• Title/Summary/Keyword: long-term settlement

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Application of EPS Considering Long-term Durability (장기내구성을 고려한 EPS의 현장 적용성)

  • Chun, Byungsik;Jung, Changhee;Ahn, Jinhyun
    • Journal of the Korean GEO-environmental Society
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    • v.8 no.6
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    • pp.53-60
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    • 2007
  • L/EPS, manufactured in the shape of block and used for civil engineering, is a lightweight material with an excellent resistance to compression, and provides a superb self-sufficient stability. EPS is a suitable material capable of resolving the problem of settlement and lateral flow if it is applied as the soil on soft ground. The Korean Standards (KS) has not yet proposed any testing method for use of EPS as an engineering banking material. Only its testing and quality ordinance as a heat insulation material has been standardized. The design criteria for EPS has been established and applied through the trial construction of KHC (Korea Highway Corporation) and quality test of manufacturer, but most studies on them have been confined to factory products. This study is focused on comparing and analyzing long-term durability by conducting cyclic load test, freezing and thawing test, absorption rate test and others. EPS used in the test was chosen from construction sites and factory products, focusing on the long-term durability of EPS depending on the passage of time. Unconfined compression test results indicated that the strength of collected samples was lower than factory products. While the triaxial compression test results indicated that the shear strength increased in proportion to the increase of confining pressure, and factory products had declining shear strength as the confining pressure rose.

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Behavior of Electric Transmission Tower with Rock Anchor Foundation (암반 앵커기초로 시공된 송전철탑 구조물의 거동특성에 관한 연구)

  • Kim, Kyoung-Yul;Hong, Sung-Yun;Lee, Dae-Soo
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.09a
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    • pp.605-614
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    • 2010
  • In this paper, the initial behavior of transmission tower was analyzed. This tower was firstly constructed by rock anchor foundation in domestic 154 kV transmission line and wireless real-time monitoring system was installed to obtain the measured data for analysis of the structure behavior. For this purpose, 16 strain gauges was installed in anchors of foundation and strain gauges, clinometers, anemoscope and settlement sensors was installed at superstructure. As the results, the main factor which influence the behavior of superstructure is wind velocity, wind direction, rainfall and temperature change. Especially, the uplift load at stub of transmission structure revealed about 35.4 percentages of design load. Hereafter the long term stability will be analyzed.

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Stability evaluation of foundation settlement of power transmission tower (송전철탑의 기초침하에 대한 안정성 평가)

  • Lee, Dae-Soo;Cho, Hwa-Kyung;Kim, Dae-Hong;Ham, Bang-Uk
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.687-696
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    • 2005
  • Safety diagnosis was conducted to evaluate the long-term stability evaluation of power transmission tower of which deformation of the upper structural elements occurred. To assess the cause of the structural deformation, field investigation including BIPS, down-hole test, concrete pile coring and finite element analysis were carried out. From these studies, the major cause of deformation was found due to the heavily fractured layer and weathered soil topography at the pile tip area. The cement-milk grouting method was proposed to reinforce these weak zone around the pile tip area. Also, the increase of cross-section and stiffness for steel members of upper tower structures was suggested. Instrumental monitoring was proposed as well to verify reinforcing effect.

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On the Use of Legal Measures to entice Participation in Online Dispute Resolution System (ODR 시스템으로의 사용자 참여유인을 위한 법적 장치의 활용)

  • Kim, Sun-Kwang
    • International Commerce and Information Review
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    • v.10 no.1
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    • pp.279-293
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    • 2008
  • The number of participants in an online dispute resolution(ODR) system is crucial to its survival. Securing participation is nonetheless difficult. Clearly, it is important to offer a system that is fair, transparent and offers an efficient service at low cost. These factors are fundamental to ensure trust and to build a returning customer base to the system, but are not what attracts a party to submit a dispute for settlement. This paper describes and discusses four main categories of legal measures found in the online dispute resolution services offered by SquareTrade and WIPO. In spite of shortcomings in the offered, the legal measures have contributed to attract large numbers of participants. Large participation secures the long-term economic viability of an online dispute resolution system. The four categories of legal measures described and discussed in this paper need to be part of the specifications and the design and development of future ODR system.

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Groundwater Flow model of Drawdown and Recovery Due to Watertight Tunnel Excavation and Design Example for Lining (터널시공에 따른 지하수위 변화의 모델링과 이를 고려한 완전방수 터널의 라이닝 설계 예)

  • 남기천;이형원;배정식;나경웅
    • Tunnel and Underground Space
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    • v.4 no.1
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    • pp.24-30
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    • 1994
  • Although a dry-system tunnel is not good for reasons fo economy and construction, it has been applied to some tunnels under construction owing to the advantages of good long-term maintenance of tunnel, prevention of consolidation settlement due to the drawdown of groundwater, preservation of the ecosystem, cutailment of operation cost, and so on. The stability of groundwater and the change of the applied water pressure after water proofing were analysed by the finite element method. Using this result, an example of designing the secondary lining for the dry-system tunnel which is to be constructed in low-permeability hard rock was presented.

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Evaluation of Yield Load in Pile Load Tests on Driven Piles (관입말뚝에 대한 연직재하시험시 항복하중의 판정법)

  • 홍원표;심기석
    • Geotechnical Engineering
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    • v.5 no.1
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    • pp.7-18
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    • 1989
  • In pile load tests on end bearing piles, generally, it is not possible to continue loading to the ultimate load. Thus, the concept of yield load has been introduced for determining design loads Iron the pile load test records. The conventional rules to determine the yield load were not available for evaluation on pile load test records obtained in 6 fields nearby westers 8r Southern Coasts in Korea. A new rule 9.as presented to determine easily the yield load, based on investigations on the pile load test records. The yield load of piles is determined at the infiection point on semi-logarithmic coordinates (P-logS), in which load is plotted in normal scale and settlement is plotted in logarithmic scale. This method may not only save much costs and times but also present safe luorking circumstances for pile load tests in field. It was found that the yield load represented the elastic limit of the pile load-settlement behalf.iota. The ultimate load, which is given at 25.4mm settlement on pile head, was 1.5 times of the yield load. The allowable long-term and short-term load capacities were, respectively, 50% and 75% of the yield load. The safety factors to get the allowable pile capacity were obtained as 2.0~4.0 for the equations to predict the static pile capacity.

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A Study on the Diagnostic Model of Cross-national Digital Divide (국가간 정보격차 진단 모형 개발에 관한 연구)

  • Lee, Hohyung
    • Journal of Information Technology and Architecture
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    • v.11 no.1
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    • pp.99-111
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    • 2014
  • Today, through developing country's Official Development Assistance (ODA) project, Republic of Korea is giving help in establishing communication networks, furnishing PCs and etc, as a help of information base expansion. And to resolve digital divide between countries, Republic of Korea's IT service group dispatch business has also significantly contributed to enhance information application level of developing countries. The conclusion and suggestion of this study is as follow. It is obvious that utilization of information can be affected by capability improvement of developing country's informatization level. However, developing informatization strategy level and environment in long term wise will cause greater influence than to raise immediate informatization base level. Overall, settlement of long term digital divide seems possible when we elevate developing countries' informatization strategy level and environment.

Assessment of The Priority Order of Monitoring Devices on Maintenance for The Long-Term Safety of Existing Fill Dam (기존 필댐 장기간 안전관리를 위한 계측항목 유지보수 우선순위 산정)

  • Lee, Jongwook;Jeon, Jaesung;Lim, Heuidae
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.7
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    • pp.67-79
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    • 2009
  • Although readjustment of monitoring system for existing fill dam maintenance is needed by the sustainable increasing of the abandonment rate of monitoring devices by malfunction through the life-cycle of dam, monitoring plans for long-term dam safety has relied on the experience and the opinion of minor expert group without systematic and quantitative analysis on the failure modes and the priority order of monitoring devices on maintenance. In this study the priority order of monitoring devices of existing 5 fill dams was evaluated quantitatively based on the preceding study (Andersen et al, 1999) and the result recommended the establishment of real-time monitoring system for seepage, pore pressure and crest settlement as the readjustment plan for existing fill dam monitoring system. This readjustment plan matches well with the recommendation of PWRI (1984), JCOLD (1986) and the results from Bagherzadeh-Khakkahali and Mirghasemi (2005).

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Real-scale Accelerated Testing to Evaluate Long-term Performance for Bridge/Earthwork Transition Structure Reinforced by Geosynthetics and Cement Treated Materials (토목섬유와 시멘트처리채움재로 보강한 교량/토공 접속구조의 장기공용성 평가를 위한 실물가속시험)

  • Lee, Il-Wha;Choi, Won-Il;Cho, Kook-Hwan;Lee, Kang-Myung;Min, Kyung-Chan
    • Journal of the Korean Society for Railway
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    • v.17 no.4
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    • pp.251-259
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    • 2014
  • The transition zone between an earthwork and a bridge effect to the vehicle's running stability because support stiffness of the roadbed is suddenly changed. The design criteria for the transition structure on ballast track were not particular in the past. However with the introduction of concrete track is introduced, it requires there is a higher performance level required because of maintenance and running stability. In this present paper, a transition structure reinforced with geosynthetics is suggested to improve the performance of existing bridge-earthwork transition structures. The suggested transition structure, in which there is reinforcing of the approach block using high-tension geosynthetics, has a structure similar to that of earth reinforced abutments. The utilized backfill materials are cement treated soil and gravel. These materials are used to reduce water intrusion into the approach block and to increase the recycling of surplus earth materials. An experiment was performed under the same conditions in order to allow a comparison of this new structure with the existing transition structure. Evaluation items are elastic displacement, cumulative settlement, and earth pressure. As for the results of the real-scale accelerated testing, the suggested transition structure has excellent performance for the reduction of earth pressure and settlement. Above all, it has high resistance the variation of the water content.

Prehistoric subsistence and pottery use in the ancient Korean Peninsula: New evidence from organic geochemical analysis of potsherds (토기 내 잔존유기물을 활용한 한반도 선사·고대의 토기 사용과 식생활에 관한 연구)

  • Kwak, Seungki;Shin, Sookjung
    • Korean Journal of Heritage: History & Science
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    • v.52 no.3
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    • pp.146-159
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    • 2019
  • This study focuses on the understanding of human subsistence and pottery use during ancient times on the Korean peninsula through lipid analysis of potsherds from several major prehistoric settlement sites. Ancient human subsistence has been one of the long-standing topics in Korean archaeology. However, since the high acidity of sediments does not allow long-term preservation of organic remains, we still lack some critical information related to the prehistoric diet. Pottery contains relatively well-preserved organic remains created during past cooking events. Though pottery is one of the most studied material cultures in Korean archaeology, almost no attention has been given to analyzing the pottery itself. This is a surprising omission and represents a serious gap in our understanding of prehistoric technology and subsistence. The analysis of ancient lipids extracted from the pottery matrix using GC-MS and isotope analysis can contribute to our understanding of the true nature of past subsistence strategies. Potsherd samples for the analyses in this study were collected from six prehistoric and early historic settlement sites located in the central part of the Korean peninsula. The results showed that subsistence strategies differed by both location and time period. For example, at Jungdo, an inland open-air Bronze Age settlement site in Chuncheon City, we were able to see the presence of terrestrial mammals. At Gahak-dong, Gwangmyeong City, marine resources were utilized, as the location of the site is not far from the coastline. At the early historic site of Guwol-dong, Incheon City, we were able to detect dairy products. The results of this study suggest that there was utilization of a wider range of resources among ancient dwellers in the central part of the Korean peninsula.