• Title/Summary/Keyword: 이정식

Search Result 1,441, Processing Time 0.024 seconds

The Engineering Properties of Shear Strength of Rock Joints in Korea (국내에 분포하는 주요 암석의 절리면 전단강도에 대한 공학적 성질)

  • 김대복;이상근;이정인
    • Journal of the Korean Geotechnical Society
    • /
    • v.17 no.4
    • /
    • pp.301-315
    • /
    • 2001
  • 본 연구에서는 최근 5년간 국내 각 지역에서 채취한 802개의 절리면 시료에 대하여 전단시험을 실시하여 얻은 결과를 이용하여, 절리면의 여러 공학적 성질들을 조사, 연구하였다. 절리면 전단시험에서 얻어진 최대마찰각 및 잔류마찰각을 지체구조별, 암종별로 분류하고 통계적으로 구하였으며, Barton의 전단강도식의 입력변수인 JRC, JCS를 측정하고 Barton식의 적용성에 대해서도 검토하였다. 그 결과 설계의 기초자료로 활용할 수 있는 지역별, 주요 암종별 최대마찰각, 잔류마찰각을 제시하였다. 또한, JRC, JCS, 수직응력에 따른 마찰각과 전단강성 및 팽창각의 변화를 분석하였다. 마지막으로, Barton의 식에서 구한 이론적 전단강도와 이 실험에서 얻어진 전단강도를 비교한 결과, Barton의 경험식은 높은 상관도로 암석 절리면 전단강도를 예측할 수 있음을 확인하였다.

  • PDF

Minimum Velocity of Sewerage Pipes (하수관거의 최저유속)

  • Yu, Dong-Hun;Lee, Jeong-Yeong
    • Journal of Korea Water Resources Association
    • /
    • v.32 no.4
    • /
    • pp.469-478
    • /
    • 1999
  • Explicit equations of minimum velocity, energy slope and pipe diameter are developed to ensure the cleaning of sewerage pipes. The equations of power form are employed for the estimation of critical shear stress of sediment particles and the friction factor of commercial pipes. They are all based on the existing laboratory data. Several cases are tested to check the values suggested in the manual, using the equations developed in the present study.

  • PDF

Estimation of Continuous Infiltration Process by Unsaturated Permeability (불포화투수계수를 이용한 지반의 연속 침투능 산정)

  • Han, Heui-Soo;Lee, Jung-Sik;Jang, Jin-Uk;Yang, Nam-Young
    • The Journal of Engineering Geology
    • /
    • v.20 no.2
    • /
    • pp.137-146
    • /
    • 2010
  • To estimate the accumulated infiltration, Horton's and Green-Ampt's equations are usually applied. Because the real infiltration is penetrated into the soil continuously, to cover the problems of the conventional equations derived from the discontinuous infiltration system, new infiltration equation is derived from the concepts of continuous infiltration system. Furthermore, infiltration tests were done to compare the results from the conventional Horton's and Green-Ampt's equations and newly derived equation. Unsaturated permeability is the function of water content ratio or saturation degree, which affects directly to the infiltration capacity and accumulated infiltration. Therefore, the variation term of unsaturated permeability is inserted into the new equation to estimate the proper infiltration capacity and accumulated infiltration. It will make the more accurate analysis for the safety of structure and the behavior of groundwater.

An Experimental Study for Local Scour of the Riverbed at Pier (교각주변(橋脚周邊) 하상(河床)의 국부세굴(局部洗掘)에 관한 실험적(實驗的) 연구(硏究))

  • Lee, Won Hwan;Lee, Jung Sik;Lee, Hong Rae
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.5 no.1
    • /
    • pp.65-74
    • /
    • 1985
  • This study is an experimental analysis for local scour of the riverbed at pier. The basic equation with dimensionless elements(Pier Reynolds Number, Dimensionless Turbulence Intensity) is derived through dimensional analysis. After testing the goodness of fit of data, the coefficients are determined by multiple regression analysis. In the region where the value of the attack angle is near 20 degrees, there exists a transition region where the slope of equation with Pier Reynolds Number changes from positive to negative and that of equation with Dimensionless Turbulence Intensity changes from negative to positive adversely. As a result of testing the equation suggested on this study by using the data of the Institute of National Construction, it is found that the scour depth and width at pier can be predicted approximately.

  • PDF

Morphology and Histochemical Characteristics of the Alimentary Tract in Surfperch, Ditrema temmincki (망상어, Ditrema temmincki 소화관(消化管)의 형태(形態).조직화학적(組織化學的) 특징(特徵))

  • Lee, Jung-Sick;Chin, Pyung
    • Korean Journal of Ichthyology
    • /
    • v.7 no.2
    • /
    • pp.140-149
    • /
    • 1995
  • Morphology and histochemical characteristics of the alimentary tract in surfperch, Ditrema temmincki were investigated by histological observation. The relative length of gut(RLG) in surfperch, that is the postpharyngeal portion of the alimentary tract, is about 0.89 to standard length. The absence of a stomach, which is the part of expantion of the alimentary tract between esophageal end and the entrance of the bile duct into the intestine, was observed. The alimentary tract is divided into the esophagus, esophageal-intestine part, anterior intestine, mid intestine, posterior intestine, intestinorectum part, rectum, rectal-anus part, and anus by morphology and histochemical features. Morphology of mucosal folds is the most complexity in the rectum and the tunica muscularis of the esophagus and anus is more advanced than those of other parts. The epithelial layers of mucosal folds consist of columnar epithelium except for cuboidal cells of the anterior part of the esophagus. The goblet cells and polysaccharide absorptive cells were observed in the alimentary tract. Nutritive polysaccharide is mainly absorbed by the absorptive cells in the posterior intestine of the surfperch.

  • PDF

Development of Relational Formula between Groundwater Pumping Rate and Streamflow Depletion (지하수 양수량과 하천수 감소량간 상관관계식 개발)

  • Kim, Nam Won;Lee, Jeongwoo;Lee, Jung Eun;Won, You Seung
    • Journal of Korea Water Resources Association
    • /
    • v.45 no.12
    • /
    • pp.1243-1258
    • /
    • 2012
  • The objective of this study is to develop the relational formula to estimate the streamflow depletion due to groundwater pumping near stream, which has been statistically derived by using the simulated data. The integrated surface water and groundwater model, SWAT-MODFLOW was applied to the Sinduncheon and Juksancheon watersheds to obtain the streamflow depletion data under various pumping conditions. Through the multiple regression analyses for the simulated streamflow depletion data, the relational formula between the streamflow depletion rate and various factors such as pumping rate, distance between well and stream, hydraulic properties in/near stream, amount of rainfall was obtained. The derived relational formula is easy to apply for assessing the effects of groundwater pumping on near stream, and is expected to be a tool for estimate the streamflow contribution to the pumped water.