방조제 축조에 따른 침하량 연구(Ⅳ)

장병욱 서울대학교 농업개발연구소 2000 농업생명과학연구 Vol.4 No.-

When a sea-dike is constructed on soft soils, loss by running flow, replacement by quarry and consolidation settlement of clay ground must be made clear to estimate the amount of quarry accurately. Because the study on the ground deformation is incomplete, most of design does not slough off existing practice. In this study, development of ground deformation analysis system, development of consolidation settlement analysis system for soft ground and development of measuring management and analysis system under a sea-dike constructed on soft soils were performed. In the fourth year study, development of settlement section estimation system, program, and development of mesh generator pre-processor and pre-processor program were performed.

畓에서의 有效雨量에 關한 硏究

金成俊,朴承禹,張秉郁,權純國,鄭夏禹 서울大學校 農科大學 1986 서울대농학연구지 Vol.11 No.1

In this study, a daily water balance model for effective rainfall in paddy fields is descrived, and compares the results with field data. The model was used to simulate seasonal effective rainfall for ideal plots with different irrigation scheduling. The followings are a summary of this study results: 1. Effective rainfall during irrigation season of paddy fields in 1985 ranged from 172.3mm at 4cm ridge to 206.7mm at 6cm ridge. They were 63.1% and 75.7% of total precipitation during that span, respectively. The water balance model simulated that 60.5% and 69.5% precipitation may be considered to be effective rainfall. 2. Daily rainfall appears to be important to the ratios of effective rainfall to the total. 3. Measured and estimated effective rainfall had a high correlation. R=0.9805

시멘틱 공유를 위한 MDA기반 지하공간정보 온톨로지 모델 개발

이상훈(Lee Sang Hoon),장병욱(Chang Pyoung Wuck) 대한공간정보학회 2009 대한공간정보학회지 Vol.17 No.1

최근 이질적인 정보의 폭발적인 증가와 다양한 관리주체별로 생산, 축적되는 공간정보의 특성으로 인하여 공간정보의 재사용과 공유가 어려운 실정이다. 국가공간정보체계의 하나인 지하공간정보도 공간분석을 위해서는 지형도, 지질도, 지하시설물도 등 여타 공간정보와 공유가 필수적이다. 그러나, 기존 표준 혹은 데이터웨어하우스에 의한 공유방법은 시멘틱 이질성을 고려할 수 없다. 본 연구는 지하공간정보의 시멘틱 공유를 위해 일반개념, 측정스케일, 공간모델을 포함한 온톨로지 레이어 모델을 개발하였다. 또한, 기존의 수작업에 의존하는 온톨로지 개발방법론이 아닌 MDA기반 방법론을 적용하여 직관적이며 환경변화에 쉽게 대응할 수 있는 메타모델(UML Profile)을 개발하였다. 개발된 온톨로지 모델의 시멘틱 품질은 Pellet 추론엔진을 통해 검증하였다. 본 연구를 통해 시멘틱 공유를 증진시키고, 온톨로지의 지식표현 능력을 이용하여 GIS 전문가시스템 개발이 가능할 것으로 기대된다. Today, it is difficult to re-use and share spatial information, because of the explosive growth of heterogeneous information and specific characters of spatial information accumulated by diverse local agency. A spatial analysis of subsurface spatial informa-tion, one of the National Spatial Data Infrastructure, needs related spatial information such as, topographical map, geologic map, underground facility map, etc. However, current methods using standard format or spatial datawarehouse cannot consider a se-mantic hetergenity. In this paper, the layered ontology model which consists of generic concept, measuremnt scale, spatial model, and subsurface spatial information has developed. Also, the current ontology building method pertained to human experts is a expensive and time-consuming process. We have developed the MDA-based metamodel(UML Profile) of ontology that can be a easy under-standing and flexiblity of environment change. The semantic quality of devleoped ontology model has evaluated by reasoning engine, Pellet. We expect to improve a semantic sharing, and strengthen capacities for developing GIS experts system using knowledge representation ability of ontology.

불포화 점성토의 체적변화에 대한 연구

장병욱 ( Chang Pyoung Wuck ),길상춘 ( Gil Sang Choon ) 한국농공학회 1998 韓國農工學會誌 : 전원과 자원 Vol.40 No.5

This study was performed to evaluate the characteristics of volume change is unsaturated clayed soil. The medium-plastic clay was selected and compacted by 50% of Proctor standard compaction energy at 6% higher moisture content than its OMC. A series of isotropic compression tests and triaxial shear tests were performed. The results of the study are summarized as follows. At each matric suction, when the matric suction was increased, the yield stress was increased and slope of volume change was decreased. The more net mean stress was, the less the quantity of volume change was. In shear test, the volumetric strain was much rapidly changed in large matric than in low matric suctions. But the effect of matric suction to volume change disappeared under high net mean stress. At lower deviator stress the more matric suction was, the higher volume change was. But As the matric suction was increasing, the behavior of the unsaturated clayey soil was similar to that of saturated clayey soil. Volume change in the unsaturated clayey soil can be represented as a unique plane in three-dimensional space, which is the axes of net mean stress, matric suction and void ratio.

Fall cone과 수화열을 이용한 흙-시멘트 혼합물의 상 변화 연구

김재형,원정윤,김성필,장병욱,Kim Jae-Hyung,Won Jeong-Yun,Kim Sung-Pil,Chang Pyoung-Wuck 한국지반공학회 2004 한국지반공학회논문집 Vol.20 No.9

고함수비 상태의 흙에 시멘트를 첨가하게 되면 흙의 공학적 성질을 개량할 수 있다. 이렇게 고함수비 흙에 시멘트를 혼합하는 경우 흙시멘트 혼합물의 워커빌러티와 밀접한 관련이 있는 상 변화를 예측하고 구분하는 것은 매우 힘들다. 시간에 따른 시멘트 paste의 수화열 변화와 경도의 변화는 흙시멘트 혼합물의 상 변화에 대한 유용한 정보를 제공해준다. 본 연구에서는 시멘트 paste와 흙/시멘트 비를 달리 한 3 종류의 혼합물에 대해 수화열과 콘 관입량을 측정하여 흙시멘트 혼합물의 상 변화를 관찰하였다. 실험결과, 흙시멘트 혼합물의 상 변화는 시멘트 paste와 동일한 형태를 보이며 수화열이 최소가 되는 시점에서 혼합물의 전단강도가 급격하게 증가함을 알 수 있었다. 흙시멘트 혼합물의 초결시점은 fall cone 관입량이 1.0mm, 즉 혼합물이 소성상태에 도달하는 시점과 일치하며 흙/시멘트 비가 증가할수록 초결시간은 지연되었다. 흙시멘트 혼합물에 대한 수화열 측정과 fall cone 관입량 측정은 흙-시멘트 혼합물의 상 변화를 예측하는 유용한 수단으로 사용할 수 있다. Some amount of cements can be added into the soil with high water content to improve the engineering properties. In such a case, it is difficult to predict and figure out the phase changes of the soil-cement mixture which is closely associated with workability of the soil-cement mixture. Changes in heat of hydration and hardness of the cement pastes are known to provide the useful information about the phase changes of the soil-cement mixtures. In this study, heat of hydration and cone penetration depth were measured from the specimens of cement paste and 3 soil-cement mixtures. From the experimental results, it was found that the phase changes of the soil-cement mixtures are the same as those of cement paste, and that shear strength of the mixtures abruptly increases when the heat of hydration is minimum. Initial setting time of the mixtures coincides with the state when fall cone penetration depth was 1.0 mm and it is defined as plastic limit of the mixtures. Initial setting time of the mixtures is retarded as soil/cement ratio is increased. Measurements of heat of hydration and fall cone apparatus could be the useful tools to predict the phase changes of tile soil-cement mixtures.

석질토(碩質土)의 배수삼축압축시험(排水三軸壓縮試驗)에서의 강도특성(强度特性)

장병욱 ( Chang Pyoung Wuck ),송창섭 ( Song Chang Seob ) 한국농공학회 1992 韓國農工學會誌 : 전원과 자원 Vol.34 No.3

The shear strength of cohesionless soils results from particle-to-particle friction and struc-tural resistance by interlocking. And, the shear Strength of soils is subjected to vary depending on the internal states and external condtions. If the volume Change occurring in the soils and stress- strain relationships under the internal and external changes can accrurately be described, it is possible to predict the behaviors of soils. To accomplish these objectives a series of drained triaxial compression tests and isotropic compression test was performed on the Banwol sand at different relative densities ranging from 20% to 80% and different confining pressures ranging from 0.4kgf/cm² to 1.2kgf/cm². The results and main conclusions of the study are summarized as follows : 1. When the relative density or the confining pressure is increased, the maximum deviator stress is increased. The ratio of the maximum deviator stress and confining pressure is linearly proportional to the relative density. 2. It is observed that the dilatancy depends not only upon its relative density but also the confining stress, and that the maximum deviator stress is obtained after the diatancy occurs. 3. The volume of sands undergoes initial contraction prior to the dilatancy occurred by strain softening. The dilatancy rate eventually approaches the critical state or constant volume. 4. At lower strains, Poisson’s ratio approaches a certain minimum value regadless of the state of materials. At larger strains, however the ratio is increased as the relative density is increased. 5. It is observed that the modulus of elasticity is linearly proportional to the relative density and the pressure. 6. When the relative density is increased, the friction angle of sands is linearly increased. 7. When the relative density is increased, the expansion index and the compression index are linearly decreased, and the ratio of the two is about 1/3.

앵커의 극한(極限) 지지력(支持力) 변화(變化)와 파괴(破壞) 거동(擧動)에 관한 연구(硏究)

장병욱 ( Chang Pyoung Wuck ),황명수 ( Hwang Myung Soo ) 한국농공학회 1990 韓國農工學會誌 : 전원과 자원 Vol.32 No.4

Model tests for the ultimate pullout resistance of anchorages and investigation of failure behaviors in cohesionless soil have been conducted. The factors affecting the anchorage are mostly the geometry of the system, and soil properties of sands. The main conclusions of the experimental work were as follows. 1. The load - displacement relationship can be a form of parabolic curve for all plates. 2. The change in ultimate pullout resistance of anchor is mostly affected by embedment ratio and size of anchor, and influenced to a lesser degree by its shape. 3. Critical embedment ratio which is defined as the failure mode changes from shallow to deep mode is increased with increasing height of anchor. 4. For a constant anchor height, as the width of anchor increases the ultimate pullout resistance also increases. However, considering the efficiency of anchor for unit area, width of anchor does not appear to have any sigrnificant contribution on increasing anchor city. 5. Anchor capacity has a linear relation to sand density for any given section and the rate of change increases as the section increases. Critical depth determining the failure patterns of anchor is decreased with a decrease of sand density. 6. With increasing inclination angle, size of anchor, and decreasing embedment ratio, the ultimate pullout resistance of anchor under inclined loading is significantly decreased. 7. The ultimate pullout resistance of double anchor, a method of improving single of anchor capacity, is influenced by the center - to - center spacing adjacent anchors. It is also found that tandem and parallel anchor rigging arrangements decrease the anchor system capacity to less than twice the single anchor capacity due to anchor interference.

불포화 정성토의 체적변화에 대한 연구

장병욱,길상춘,Chang, Pyoung-Wuck,Gil, Sang-Choon 한국농공학회 1998 韓國農工學會誌 : 전원과 자원 Vol.40 No.5

This study was performed to evaluate the characteristics of volume change is unsaturated clayed soil. The medium-plastic clay was selected and compacted by 50% of Proctor standard compaction energy at 6% higher moisture content than its OMC. A series of isotropic compression tests and triaxial shear tests were performed. The results of the study are summarized as follows. At each matric suction, when the matric suction was increased, the yield stress was increased and slope of volume change was decreased. The more net mean stress was, the less the quantity of volume change was. In shear test, the volumetric strain was much rapidly changed in large matric than in low matric suctions. But the effect of matric suction to volume change disappeared under high net mean stress. At lower deviator stress the more matric suction was, the higher volume change was. But As the matric suction was increasing, the behavior of the unsaturated clayey soil was similar to that of saturated clayey soil. Volume change in the unsaturated clayey soil can be represented as a unique plane in three-dimensional space, which is the axes of net mean stress, matric suction and void ratio.

바닥사석충의 통수에 따른 성토제체 침윤선 변화 연구

이행우 ( Lee Haeng-woo ),장병욱 ( Chang Pyoung-wuck ),장웅희 ( Chang Woong-hee ),정인영 ( Chung In-young ) 한국농공학회 2004 한국농공학회 학술대회초록집 Vol.2004 No.-

본 연구는 방조제에서 바닥사석충의 유·무 및 성토충의 길이에 따라 성토충의 침투특성에 미치는 영향을 파악하기 위하여 수리모형실험을 실시하였으며, 아울러 흐름상태가 다른 바닥사석충의 흐름을 정확히 해석하는가를 알아보고자 수치해석으로 성토충의 침윤선을 계산하여 실측치와 비교분석하였다. 본 연구의 결론은 다음과 같다. 1) 성토충에서 측정한 수두와 수치해석으로 계산한 수두가 차이를 보였으며, 이는 바닥사석충의 흐름특성이 흙속의 흐름과는 상이한 것으로 판단된다. 2) 바닥사석충의 유·무에 따라서 성토충의 침투특성이 크게 차이가 났으며 또한 바닥사석충의 길이에 따라서 방조제 침투안정에 영향을 미치는 것으로 나타났다. 3) 향후 연구를 위한 제안으로 방조제의 실제에 부합하는 침윤선 계산 및 침투안정해석을 위하여 바닥사석충의 흐름특성 및 수두손실에 대한 연구가 필요함. One of the major role of the sea dike is protecting farmlands from the storm surges and tidal wave attacks. Furthermore, sea dike makes a bit easier to reclaim the landside of the sea dike and supplies water to the farmland and factory. Although water in the landside of the sea dike is likely to non salt water, it is practically allowed and maintained some extent of salt concentration because of the construction of bottom riprap. Flow in the bottom riprap is an interesting topic to study in order to maintain water with minimum salt concentration in the fresh water. Generally, the change in phreatic line has affected to the overall stability and it may cause a piping and sliding of the sea dike. This paper presents the change in phreatic line through flow in bottom riprap in the sea dike. This study is performed and compared to seepage analysis and prototype hydraulic model test results.

Evaluation of Engineering Properties of Soft Clay in the Daebul Reclaimed Area

( Chang Pyoung Wuck ) 한국농공학회 1995 韓國農工學會誌 : 전원과 자원 Vol.37 No.-

To identify the soft marine clay of the Daebul reclaimed area, the south western part of Korea, and determine their engineering properties, a series of the laboratory and field tests are conducted. The main findings are summarized from laboratory and field investigations. It is also formulated the basic geotechnical characteristic data for the project area. The established correlations for the engineering properties are reviewed and their applicabilities are studied.