• 한국농림기상학회지
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• 제1권1호
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• pp.29-35
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• 1999

본 연구는 경기도 광주지역의 낙엽송 임분에 인공 강우기를 설치하여 수리특성과 관련한 공간 변이와 상관관계를 구명하기 위하여 수행되었다. 수분유속과 보유능은 원래 토성, 구조와 유기물을 근거로 지표면에서 인공가우기로 수분을 일정속도로 가하면서 측정하였다. 이 방법은 간단히 유기물을 제거하거나 기존의 상태에서 수평한 지표면에 3가지의 강우 강도에서 실시하였으며 한편 경계면은 안정하며 포화상태의 습윤 토양에서 투수계수와 매트릭 유속기능을 조사하였다. 투수계수는 $_1$( $Z_{c}$) = $_2$( $Z_{c}$) = $_{c}$ 이라는 지속적 유속 조건하에서 $K_{i+}$$_1$ $_{c}$= $K_{i}$( $_{c}$) [1-d /dz]의 공식을 적용하였다. 본 연구 결과 토양내에서 유속에 영향을 미치는 공극 특성과 유기물 함량이 광범위하게 수분 보유능과 포화투수계수의 공간 변이에 영향을 미치는 것으로 조사되었다.것으로 조사되었다.되었다.

• 한국토양비료학회지
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• 제44권5호
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• pp.722-726
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• 2011

The management standard on soil conditions in 'Fuji' apple to produce high quality fruit were not yet made. Therefore, this study was carried out to investigate the optimum soil environmental conditions of ten contents on production of high quality fruit in 'Fuji' apple. The soil and fruit characteristics were analyzed at total 60 orchards in major apple producing areas such as Chungju, Moonkyeung, yeongju, andong, yeosan and yeongcheon (10 orchards an area). The soil environmental factors affected fruit weight was highest relative contribution in saturated hydraulic conductivity of 36.5%. The bulk density and soil pH were low as relative contribution. The fruit weight was influenced by soil physical properties more than soil chemical properties. The soil environmental factors affected sugar content were hydraulic conductivity of 28.3% and organic matter content of 18.2%. The cultivation layer depth and soil pH were low as relative contribution. The fruit coloring was highest relative contribution in saturated hydraulic conductivity 55.9%. while soil pH, cation and soil texture were low. Fruit coloring was high influenced over 70% by soil physical properties. Finally, relative contribution on fruit quality related with sugar content, fruit weight, and coloring were high influenced by saturated hydraulic conductivity of 21.% and organic matter content of 18.7% but bulk density and cultivation layer depth were low relative contribution. The fruit growth and saturated hydraulic conductivity in 'Fuji' apple were very closely related. Therefore, orchard soil management to produce high quality fruit was very importance drainage management and organic matter application. We concluded that scientific soil management is possible by qualifiable of soil management factors.

• 대한환경공학회지
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• 제28권6호
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• pp.626-633
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• 2006

본 연구는 부천시를 대상으로 지하수의 함양량, 대수층의 수리학적인 특성, 심도 및 지하수 심도에 따른 수리, 화학적 특성, 지하수의 오염특성을 파악하기 위해 수행되었다. 수리시험의 대상공은 부천지역의 토지이용형태와 도시발달을 고려하여 충적층 2개 지점과 암반층 9개 지점, 총 11개 지점을 선정하여 양수시험과 함께 회복시험을 동시에 실시하였다. 대수층의 투수량계수, 수리전도도 등의 수리상수를 도출하기 위해 양수시험은 충적층은 Theis의 해법에 의해 해석하였으며 암반층은 Theis의 회복해법에 의해 해석하였다. 학교운동장, 녹지공간이 확보된 공원 지역내 양수정은 지하수량이 다른 지역보다 풍부하고, 투수량계수와 수리전도도가 높은 값을 보였는테 이 지역이 강수의 수직침투와 수평이동이 활발하여 도시지역에서 주요 지하수 함양지역임을 뒷받침한다. 도심권의 도로 및 건축물에 의해 포장된 지역 양수정에서는 수리상수 값이 낮아 지하수의 함앙이 어려운 지역으로 관찰되었다. 부천지역 48개 지점에서 채수한 지하수는 심층기반암이 화성암에 기인하여 지하수가 약산성화된 특성을 보였다. 부천시의 지역별 전기전도도는 $70.4{\sim}1,287{\mu}S/cm$의 범위를 보였으며 용해성 광물이나 일부 탄산염의 영향을 받아 대부분의 지역에서 다소 높게 검출되었다.

• 한국정밀공학회지
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• 제33권2호
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• pp.139-147
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• 2016

Performances of urethane packing in the hydraulic breaker were analyzed using a finite element method. Because of high temperature and high pressure in the hydraulic breaker, it is better to use urethane rather than rubber as a packing material. We obtained the physical properties of urethane at elevated temperature by the tensile test. We analyzed buffer seal and U-packing maintaining the pressure and preventing oil leakage. Deformation, stress distribution, contact length, contact pressure of packing at each pressure step were obtained using finite element analysis. As the temperature increases, stress and contact force tend to decrease at low pressure. As the gap between piston and cylinder increases, contact length and contact forces decrease. Consequently, it is possible to design the packing section using these analyses, and construct a system to predict the possibility of oil leakage in the hydraulic breaker.

• Environmental Engineering Research
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• 제18권3호
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• pp.129-137
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• 2013

The infiltration of rainwater into the surface soil is highly dependent on hydraulic variables, such as the infiltration rate, capillary fringe, moisture content, and unsaturated/saturated hydraulic conductivity. This study estimates the hydraulic conductivity (K) of fluvial deposits at three sites on the right and left banks of Nakdong River in Gyeongbuk Province, South Korea, including the Gumi, Waegwan, and Seongju bridge sites. The K values of 80 samples from 13 boreholes were estimated by using six grain-size methods (Hazen, Slichter, Kozeny, Beyer, Sauerbrei, and Pavchich formulae). The Beyer, Hazen, and Slichter methods showed a better relationship with K values along with an effective grain size than did the other three methods. The grain-size, pumping test, and slug test analyses resulted in different K values, but with similar K values in the grain-size analysis and pumping test. The lower K values of the slug test represent the uppermost fine sand layer.

• 보존과학회지
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• 제34권4호
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• pp.295-303
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• 2018

The application of reinforcing agents with hydraulic property and strength development characteristics was studied under conditions similar to those of mural-painting mortar made with oyster shell powder. Reinforcement mortar made with oyster shell powder showed hydraulic properties and strength to supplement the weaknesses of natural hydraulic lime(NHL); this confirmed its possibility as a wall-reinforcing material with enough strength for preserving mural paintings. Reinforcement mortar 1 showed hydraulic property and general characteristics of lime mortar, such as consistency and viscosity, as well as lower strength and higher whiteness compared to an NHL product. For Reinforcement mortar 2, the original wall sample characteristics were reflected by mixing more shell produced through calcination; and it showed similar strength to that of Reinforcement mortar 1 as well as high whiteness. In measuring the contraction ratio of reinforcement mortar samples, Reinforcement mortar 1 and 2 showed more stability in property change compared to the NHL Group.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.272-280
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• 2003

A definite shut-in pressure in hydraulic fracturing techniques is needed for obtaining the correct information on the in-situ stress regimes in rock masses. The relation between the behaviour of hydraulically induced fractures and the condition of remote stress is considered to be major reasons of an ambiguous shut-in pressure in hydraulic fracturing pressure-time history curves. This paper describes the results of a series of numerical analyses carried out using UDEC(Universal Distinct Element Code, Itasca), which is based on the discrete element method, to compare several methods for determining the shut-in pressure during hydraulic fracturing. The fully coupling of hydraulic and mechanical analysis was applied, and the effects of four different discontinuity geometries in numerical modelling have been investigated for this purpose. The effects of different remote stress regimes and different physical properties on hydraulic fracture propagation have been also analyzed. Several methods for obtaining shut-in pressure from the ambiguous shut-in curves have been applied to all the numerical models. The graphical intersection methods, such as (P vs. t) method, (P vs. log(t)) method, (log(P) vs. log(t)) method, give smaller values of the shut-in pressure than the statistical method, (dP/dt vs. P). Care should be taken in selecting a method for shut-in pressure, because there can be existed a stress anomaly around the wellbore and fracturing from the wellbore by a constant flow rate may have a more complicate mechanism.

• 한국지반공학회논문집
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• 제21권3호
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• pp.119-131
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• 2005

댐 안정성 평가를 위하여 불포화 이론을 이용한 침투해석 기법이 널리 사용되고 있으나 지반의 불포화 거동에 대한 인식 부족과 실험절차의 번거로움으로 인하여 입력 물성치에 대한 체계적인 실험과 평가가 일반화되지 못하고 있는 실정이다. 불포화 수리특성에 따라 침투수량 및 간극수압 분포 등 댐체 및 제방의 침투거동이 달라지나 국내 지반에 대한 실험자료 부족으로 대부분 단순 추정에 의한 값을 사용하고 있다 본 연구에서는 불포화 수리특성이 댐체의 침투 거동에 미치는 영향을 살펴보기 위하여 함수특성곡선과 투수계수곡선에 대하여 고찰하고 수치해석을 수행하였다. 해석결과 변수 a와 n은 값이 클수록, m은 값이 작을수록 중력에 의한 침윤선의 하강이 빨리 발생하였다. 유한차분 형식에 의해 개략적으로 계산한 민감도는 침윤선 부근에서 가장 크게 나타났고 시간에 따른 민감도의 변화에는 함수특성곡선의 기울기와 관련된 n값이 가장 큰 영향을 주었다.

• 터널과지하공간
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• 제21권2호
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• pp.117-127
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• 2011

균열암반의 역학적 및 수리적 성질에 암반 초기응력이 미치는 영향을 고찰하였다. 지질 데이터는 스웨덴 원전원료 및 방사성 폐기물 관리회사(SKB)에 의해 수행된 포쉬마크지역의 부지조사로부터 획득되었으며 암반균열망-개별요소법 수치실험(Discrete Fracture Network - Discrete Element Method) 을 통하여 암반의 등가역학적 및 등가수리적 물성을 결정하였다. 수치실험결과 균열 강성의 응력의존성, 균열 방향에 따른 상이한 변형거동, 균열거동에 따른 수리유동 경로의 변화 등의 원인에 의하여 등가역학적 및 등가수리적 물성은 응력의존성이 큰 것을 확인하였다. 본 연구의 결과는 암반 초기응력의 정확한 예측이 특정 부지에서의 경계조건으로서뿐만 아니라 균열암반의 역학적 및 수리적 물성을 이해하는 데도 중요한 역할을 한다는 것을 보여준다.

• 한국토양비료학회지
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• 제48권5호
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• pp.522-527
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• 2015

Decision of available soil depth based on soil physical and hydraulic properties for the $3^{rd}$ Landscape Vegetation Project in the Incheon International Airport was attempted. The soil samples were collected from the 8 sites at different depths, 0-20 and 20-60cm, for the three project fields, A, B, and C area. Physical and chemical properties including particle size distribution, organic matter content and electrical conductivity were analyzed. Hydrological properties including bulk density and water holding capacity at different water potential, -6 kPa, -10 kPa, -33 kPa, and -1500 kPa were calculated by SPAW model of Saxton and Rawls (2006), and air entry value was calculated by Campbell model (1985). Based on physical and hydrological limitation, feasibility and design criteria of soil depth for vegetation and landfill were recommended. Since the soil salinity of the soil in area A area was $19.18dS\;m^{-1}$ in top soil and $22.27dS\;m^{-1}$ in deep soil, respectively, landscape vegetation without amendment would not be possible on this area. Available soil depth required for vegetation was 2.51 m that would secure root zone water holding capacity, capillary fringe, and porosity. Available soil depth required for landscape vegetation of the B area soil was 1.51 m including capillary fringe 0.14 m and available depth for 10% porosity 1.35 m. The soils in this area were feasible for landscape vegetation. The soil in area C was feasible for bottom fill purpose only due to low water holding capacity.