• Title/Summary/Keyword: dam foundation

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The effects of scour depth and riverbed condition on the natural frequencies of integral abutment bridges

  • Akbari, Reza;Maadani, Saeed;Abedi, Alireza;Maalek, Shahrokh
    • Structural Monitoring and Maintenance
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    • v.6 no.2
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    • pp.85-101
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    • 2019
  • The effects of foundation scour depth and riverbed condition on the natural frequencies of a typical cross-river integral abutment bridge have been studied. The conventional operational modal analysis technique has been employed in order to extract the modal properties of the bridge and the results have been used in the Finite Element (FE) model updating procedure. Two tests have been carried out in two different levels of water and wet condition of the riverbed. In the first test, the riverbed was in dry condition for two subsequent years and the level of water was 10 meter lower than the natural riverbed. In the second test, the river was opened to water flow from the upstream dam and the level of water was 2 meter higher than the natural riverbed. The results of these two tests have also been used in order to find to what extend the presence of water flow in the river and saturation of the surrounding soil affect the bridge natural frequencies. Finally, the updated FE model of the bridge has been applied in a series of parametric analyses incorporating the effect of piles' relative scour depth on the bridge natural frequency of the first four vibration modes.

The Strategy for the Advancement of Groundwater Management in Korea (국내 지하수 통합관리 선진화 전략)

  • Kang, Sunggoo;Kim, Jiwook;Choi, Yongjun;Park, Minyoung;Park, Hyunjin;Lee, Jinkwan
    • Journal of Soil and Groundwater Environment
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    • v.27 no.2
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    • pp.36-40
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    • 2022
  • To respond to rapidly changing water circumstances such as climate change, drought, etc., the korean government (MOE) established four advanced strategies for integrated groundwater management. The first strategy is watershed-based management of groundwater. The second strategy is total quantity management of groundwater including improvement of groundwater preservation area policy and procedure of investigation for groundwater influence area, additional construction of groundwater dam, installation of large-scale public wells, extention of spilled groundwater use. The third strategy is prevention of groundwater contamination including expansion of monitoring wells, introducing declaration of groundwater contamination. The last strategy is advancement of groundwater information management including integrated management of data, setting up a big-data based open platform. The above-mentioned four strategies will be reflected in the 4th National Groundwater Management Plan to secure implementation power, and it is expected to laid the foundation for advanced and rational groundwater management system.

Assessment of Partial Safety Factors for Limit States Design of Foundations (한계상태설계법의 기초설계 적용을 위한 부분안전계수의 평가)

  • Kim Bum-Joo
    • Journal of the Korean Geotechnical Society
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    • v.20 no.9
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    • pp.77-89
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    • 2004
  • While limit states design (LSD) is currently the standard structural design practice, it is relatively new in the geotechnical design. Adoption of LSD far geotechnical design is an international trend. In the present study, various LSD codes from the United States, Canada, and Europe were reviewed. A simple first-order-second-moment (FOSM) reliability analysis was performed to determine theoretically the ranges of load and resistance factor values for representative loads and foundation bearing capacity, respectively. In order for foundation design to be consistent with current structural design practice, it would be desirable to use the same loads, load factors and load combinations. The values of load factor, obtained from the FOSM analysis, were found to be generally consistent with those given in the codes, whereas the values of resistance factor indicated overall lower ranges due to high values of coefficient of variation used in the analysis. Since the degree of uncertainties included in bearing capacity of foundations varies with the methods used to estimate the bearing capacity, different values of resistance factor should be used fur different methods. For the purpose, continuous efforts are needed to be made first to accurately identify and quantify the uncertainties in the methods.

Evaluation of GIS-based Soil Loss Amount in Considering Basin Characteristics (유역특성을 고려한 GIS 기반 토양침식량 평가)

  • Guak Dong-Wook;Cho Gi-Sung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.24 no.1
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    • pp.89-97
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    • 2006
  • Soil erosion has caused serious environmental problems which threaten the foundation of natural resources. In this paper, we chose RUSLE erosion model, which could be connected easily with GSIS and available generally in mid-scale watershed among soil erosion models, and extracted factors entered model by using GSIS spatial analysis method. First, this study used GIS database as soil map, DEM, land cover map and rainfall data of typhoon Memi (2003) to analyze soil loss amount of Dam basin. To analyze the changes of soil loss in considering basin characteristics as up-, mid- and downstream, this study calculated soil erodibility factor (K), topographic factors (LS), and cover management factor (C). As a result of analysis, K and LS factors of upstream showed much higher than those of downstream because of the high ratio of forest. But C factor of downstream showed much higher than that of upstream because of the high ratio of agricultural area. As a result of analysis of soil loss, unit soil loss of upstream is 4.3 times than soil loss of downstream. Therefore, the establishment of countermeasures for upstream is more efficient to reduce soil loss.

Reproductive Performance of Three Iranian Sheep Breeds

  • Kiyanzad, M.R.;Panandam, J.M.;Emamjomeh Kashan, N.;Jelan, Z.A.;Dahlan, I.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.1
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    • pp.11-14
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    • 2003
  • To evaluate the ewe reproductive performances of three Iranian local sheep breeds, namely Moghani, Chal and Zel, 27 rams and 473 ewes were used as the foundation flock in a crossbreeding program. The three breeds were crossed amongst themselves reciprocally. Ram breed and ewe breed showed a two-way interaction on apparent fertility. The Zel ewes showed higher fertility than the Chal and Moghani ewes (94.4 vs 77.3 and 84.6%). Prolificacy among main and individual mating groups were not significantly different (p>0.05). Zel ewes were 22.3 and 14.8% more reproductive (p<0.05) than Chal and Moghani ewes, respectively. Zel and Moghani ewes showed higher (p<0.05) ewe productivity than Chal ewes. Ram breed had a significant (p<0.05) effect on ewe efficiency. The Zel rams were not completely successful to mate with Chal ewes, this caused a to way-interaction between ram and ewe breeds. The Zel ewes mated with Chal and Moghani rams showed 26.1 and 28.5% more efficiency than those mated with Zel rams. This observation strongly supports the use of crossbreeding to improve the efficiency of the Zel ewes. With decreasing lamb mortality, through supplemented feeding of lambs in pre-weaning period, and increasing litter weight, through crossbreeding, it should be possible to improve the efficiency of Zel ewes even better than Chal and Moghani ewes. Small body size of Zel ewes that needs the lower maintenance requirements would be a well advantageous to using Zel ewes as the dam herd to produce commercial lambs in north area of Iran.

Characteristics of Shear Behavior According to State of Particle Bonding and Crushing (입자 결합 및 파쇄 형태에 따른 전단거동 특성)

  • Jeong, Sun-Ah;Kim, Eun-Kyung;Lee, Dong-Seok;Lee, Seok-Won
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.314-323
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    • 2010
  • Recently, granular soils having a large particle size are frequently used as a filling material in the construction of foundation, harbor, dam, and so on. The shear behavior of this granular soil plays a key role in the stability of structures. For example, soil particle crushing occurring at the interface between structure and soil and/or within soil mass can cause the disturbance of ground characteristics and consequently induce an issues in respect of stability of structures. In order to investigate the shear behavior according to an existence and nonexistence of particle crushing, numerical analyses were conducted by using the DEM(Discrete Element Method)-based software program PFC(Particle Flow Code). Using the crushing model and non-crushing model which were created in this study, numerical analyses of ring shear test were conducted and their results were analyzed and compared. In general, landslide and slope stability are accompanied by a large displacement and consequently not only a peak strength but also a residual strength are very important in the analysis of landslide and slope stability. However the direct shear test which has been commonly used in the determination of shear strength parameters has a limitation on displacement therefore the residual strength parameters can not be obtained. The characteristics of residual shear behavior were investigated through the numerical analyses in this study.

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3D imaging of fracture aperture density distribution for the design and assessment of grouting works (절리 암반내 그라우팅 설계 및 성과 판단을 위한 절리틈새 밀도 분포의 3차원 영상화 연구)

  • Kim, Jung-Yul;Kim, Yoo-Sung;Nam, Ji-Yeon
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.113-120
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    • 2004
  • Grouting works in fractured rocks have been performed to reinforce the underground and/or to block ground water flow at the foundation site of dam, bridge and so on. For the efficient grouting design, a prior knowledge of the fracture pattern of underground area to be grouted in very important. For the practical use, aperture sizes of open fractures that will be filled up with grouting materials will be kind of valuable information. Thus, the main purpose of this study is to develop a new technique (so called "GenFT") enable to form a three dimensional image of fracture aperture density distribution from Televiewer data. For this, the study is to focus on dealing with (1) estimating aperture size of each fracture automatically from Televiewer time image, (2) mapping extension of fracture planes on a given section, (3) evaluating aperture density distribution on the section by using both aperture size and fracture face mapping result of each fracture, (4) developing an algorithm that can transfer the previous results to any arbitrary(vertical and/or horizontal) section around the borehole. Since 3D imaging means "a strategy used to form an image of arbitrarily subdivided 2D sections with aperture density distribution", it will help avoid ambiguities of fracture pattern interpretation and hence will be of practical use not only for the design and assessment of grouting works but also for various engineering works. Examples of fields experiments are illustrated. It would seem that this technique might lead to reflecting future trend in underground survey.

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Design of Idle-time Measurement System for Data Spoofing Detection (데이터 스푸핑 탐지를 위한 유휴 시간 측정 시스템 설계)

  • Jung, Sung-Mo;Song, Jae-Gu;Kim, Tai-Hoon;So, Yo-Hwan;Kim, Seok-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.1
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    • pp.151-158
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    • 2010
  • The industrial foundation of the inside and outside of a country has brought significant damages due to attacks from hackers. Especially, if the national primary core infrastructures(like electric power, dam, railroad, atomic energy, etc.) has been significantly damaged, it can be directly linked not only to economic problems but also to people's lives. These national primary core infrastructures usually constitute SCADA system using Modbus RS486 communication. Because of this characteristic, SCADA system has RTU master and slave linked to RJ11 cables to directly pass commands. RJ11 is possible in data spoofing using physical connection because the transmission range of RJ11 has a wide bandwidth(almost 1km). Hence, this paper designed an idle-time measurement system for SCADA system for emerging security improvement in the national primary core infrastructures.

Anti-Inflammatory, Antioxidant, Anti-Angiogenic and Skin Whitening Activities of Phryma leptostachya var. asiatica Hara Extract

  • Jung, Hyun-Joo;Cho, Young-Wook;Lim, Hye-Won;Choi, Hojin;Ji, Dam-Jung;Lim, Chang-Jin
    • Biomolecules & Therapeutics
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    • v.21 no.1
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    • pp.72-78
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    • 2013
  • This work aimed to assess some pharmacological activities of P. leptostachya var. asiatica Hara. The dried roots of P. leptostachya var. asiatica Hara were extracted with 70% ethanol to generate the powdered extract, named PLE. Anti-angiogenic activity was detected using chick chorioallantoic membrane (CAM) assay. In vitro anti-inflammatory activity was evaluated via analyzing nitric oxide (NO) content, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells. Antioxidant activity was determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and reactive oxygen species (ROS) level in the stimulated macrophage cells. Matrix metalloproteinase-9 (MMP-9) and -2 (MMP-2) activities in the culture media were detected using zymography. PLE exhibits an anti-angiogenic activity in the CAM assay, and displays an inhibitory action on the generation of NO in the LPS-stimulated macrophage cells. In the stimulated macrophage cells, it is able to diminish the enhanced ROS level. It can potently scavenge the stable DPPH free radical. It suppresses the induction of iNOS and COX-2 and the enhanced MMP-9 activity in the stimulated macrophage cells. Both monooxygenase and oxidase activities of tyrosinase were strongly inhibited by PLE. Taken together, the dried roots of P. leptostachya var. asiatica Hara possess anti-angiogenic, anti-inflammatory, antioxidant and skin whitening activities, which might partly provide its therapeutic efficacy in traditional medicine.

Basic Study on the Image Instrument of the Facial-form by the 3D-facial Scanner (얼굴스캐너를 활용한 안면형상 영상진단기의 기초 연구)

  • Kim, Gyeong-Cheol;Lee, Jeong-Won;Kim, Hoon;Shin, Soon-Shik;Lee, Hai-Woong;Lee, Yong-Tae;Chi, Gyoo-Yong;Kim, Jong-Won
    • Journal of Physiology & Pathology in Korean Medicine
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    • v.22 no.2
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    • pp.497-501
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    • 2008
  • 3D facial scanner for an accurate analysis is measured precisely a distance in straight, a distance in curved line, an angle in 3D data, the area of surface. We can easy acquire 3D data by the method of 0.8sec in each scan with easy handling, simple merge to whole face, harmless and fast process. In the HyungSang medicine, the inspection of the facial shape includes the Dam(gall bladder) - Bang Kwang(urinary bladder) body, the Jung${\cdot}$Gi${\cdot}$Shin${\cdot}$Hyul, the six merdian types etc. And we will collect the evidence based date verifing in the HyungSang clinical medicine. As we will analyze the facial whole form and the size${\cdot}$length${\cdot}$angle of the facial part, put the facial form's standardization on a solid foundation.