• 제목/요약/키워드: Dam process

검색결과 293건 처리시간 0.022초

Depositional Environment and Distribution of Heavy Metal off the Shihwa Dam

  • Oh, Jae-Kyung
    • Journal of the korean society of oceanography
    • /
    • 제32권3호
    • /
    • pp.120-127
    • /
    • 1997
  • Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.

  • PDF

Assessment of Future Climate Change Impact on DAM Inflow using SLURP Hydrologic Model and CA-Markov Technique

  • Kim, Seong-Joon;Lim, Hyuk-Jin;Park, Geun-Ae;Park, Min-Ji;Kwon, Hyung-Joong
    • 대한원격탐사학회지
    • /
    • 제24권1호
    • /
    • pp.25-33
    • /
    • 2008
  • To investigate the hydrologic impacts of climate changes on dam inflow for Soyanggangdam watershed $(2694.4km^2)$ of northeastern South Korea, SLURP (Semi-distributed Land Use-based Runoff Process) model and the climate change results of CCCma CGCM2 based on SRES A2 and B2 were adopted. By the CA-Markov technique, future land use changes were estimated using the three land cover maps (1985, 1990, 2000) classified by Landsat TM satellite images. NDVI values for 2050 and 2100 land uses were estimated from the relationship of NDVI-Temperature linear regression derived from the observed data (1998-2002). Before the assessment, the SLURP model was calibrated and verified using 4 years (1998-2001) dam inflow data with the Nash-Sutcliffe efficiencies of 0.61 to 0.77. In case of A2 scenario, the dam inflows of 2050 and 2100 decreased 49.7 % and 25.0 % comparing with the dam inflow of 2000, and in case of B2 scenario, the dam inflows of 2050 and 2100 decreased 45.3 % and 53.0 %, respectively. The results showed that the impact of land use change covered 2.3 % to 4.9 % for the dam inflow change.

필댐의 3차원 기하 효과에 따른 전기비저항 왜곡 효과 분석 (Analysis of distortion effect of resistivity data due to 3D geometry of fill dam)

  • 오석훈;김형수
    • 한국지구물리탐사학회:학술대회논문집
    • /
    • 한국지구물리탐사학회 2005년도 공동학술대회 논문집
    • /
    • pp.55-58
    • /
    • 2005
  • CFRD (콘크리트 표면 차수벽형 석괴댐)에서 수행한 전기비저항 탐사 결과, 하부에서 매우 낮은 비저항대가 관측되었다. 일반적으로 CFRD 형식의 댐은 내부 포화가 발생하지 않는 것으로 알려져 있으나, 금번 조사에서 하부 20m 깊이에서 일정하게 저비저항대가 발견되어 이에 대한 검토를 위해 3차원 해석을 수행하였다. 탐사 당시의 수위는 댐 정상부에서 10m 정도 내려가 있는 상태였다. 첫 탐사 이후 6개월이 지난 후에 이루어진 탐사에서도 비슷한 양상을 보이고 있었다. 이에 대한 해석을 위해서 조사 댐의 모양을 대상으로 3차원 순산 모델링을 수행하고, 이에 대한 2차원 역산 해석을 적용하여 기존 해석 방법의 오류 가능성을 검토하였다. 또한 비저항 조사가 많이 적용된 중심코아 형 댐의 경우의 사례와 비교하였다. 해석 결과, 3차원 댐체 구조에 대한 2차원 역산 해석은 저수부의 수위와 밀접한 관련을 갖는 것으로 보이며, 3차원의 사다리꼴 기하구조로 인하여 댐 내부에 비저항의 이상대가 존재할 경우에도 그 민감도가 떨어지는 것으로 분석되었다.

  • PDF

필댐의 3차원 기하 효과에 따른 전기비저항 왜곡 효과 분석 (Analysis of Distortion Effect of Resistivity Data Due to 3D Geometry of Fill Dam)

  • 오석훈;김형수
    • 지구물리
    • /
    • 제8권4호
    • /
    • pp.211-214
    • /
    • 2005
  • CFRD (콘크리트 표면 차수벽형 석괴댐)에서 수행한 전기비저항 탐사 결과, 하부에서 매우 낮은 비저항대가 관측되었다. 일반적으로 CFRD 형식의 댐은 내부 포화가 발생하지 않는 것으로 알려져 있으나, 금번 조사에서 하부 20m 깊이에서 일정하게 저비저항대가 발견되어 이에 대한 검토를 위해 3차원 해석을 수행하였다. 탐사 당시의 수위는 댐 정상부에서 10 m 정도 내려가 있는 상태였다. 첫 탐사 이후 6개월이 지난 후에 이루어진 탐사에서도 비슷한 양상을 보이고 있었다. 이에 대한 해석을 위해서 조사 댐의 모양을 대상으로 3차원 순산 모델링을 수행하고, 이에 대한 2차원 역산 해석을 적용하여 기존 해석 방법의 오류 가능성을 검토하였다. 또한 비저항 조사가 많이 적용된 중심코아형 댐의 경우의 사례와 비교하였다. 해석 결과, 3차원 댐체 구조에 대한 2차원 역산 해석은 저수부의 수위와 밀접한 관련을 갖는 것으로 보이며, 3차원의 사다리꼴 기하구조로 인하여 댐 내부에 비저항의 이상대가 존재할 경우에도 그 민감도가 떨어지는 것으로 분석되었다.

  • PDF

슬랩법을 이용한 쌍롤식 박판주조 공정의 열간 압연 해석 (An Analysis of Hot-Rolling in the Twin-Roll Strip Casting Process by using the Slab Method)

  • 심현보
    • 소성∙가공
    • /
    • 제3권1호
    • /
    • pp.63-83
    • /
    • 1994
  • In this paper, the slab method have been applied to investigate the strip casting process in which hot coil is produced from molten steel directly. In the twin roll strip casting process, molten steel supplied by the nozzle cools and solidifies due to the heat extraction effect of the rolls and hot rolling of the solidified shell takes place simultaneously. The analysis of hot rolling has been carried out by using the existing results of solidification analysis for the twin roll strip casting process. The current slab method provides basic design data such as roll separation force, rolling torque, rolling power as well as end dam separation force which are required to design strip caster. The effect of friction on the basic process parameters are investigated also. It is shown that the use of appropriate friction coefficient is important and that the characteristics of hot rolling in the twin-roll strip casting process is quite different from the conventional hot rolling processes.

  • PDF

턴디쉬용 마그네시아질 댐블록의 제조와 그특성 (characteristics of Magnesia Dam Block for Tundish Vessel in Steel Making Process)

  • 정두화;김상모;이석근
    • 한국세라믹학회지
    • /
    • 제36권8호
    • /
    • pp.876-885
    • /
    • 1999
  • In order to develop high performance basic dam block for tundish vessel in steel-making binders and additives on hydration and thermal characteristics of magnesiz castable refractories were studied. Crack initiation and propagation in cement bonded magnesia castables due to slaking of magnesia clinker at drying process were suppressed by using spinel clinker instead of magnesia powder. In case of Na2O$.$2CaO$.$P2O5(NC2P) bonded castable crack initiation due to slaking of magnesia clinker did not occur but bending strength at high temperature was low. Mechanical properties of NC2P bonded castable refractories at high temperature were improved by using magnesia clinker that contains low SiO2 contents.

  • PDF

An experimental study on tailings deposition characteristics and variation of tailings dam saturation line

  • Wang, Guangjin;Tian, Sen;Hu, Bin;Kong, Xiangyun;Chen, Jie
    • Geomechanics and Engineering
    • /
    • 제23권1호
    • /
    • pp.85-92
    • /
    • 2020
  • This study adopted soil test and laboratory physical model experiments to simulate the tailings impoundment accumulation process according to the principle of similarity. Relying on the practical engineering, it analyzed the tailings deposition characteristics on dry beach surface during the damming process, as well as the variation rules of dam saturation line. Results suggested that, the tailings particles gradually became finer along the dry beach surface to inside the impoundment. The particle size suddenly changed at the junction between the deposited beach and the water surface, which displayed an obvious coarsening phenomenon. Besides, the deposited beach exhibited the vertical feature of coarse upward and fine downward on the whole. Additionally, in the physical model, the saturation line elevated with the increase in dam height, and its amplitude was relatively obvious within the range of 1.0-4.5 m away from the initial dam. Under flood condition, the saturation line height was higher than that under normal condition on the whole, with the maximum height difference of 4 cm. This study could provide an important theoretical basis for further studies on dam failure experiments and the evolution rules of leaked tailings flow.

차수벽에 균열이 발생한 표면차수벽형사력댐의 침투거동 연구 (Study on Seepage Behavior of Concrete Faced Gravel-Fill Dam with Cracked Face Slab)

  • 조성은;박한규;임은상;김기영
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 2009년도 춘계 학술발표회
    • /
    • pp.866-873
    • /
    • 2009
  • CFRD (Concrete Faced Rockfill Dam) has been world-widely constructed due to a lot of advantages compared with rockfill dam and recently, sand/gravel materials, instead of crushed rock materials, are also utilized as a main rockfill material to overcome geological and environmental problems. In this paper, the process of water infiltration into the originally unsaturated sand/gravel-fill dam is studied using two-dimensional saturated-unsaturated seepage theory. According to the results of seepage analysis, if the effective drainage zone is installed in the dam, the reservoir water infiltrate into the dam along a downward flow path towards the lower drainage area. The main body constructed with sand/gravel materials, therefore, remains unsaturated.

  • PDF

필댐 안전관리를 위한 계측기 중요도의 평가기법 (Evaluation Technique of Importance of Monitoring Systems for Earth and Rockfill Dam Safety)

  • 이종욱;김재홍;오병현
    • 한국지반공학회:학술대회논문집
    • /
    • 한국지반공학회 2009년도 춘계 학술발표회
    • /
    • pp.874-882
    • /
    • 2009
  • Continuous monitoring of dam performance is essential to earth and rockfill dams safety because it has to be guaranteed for safety during construction period of course and from initial impounding to a long term maintenance period of dam. Among the 31 dams managed by Kwater at present, the proportion of dams being over 20 years after completion of construction is 42% and it is estimated that the loss rate of monitoring devices will be increase as times. Monitoring devices would be impossible to repair since those are mostly installed in the dam body and foundation. If repairing of monitoring devices is possible, the expenditure will be expensive. Therefore reasonable decision making for abandonment, repair and alternation for loss of monitoring devices would be needed through the establishment of key instrument for earth and rockfill dam safety. In this study the process of monitoring for safety were modeled by failure modes of dams, adverse conditions related to failure mode, indicators of adverse condition and monitoring devices The relationship between failure mode and monitoring devices were systematically analyzed and established and evaluation technique for qualifying the importance of monitoring devices were presented.

  • PDF

모래 공급과 인공 홍수가 양양댐 하류하천의 부착조류에 미치는 영향 (Effects of Sand Supply and Artificial Floods on Periphyton in the Downstream of a Dam (Yangyang Dam, Korea))

  • 박미숙;이재용;정성민;박창근;장군;김범철
    • 한국물환경학회지
    • /
    • 제28권3호
    • /
    • pp.418-425
    • /
    • 2012
  • Dam construction in a river can change its hydrological pattern and trap sediments, which results in ecological changes in the downstream. It is a common phenomenon in the downstream of dams to have decreased sediment flow and increased periphyton. Artificial floods and sediment application are suggested as mitigation practices in order to simulate natural process of flood; transporting sediment and sloughing periphyton off. In this study the effects of artificial floods on periphyton were examined by applying sand artificially and discharging water from a dam (Yangyang Dam, Korea). The study area has been suffering from turbidity problems caused by shore erosion of the dam. The accumulation of inorganic sediments and increase of periphyton on the river bottom are the major factors of habitat deterioration in the downstream reaches. Artificial flood and artificial addition of sand was performed in summer and the effects were measured. Piles of applied sands were washed off easily by discharge and it enhanced the periphyton sloughing effect. The removal efficiency of periphyton was 50 ~ 80% within the 2 km reach from the dam. In conclusion artificial floods and sand application can be a good mitigation measure for the habitat rehabilitation after a dam construction in streams.