduce the detailed procedures for the representative test method, the constant pressure injection test (CPIT), which is used to determine the key hydrogeological parameters of the subsurface fractured rock aquifer, namely hydraulic conductivity and storativity. This report further refines the standard test method suggested by the KSRM in 2022 and includes practical field application case conducted in volcanic rock aquifers where this investigation procedure has been applied.

An Effect of Aggregation of Point Features to Areal Units on K-Index (점사상의 지역단위 집계가 K-지표에 미치는 영향)

  • Lee Byoung-Kil
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.1
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    • pp.131-138
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    • 2006
  • Recently, data gathering and algorithm developing are in progress for the GIS application using point feature. Several researches prove that verification of the spatial clustering and evaluation of inter-dependencies between event and control are possible. On the other hand, most of the point features as GIS data are gathered by indirect method, such as address geo-coding, rather than by direct method, such as field surveying. Futhermore, lots of statistics by administrative district based on the point features have no coordinates information of the points. In this study, calculating the K-index in GIS environment, to evaluate the effect of aggregation of raw data on K-index, K-indices estimated from raw data (parcel unit), topographically aggregated data (block unit), administratively aggregated data (administrative district unit) are compared and evaluated. As a result, point feature, highly clustered in local area, is largely distorted when aggregated administratively. But, the K-indices of topographically aggregated data is very similar to the K-indices of raw data.

Structuralistic Analysis for Establishment of Concept and Variables of Shanghan Diseases (상한병(傷寒病)의 개념(槪念)과 논치근거(論治根據) 확립을 위한 구조주의적 분석)

  • Chi, Gyoo Yong
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.29 no.2
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    • pp.127-132
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    • 2015
  • In order to grasp the clear concepts and variables to treat Shanghan diseases which has complex meaning by each medical literature, several concepts and analytic method of structuralism from early to late stage encompassing Saussure and Derrida were used. Main concepts are langue and parole, signifiant and signifie, syntagme and paradigme, denotation and connotation, synchronie and diachronie, identity of structure and differance etc. and methods are substituting these concepts to historical Shanghan theories from Zhongjing to Ming-Qing dynasty and comparisons of synchronie about their era. Essential qualities of Shanghan diseases are pathologic phenomena under the order of unification of nature and man formed through concrescence between individual human body and geo-climatico-socio-cultural environmental conditions, neither injuries by cold pathogen nor five types of exopathogenic febrile diseases. The former environmental elements can be inferred from general traits of desires and public pathological aspects of social members, and the latter personal factors from corresponding features to those pathogenic variables. In addition, the concepts of Shanghan disease are added successively up to now via Jin-Yuan's four great masters and Wenbing masters, and thus the new concepts of denotation became another connotation obtaining new signifiant. In this way, for the treatment of Shanghan diseases, new theories should be made for ranging prescription over the wenbing field; reflecting not only climatical variables but also each patient's physio-pathological features and sociocultural variables. Thereby an appropriate and reasonable therapeutical systems can be designed and can guide research direction hereafter.

The impact of municipal waste disposal of heavy metals on environmental pollution: A case study for Tonekabon, Iran

  • Azizpour, Aziz;Azarafza, Mohammad;Akgun, Haluk
    • Advances in environmental research
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    • v.9 no.3
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    • pp.175-189
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    • 2020
  • Municipal solid waste disposal is considered as one of the most important risks for environmental contamination which necessitates the development of strategies to reduce destructive consequences on the ecosystem as related especially to heavy metal accumulation. This study investigates heavy metal (i.e., As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn) accumulation in the Tonekabon region, NW of Iran that is related to city waste disposal and evaluates the environmental impact in the Caspian Sea coastal region. For this purpose, after performing field studies and collecting 50 soil specimens from 5 sites of the study area, geochemical tests (i.e., inductively coupled plasma mass spectrometry, atomic absorption spectroscopy and x-ray fluorescence) were conducted on the soil specimens collected from the 5 sites (named as Sites A1, A2, A3, A4 and A5) and the results were used to estimate the pollution indices (i.e., geo-accumulation index, normalized enrichment factor, contamination factor, and pollution load index). The obtained indices were utilized to assess the eco-toxicological risk level in the landfill site which indicated that the city has been severely contaminated by Cu, Mn, Ni, Pb and Zn. These levels have been developed along the stream towards the nearshore areas indicating uptake of soil degradation. The heavy metal contamination was classified to range from unpolluted to highly polluted, which indicated serious heavy metal pollution in the study area as related to municipal solid waste disposal in Tonekabon.