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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of The Korean Society of Civil Engineers
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Journal DOI :
Korean Society of Civil Engeneers
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Volume & Issues
Volume 17, Issue 3_6 - Nov 1997
Volume 17, Issue 2_6 - Nov 1997
Volume 17, Issue 1_6 - Nov 1997
Volume 17, Issue 3_5 - Sep 1997
Volume 17, Issue 2_5 - Sep 1997
Volume 17, Issue 1_5 - Sep 1997
Volume 17, Issue 3_4 - Jul 1997
Volume 17, Issue 2_4 - Jul 1997
Volume 17, Issue 1_4 - Jul 1997
Volume 17, Issue 3_3 - May 1997
Volume 17, Issue 2_3 - May 1997
Volume 17, Issue 1_3 - May 1997
Volume 17, Issue 3_2 - Mar 1997
Volume 17, Issue 2_2 - Mar 1997
Volume 17, Issue 1_2 - Mar 1997
Volume 17, Issue 3_1 - Jan 1997
Volume 17, Issue 2_1 - Jan 1997
Volume 17, Issue 1_1 - Jan 1997
Selecting the target year
Anisotropy Ratio of Effective Hydraulic Conductivity in Stratified Soil using Stochastic Approach
Yun, Soung-Yong ; SonU, Jung-Ho ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 411~411
The anisotropy ratio of effective unsaturated hydraulic conductivities in stratified soils is evaluated using a three-dimensional stochastic approach. Simple asymptotic expressions, valid at particular ranges (wetting front, wetting condition, drying condition) of the soil property and the mean flow characteristics, are used. Examples for the theoretical results applicable to two real soils are presented. It was found that the anisotropy ratio of effective unsaturated hydraulic conductivities show large-scale hysteresis which is produced by the spatial variability of soil properties. The results suggested a clear difference in the trend of anisotropy ratio of effective unsaturated hydraulic conductivities between two types of flow conditions, the wetting and the drying ones and that the anisotropy ratio of effective unsaturated hydraulic conductivities are the function of soil property and capillary pressure. The field observations are in qualitative agreement with the predictions of the stochastic theory for anisotropy ratio of effective unsaturated hydraulic conductivities in case of wetting condition. This paper was to present the stochastic modeling methodology without focusing on specific evaluation and application. In order to be useful in stochastic theory should be further developed in cases of practical interest.
Unsaturated Flow Experiment in Heterogeneous Anisotropic Media
Park, Jae-Hyeon ; Yun, Soung-Yong ; SonU, Jung-Ho ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 421~421
The results of the laboratory experiment in the unsaturated heterogeneous anisotropic media are presented, and the Yun's model(1994), which analyzed the unsaturated heterogeneous anisotropic media using the stochastic modeling, is verified by the experimental results. The experimental apparatus consists of a sand box and an instrument of supplying a constant flux. For forming the heterogeneous anisotropic media sample the silty, the fine, and the coarse sands were in-situ sampled and compounded in the laboratory under the hypothesis based on the full-stratification According to the experiment, the unsaturated horizontal flow is much more dominant than the vertical flow as the capillary pressure and heterogeneity are larger. These results are in accord with the conclusion drawn from the Yun's wetting condition model.
A Comparative Analysis of Rainfall-Runoff Models Applied to a Residential Site
Heo, Jun-Haeng ; Seo, Kyu-Woo ; Lee, Hong-Lae ; Lee, Jae-Cheol ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 429~429
In this study, Chungju Yongam Residential Site basin (99.7 ha) was selected in an effort to analyze the changes in runoff characteristics due to large scale residential development. A hydrological observation system was operated for the effects of urbanization on runoff and hydrological patterns were analyzed using several urban runoff models such as CHICAGO, RRL, ILLUDAS, and SWMM. The parameters for each model were calibrated and verified aganist the observation data (June 27 and July 15 of 1996). The tested models were proved to be well applied through the comparative analysis of runoff simulations in urban watershed.
Friction Factor of Smooth Turbulent Flow in Rectangular Open Channel
Yoo, Dong-Hoon ; Lee, Jong-Won ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 441~441
It is found from the laboratory data of Varwick (1945) that the open channel flow has five characteristic flow regions like the flow in pipe but the distribution of friction factor moves up parallel as the roughness becomes bigger. Based on these facts, Bazin's (1865) data are considered to be mostly in smooth turbulent condition, and the equivalent roughness height is determined by conducting laboratory experiments. The friction factor equation of rectangular open channel flow is developed by modifying Prandtl-von Karman equation used for the smooth turbulent pipe flow. In the previous study the modification was made by relating one of two parameters to the roughness height, but in the present study by relating both parameters to the roughness height, of which the non-dimensional number is the ratio of Reynolds number to Weber number. The modified equation is again tested against Bazin's laboratory data and the data collected in the present study.
A Study on the Pre-release Effects of the Reservoir Operation during the Flood Seasons
Hwang, Man-Ha ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 453~453
In practice, the reservoirs must be operated for not only water supply but also flood control. With this point of view, this study is to estimate the pre-release effects of the reservoir operation during the flood seasons. The method of pre-release is as follows : 1) A storage for flood control is put to the use for water supply, 2) The storage for water supply is rent for the flood control when a flood is expected., 3) The penalty related with water supply is levied when the initial storage is not recovered after a flood. In this paper, this algorithm is applied to the flood events on Soyang reservoir using the weather forecasting data. That result shows that the method is useful to attain the reservoir storage for water supply, to reduces the flood damages which of the magnitude depends on the accuracy of forecasted rainfall.
Mitigation in Reclamation Area of Saemangeum by Tidal Residual Flow
Shin, Moon-Seup ; Yanagi, Tetsuo ; Kweon, Cheol-Hooi ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 461~461
The purpose of this study is to find the method by which minimize the anti-function of development in the coastal region. The changes of tide and tidal residual flow before and after the construction of dike and submerged breakwater in reclamation area of Saemangeum are calculated using a two-dimensional numerical model. We compared the tide and tidal current before and after the construction of submerged breakwater, to investigate the possibility of MITIGATION in the fisheries. The numerical results coincide well with field observations.
Numerical Modeling of Coastal Watertable
Kang, Hong-Yoon ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 469~469
A one-dimensional time-dependent numerical model is presented for predicting coastal watertable movement using the Boussinesq equation. A reflecting, no flux boundary condition at the landward boundary is assumed, whereas the measured glassy/dry boundary (G/D) moving with time corresponding to a beach watertable exit point and the mean water surface shoreline (MWSS) which always sits lower than G/D are used as the seaward boundary condition, respectively. The model results with the measured G/D boundary condition slightly overestimate the watertables measured on a natural beach, but those with the measured MWSS boundary condition slightly underestimate the Held data. This suggests that the seaward boundary location should be somewhere between the mean water surface shoreline and the glassy/dry boundary.
Nonlinear Interaction between the Permeable Submerged Breakwater and the Second Order Stokes Waves by Weakly Nonlinear Model
Kim, Do-Sam ; Yun, Duk-Yong ; Hur, Dong-Soo ; Ham, Gye-Un ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 477~477
Recently, the interests of the construction of the submerged breakwater have been increased to preserve and to improve the coastal environment, and to control the incident waves and littoral transport. It is important to predict the wave transformation due to the permeable submerged breakwater. The wide submerged breakwater and the shallow water depth on its crown are needed, generally, to break the incident waves and to decrease the wave energy by friction between the rubble stones and the waves, because its transport is very much on the crown. In this case, the amount of rubble stones of the permeable submerged breakwater is greatly increased, which results in the increment of construction cost. In this study, the one-rowed and two-rowed submerged breakwaters are considered, where the rubble stones of the two-rowed one are smaller than those of the one-rowed one. The objective of this study is to discuss the nonlinear wave transformation and its characteristics of each breakwater type. Dupuit-Forchheimer formula is applied to the in analysis of the the fluid resistance of rubble stones, and the equation about equivalent linear frictional parameter is modified based on the Lorentz's condition for the equivalent work. The frequency domain method, based on the pertubation method and the boundary element method (BEM), is used for the analysis of nonlinear wave transformation. The numerical results are compared with the experimental and Kio-ka's ones for the verification of this study. It seems to be in the good agreements among the three results. It might be confirmed that the two-rowed submerged breakwater can control the incident waves more efficiently than the one-rowed one.
Application of Ultrafiltration Process for Municipal Wastewater Reuse
Song, Kyung-Guen ; Ahn, Kyu-Hong ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 493~493
This experiment investigates the applicability of ultrafiltration (UF) for reuse of municipal wastewater. The data generated from this experiment are intended to be used as a guideline in actual operation. No modification in the design of the conventional biological treatment process is assumed, and the suitability of the wastewater after treatment by ultrafiltration for reuse such as toilet-flush or cleaning is evaluated. The experiment was conducted by varying crossflow velocity and cross-membrane pressure, and monitoring the respective changes in the cross-membrane flux and effluent quality. It was found that at steady-state, cross-membrane flux increased proportionally with crossflow velocity, but not with cross-membrane pressure. Maximum cross-membrane flux per unit cross-membrane pressure was observed at
(98 kPa). It was observed that the higher the cross-membrane pressure, the more variance in the effluent quality. Therefore, it was concluded that the optimum cross-membrane pressure in actual operation must be decided after the consideration of the resulting cross-membrane flux and range of variance in effluent quality.
Evaluation of Pilot Filter for the Control of Coagulation Process
Han, Moo-Young ; Byoun, Suk-Ho ; Kang, Chang-Ho ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 503~503
The purpose of this study is to evaluate the applicability of pilot filter as a method of controlling coagulation process from laboratory and field experiment and to give operational guideline when it is used in water treatment plants. In a laboratory experiment, the response of pilot filter was observed according to the variation of coagulation parameter such as raw water turbidity, pH and coagulant dosage. In a Held experiment (full scale test), the response of pilot filter was observed in an operating water treatment plant where coagulant dosage was intentionally changed step by step. The operational parameter and the result of pilot filter was compared and analyzed. From the results of both laboratory and field experiment, pilot filter is found to be useful as a coagulation control method together with the existing jar test method in water treatment plants.
Biotransformation Pathway of 2,4,6-Trinitrotoluene (TNT) under Aerobic Conditions by a Pure Soil Bacteria
Bae, Bum-Han ;
Journal of The Korean Society of Civil Engineers, volume 17, issue 2_5, 1997, Pages 513~513
Experiments were performed to assess the capability of a soil microorganism, Enterobacter sp., for the mineralization of TNT in a respirometer with
labeled TNT. Enterobacter sp. mineralized 3.2% of the TNT within 10 days of incubation and highly polar intermediates accumulated in the reactor medium. The distribution of
activity showed that 3.2% evolved as
, 13.5% in the biomass, and 80.7% remained in the liquid phase. The result was reproducible. The unknown polar intermediates were extracted and identified by GC/MSD. These compounds were identified to be 4-acetamido-2, 6-dinitrotoluene, 4-acetamido-2-amino-6-nitrotoluene, 4-amino-2-nitrotoluene, and 4-acetamido-2-nitrotoluene. In addition, 3-methyl catechol (3MC), a precursor of benzene ring cleavage, was identified. Results showed that the transformation of TNT by Enterobacter sp. included reduction, denitration, and acetylation reaction. The biotransformation of TNT into 3MC is the first to be reported and its presence verifies the potential for aerobic mineralization of TNT. However, the formation or acetylated compounds is being considered as a dead-end judging from the accumulation of these compounds. Therefore, transformation of TNT with Enterobacter sp. should be further studied to understand the mechanisms and enzyme systems involved in TNT transformation.