• 한국농공학회지
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• 제16권3호
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• pp.3477-3491
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• 1974

Following are the results of the study on the property of falling permeation of stratified soil in the close state under existence of stagnant water on a soil layer. 1. When on the stratified soil a least permeating layer was put on the soil layer the load Pressure was present owing to appearance of saturation close state driving decrease of the pressure in the lower layer, on the other hand when the least permeating layer was placed under the layer the lower least permeating layer pressure was decreased. 2. In the case of least permeating layer the variation of current gradient according to the respective level after treating the layer was enormous and due to usal storage phenomena for the Kl layer which was coarse that was trifle. 3. The permeability of the respective layer of stratified soil in the close state died not always coincide with that of single layer. 4. Generally Zunker's equation of average permeability was valid but actually calculated permeating velocity after treating the layer of stratified soil was seriously differ from the measured value owing to the variation of current gradient, especially when the pressure head at the layer boundany was discontinuous the validity of the equation of average permeability was seemed to be doubtful. 5. The permeating velocity of stratified soil was regulated by the least permeating layer, i.e. it is thought to be rational to estimate the value by calculating the current gradient with its proper permeability, pressure headon the layer and its thickness.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1999년도 정기총회 및 춘계 공동 학술발표회
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• pp.74-74
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• 1999

• 한국수자원학회논문집
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• 제30권6호
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• pp.699-708
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• 1997

3차원 추계학적 방법을 사용하여 성층화된 흙에서 유효 비포화투수계수를 유도하였다. 성층화된 흙의 상관길이는 차이가 있기 때문에 추계학식이 단순화되면서 유효 비포화투수계수에 대한 일반식을 해석적으로 유도할 수 있게 된다. 또한 평균흐름이 특정한 범위(습윤전선, 젖음과정, 마름과정)에서 유효한 단순화된 점근식을 유도하였다. 예증으로 이론적인 결과를 가상 점토에 적용하였다. 그 결과 유효 비포화투수계수는 거시적인 이력현상을 나타냄을 알 수 있었다. 거시적인 이력현상이란 미시적인 미력현상이라기 보다는 오히려 흙의 공간적인 변동으로 인하여 발생하는 것이다. 또한 유효 비포와투수계수는 흙의 비균질성을 무시한 경우보다 비균질성을 고려한 경우에서 크게 나타났다.

• Journal of Ginseng Research
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• 제21권2호
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• pp.115-118
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• 1997

Stratified American ginseng(Panax quinquefoilium L.) seeds were planted in a shaded greenhouse at four depths and in four different soil types to observe effects on emergence rate and root size. Seeding depth affected seedling emergence rates and the number of days required to complete emergence. The shape of the roots was affected by the texture of soil, especially percentage of sand.

• Coupled systems mechanics
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• 제5권3호
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• pp.203-221
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• 2016

The present study deals with the numerical modelling for the one dimensional contaminant transport through saturated homogeneous and stratified porous media using meshfree method. A numerical algorithm based on element free Galerkin method is developed. A one dimensional form of the advectivediffusive transport equation for homogeneous and stratified soil is considered for the analysis using irregular nodes. A Fortran program is developed to obtain numerical solution and the results are validated with the available results in the literature. A detailed parametric study is conducted to examine the effect of certain key parameters. Effect of change of dispersion, velocity, porosity, distribution coefficient and thickness of layer is studied on the concentration of the contaminant.

• Structural Engineering and Mechanics
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• 제24권2호
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• pp.213-225
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• 2006

The propagation of non-uniformly modulated, evolutionary random waves in viscoelastic, transversely isotropic, stratified materials is investigated. The theory is developed in the context of a multi-layered soil medium overlying bedrock, where the material properties of the bedrock are considered to be much stiffer than those of the soil and the power spectral density of the random excitation is assumed to be known at the bedrock. The governing differential equations are first derived in the frequency/wave-number domain so that the displacement response of the ground may be computed. The eigen-solution expansion method is then used to solve for the responses of the layers. This utilizes the precise integration method, in combination with the extended Wittrick-Williams algorithm, to obtain all the eigen-solutions of the ordinary differential equation. The recently developed pseudo-excitation method for structural random vibration is then used to determine the solution of the layered soil responses.

• Interaction and multiscale mechanics
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• 제1권1호
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• pp.157-175
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• 2008

A brief review of the research works on ground vibrations caused by trains moving in underground tunnels is first given. Then, the finite/infinite element approach for simulating the soil-tunnel interaction system with semi-infinite domain is summarized. The tunnel is assumed to be embedded in a homogeneous half-space or stratified soil medium. The train moving underground is modeled as an infinite harmonic line load. Factors considered in the parametric studies include the soil stratum depth, damping ratio and shear modulus of the soil with or without tunnel, and the thickness of the tunnel lining. As far as ground vibration is concerned, the existence of a concrete tunnel may somewhat compensate for the loss due to excavation of the tunnel. For a soil stratum resting on a bedrock, the resonance peak and frequency of the ground vibrations caused by the underground load can be rather accurately predicted by ignoring the existence of the tunnel. Other important findings drawn from the parametric studies are given in the conclusion.

• 한국농공학회지
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• 제15권1호
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• pp.2913-2924
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• 1973

이와같은 방법(方法)에 의(依)하여 얻은 몇가지 시험결과(試驗結果)를 요약(要約)하면 다음과 같다. 1. 어느 시험구(試驗區)를 막론(莫論)하고 건조진행(乾燥進行)은 표층토(表層土)가 라지구(裸地區)보다는 초지구(草地區)가 그 진행속도(進行速度)가 좀빠른 경향(傾向)을 나타냈다. 2. 건조과정(乾燥過程)에 강우(降雨)가 있으며 토양수분(土壤水分)은 강우침투경로(降雨浸透經路)를 통(通)하여 포장용수량(圃場容水量) 또는 수분당량(水分當量) 부근(附近)으로 회복(回復)하고 있다. 3. 성층토양(成層土壤)에서 하층토(下層土)의 토성(土性)이 상층토(上層土)의 건조(乾燥)에 미치는 영향(影響)은 다음과 같이 설명(說明)된다. 가. 하층토(下層土)가 S이고 토층토(土層土)가 CL 또는 SL인 경우에 이 CL 또는 SL의 건조(乾燥)는 포장용수량(圃場容水量)이 적은 하층(下層)의 S가 어느정도(程度) 모관수공급(毛管水供給)의 차단층(遮斷層)이 되어 하층토(下層土)가 SL 또는 CL로 되었을 때보다 훨씬 건조(乾燥)가 빨리 진행(進行)하며 CL보다는 SL쪽이 현저(顯著)하게 빨리 건조(乾燥)한다. 나. 하층토(下層土)가 SL이고 상층토(上層土)가 S 또는 SL인경우에 이 S 또는 CL의 건조(乾燥)는 포장용수량(圃場容水量)이 비교적(比較的) 크고 또 모관수전도도(毛管水傳導度)도 비교적(比較的) 원활(圓滑)한 하층(下層)의 SL로 인(因)하여 그 진행속도(進行速度)가 가장 완만하며 S보다는 CL쪽이 더빨리 건조(乾燥)하는 경향(傾向)이다. 다. 하층토(下層土)가 CL이고 상층토(上層土)가 S 또는 SL인 경우에 이 S 또는 SL의 건조(乾燥)는 포장용수량(圃場容水量)이 가장 크나 모관수전도도(毛管水傳導度)가 가장느린 하층(下層)의 CL로 인(因)하여 그 진행속도(進行速度)가 비교적(比較的) 빠른 편(便)이며 S보다는 SL쪽이 더 발리 건조(乾燥)하는 경향(傾向)이다. 4. 상층토양(上層土壤) 및 하층토양(下層土壤)에서의 함수비(含水比)에 대(對)한 1일간(日間)의 시간적(時間的) 변화(變化)를 보면 상층토양(上層土壤)이 CL 및 SL에 있어서는 기온(氣溫)이 상승(上昇)하는 $12{\sim}15$시(時) 사이 까지는 함수비(含水比)가 감소(減少)되고 18시(時) 이후(以後)부터는 약간(若干) 회복(回復)하는 경향(傾向)을 보이는데 이에 반(反)하여 S에 있어서는 기온(氣溫)이 상승(上昇)하는 $12{\sim}15$시(時)에 함수비(含水比)가 Peak점(點)을 이루는 경향(傾向)을 보였으며 하층토양(下層土壤)에서의 함수비(含水比)는 CL, SL 및 S모두 기온상승(氣溫上昇)에 따라서 약간감소(若干減少)하는 경향(傾向)을 나타냈고 구름낀날의 함수비(含水比)의 변화(變化)는 CL, SL 및 S공(共)히 맑은 날에 비(比)하여 약간(若干) 작은 경향(傾向)을 보였다. 5. 적산계기증발량(積算計蒸發量)에 대(對)한 적산토양수분소비율(積算土壤水分消費率)은 일반적(一般的)으로 화지구(華地區)가 라지구(裸地區)보다 큰 경향(傾向)을 보였으며 시일(時日)의 경과(經過)에 따라 그 율(率)이 감소(減少)하는 경향(傾向)을 보였고 또 그것은 초기(初期)에는 주(主)로 상층토양(上層土壤)의 토성(土性)에 좌우(左右)되고 후기(後期)에는 하층토양(下層土壤)의 토성(土性)에 많이 좌우(左右)되는 경향(傾向)이었다. 6. 적산토양수분소비율(積算土壤水分消費率)은 하층토(下層土)가 SL 또는 S이고 상층토(上層土)가 CL인 경우(境遇)에 하층(下層)이 SL인 경우(境遇)가 S인 경우보다 변화폭(變化幅)에 컸으며, 하층(下層)이 CL, 또는 S이고 상층(上層)이 SL인 경우(境遇)는 가장 큰 값을 나타냈는데 하층(下層)이 CL인 소우(塑遇)의 그 값은 S인 경우보다 약간(若干)큰 경향(傾向)을 보였다. 또한 하층(下層)이 CL 또는 SL이고 상층(上層)이 S인 경우는 위에 말한 두 경우보다도 작은 값을 보였으며 하층(下層)이 CL인 경우(境遇)가 SL인 경우보다 더욱더 작은 값을 나타내는 경향(傾向)을 보였으며, 즉(卽) 본시험(本試驗)에서의 토양수분(土壤水分) 소비율(消費率)은 대체(大體)로 SL/CC> SL/S>CL/SL> CL/S$\fallingdotseq$S/SL> S/CL>의 순위(順位)로 되었다.

• Journal of Forest and Environmental Science
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• 제34권1호
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• pp.12-23
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• 2018

Quantitative information on biomass and available nutrients are essential for developing sustainable forest management strategies to regulate atmospheric carbon. An attempt was made at Chilapatta Reserve Forest in Duars region of West Bengal to quantify its above and below ground carbon along with available "N", "P" and "K" in the soil. Stratified random nested quadrats were marked for soil, biomass and litter sampling. Indirect or non-destructive procedures were employed for biomass estimation. The amount of these available nutrients and organic carbon quantified in soil indicates that the forest soil is high in organic carbon and available "K" and medium in phosphorus and nitrogen. The biomass, soil carbon and total carbon (soil C＋C in plant biomass) in the forest was 1,995.98, 75.83 and $973.65Mg\;ha^{-1}$. More than 90% of the carbon accumulated in the forest was contributed by the trees. The annual litter production of the forest was $5.37Mg\;ha^{-1}$. Carbon accumulation is intricately linked with site quality factors. The estimated biomass of $1,995.98Mg{\cdot}ha^{-1}$ clearly indicates this. The site quality factor i.e. tropical moist deciduous with optimum availability of soil nutrients, heavy precipitation, high mean monthly relative humidity and optimum temperature range supported luxuriant growth which was realized as higher biomass accumulation and hence higher carbon accumulated.

• 한국환경복원기술학회지
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• 제4권1호
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• pp.16-23
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• 2001

This study was conducted to analyse the relation between physical characteristics of soil surface and wild plants occurrence. Lots of natural occurrence on loamy soil and a little of natural occurrence on perlite. Those were used to observe the wild plants occurrence through the duration. Natural occurrence of wild plants were observed on uniform sand, perlite, loamy soil and 2cms loamy soil layer above the perlite. Uniform sand was compared with different height of drain ditch. The results of analysis were as followed. 1. Wild plants germinated on the uniform perlite layer, they did not grow larger. Because water in large pores of perlite surface drained rapidly and evaporated easily, therefore surface remained low moisture contents. 2. A lot of weed grew on 2cms loamy layer on perlite which stratified above the perlite layer. Because perlite had plenty of soil moisture and soil moisture moved easily from perlite to loamy soil layer. 3. Uniform loamy soil had similar occurrence on the uniform perlite. It was nearly same at surface moisture distribution but lower than layered loamy soil on perlite, and the vertical distributions at soil moisture was totally lower than 2cms loamy soil layer on perlite. 4. Wild plants were grew on uniform sand on different height of drain ditch. In this case, much more wild plants were grew on which had more higher drainage ditch. The number of wild plants occurred when it was affected by soil surface moisture, drain ditch and natural occurrence of wild plants. This could be controlled by layered soil at surface moisture. Therefore weed occurrence can control in planting ground, where soil layer would not be disturbed.