• 한국산림과학회지
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• 제56권1호
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• pp.66-76
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• 1982

사방시공지(砂防施工地)에 널리 조림(造林)되는 리기다소나무의 근계분포(根系分布)와 토양(土壤)의 견밀도(堅密度)의 관계(関係)를 구명(究明)하고자 표본지(標本地)를 선정(選定) 대표목(代表木)의 경사하측(傾斜下側)에 환상(環状)의 토양단면(土壤斷面)을 만들어 각토층별(各土層別)로 토양경도(土壤硬度)를 산중식(山中式) Soil hardness tester로 측정(測定)하고 수근(樹根) (중세근(中細根))의 분포(分布)를 조사(調査)하여 분포(分布)한바 다음과 같이 요약(要約)할 수 있었다. 1) 토양(土壤)의 견밀도(堅密度)는 토심(土深)이 깊어짐에 따라 점차(漸次) 증가(增加)하여 평균(平均) 지표경도(指標硬度)는 I층(層)에서 14.6mm II층(層)에서 16.2mm, III층(層) 17.2mm, IV층(層)에서는 18.3mm, V층(層)에서는 19.8mm였다. 2) 수근(樹根) (중세근(中細根))은 표층(表層)에 이를수록 많이 분포(分布)하여 토층(土層)이 깊어짐에 따라 그 수(數)가 감소(減少)하여 I층(層) 수근(樹根)의 수(數)를 1(31%)로 할때 II층(層)은 0.84(26%), III층(層)은 0.6(18%), IV층(層)은 0.4(12%), V층(層)도 0.4(13%)이다. 3) 토양(土壤)의 견밀도(堅密度)와 수근(樹根)의 분포(分布)는 음(陰)의 상관관계(相関関係)에 있어 견밀도(堅密度)가 높아지면 이에따라 수근(樹根) 수(數)는 감소(減少)한다. 각(各) 토층별(土層別) 토양(土壤)의 견밀도(堅密度)와 수근분포(樹根分布)의 상관계수(相関係数)는 I층(層)은 -0.3875, II층(層)은 -0.5299, III층(層)은 -0.5573, IV층(層)은 -0.6922, V층(層)은 -0.7325, 전체평균(全体平均)은 -0.9469로서 모두 유의적(有意的)이었다. 4) 리기다소나무의 수근(樹根) (중세근(中細根))의 성장(成長)에 최적합(最適合)한 토양(土壤)의 견밀도(堅密度)는 지표경도(指標硬度)는 12.0~14.9mm로서 이 계급(階級)에 속(屬)하는 지표경도(指標硬度)는 33%이고 수근(樹根)의 분포(分布)는 41.8%이다. 또 지표경도(指標硬度) 20.9mm까지는 82%이나 수근(樹根) 93.2%가 분포(分布)하고 있어 지표경도(指標硬度) 20.9mm이하(以下)까지가 리기다소나무의 수근(樹根)의 생장(生長)에 적합(適合)하다고 사료(思料)된다.

• 한국작물학회지
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• 제44권1호
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• pp.20-25
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• 1999

This experiment was conducted to elucidate the relation-ship between vertical distribution of rice roots and yield traits under field conditions. Eight IRRI's new plant type rices (NPTRs) were tested in a volcanic ash soil paddy field under dense (IO 10 cm) and common (20 20 cm) planting densities. These lines were evaluated to have more spikelet numbers per panicle (SNP), lower filled grain rate (FGR), and lower rough grain weight per hill (RGWH). In dense planting, rough grain weight per stem (RGWS) was increased due to heavier culm and leaf dry weight (CLDW), and both RGWS and CLDW were related with the percentage of root distribution (%RWI) in the 10~30 cm soil layer, while in common planting, RGWS was not closely related with CLDW. SNP was highly related with root dry weight (RDW) in the 0~10cm soil layer. FGR was mainly affected by ROW in the 10~30 cm soil layer under both planting densities. RGWS was positively correlated with top dry weight (TDW) and harvest index (HI), and TDW was positively correlated with RWI under common planting or %RWI under dense planting, and HI was positively correlated with RWI in the 10~30 cm soil layer only under dense planting. RGWS was closely related with root weight index by dry weight (RWI) in the 10~30 cm soil layer and %RWI in the 0~30 cm or 10~30 cm soil layer under dense planting, and with only RWI in the 10~30 cm soil layer under common planting. But RGWH showed the close positive relationship with RDW and RWI in the 10~30 cm soil layer under dense planting, while under common planting, it showed the close positive relationship with RWI and %RWI in the 10~30 cm soil layer or %RWI in the 0~30 cm soil layer. The deeper root system in rice, especially under dense planting, is important for high yield of NPTRs focusing on the increment of top mass production and harvest index.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 지반공학 공동 학술발표회
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• pp.510-516
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• 2005

This research aims to verify the stress distribution in soil according to the composition of the soil layer in case of surface loading. For this purpose, loading tests with measurement of stresses in the soil on four kinds of layered model ground in laboratory were performed. Those are (1)homogeneous sand, (2)gravel underlain by sand, (3)sand underlain by clay and (4)gravel underlain by clay. Test results are compared and analysed for the compositions of the soil layers. based on the results obtained, it is found that the larger the difference of the strengths of upper and lower layer is, the smaller the stress in the soil in case of surface loading is.

• 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.

• Earthquakes and Structures
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• 제12권2호
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• pp.153-163
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• 2017

The underlying goal of the present paper is to investigate soil and structural uncertainties on impedance functions and structural response of soil-shallow foundation-structure (SSFS) system using Monte Carlo simulations. The impedance functions of a rigid massless circular foundation resting on the surface of a random soil layer underlain by a homogeneous half-space are obtained using 1-D wave propagation in cones with reflection and refraction occurring at the layer-basement interface and free surface. Firstly, two distribution functions (lognormal and gamma) were used to generate random numbers of soil parameters (layer's thickness and shear wave velocity) for both horizontal and rocking modes of vibration with coefficients of variation ranging between 5 and 20%, for each distribution and each parameter. Secondly, the influence of uncertainties of soil parameters (layer's thickness, and shear wave velocity), as well as structural parameters (height of the superstructure, and radius of the foundation) on the response of the coupled system using lognormal distribution was investigated. This study illustrated that uncertainties on soil and structure properties, especially shear wave velocity and thickness of the layer, height of the structure and the foundation radius significantly affect the impedance functions, and in same time the response of the coupled system.

• The Korean Journal of Ecology
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• 제13권1호
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• pp.25-32
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• 1990

The vertical distribution and seasonal fluctuation of soil microarthropods in the forests with different flora were investigated in this study. soil micrarthropods were concentrated as much as 71.8% in the first layer subsoil (0-5cm), 22.3% in the second layer subsoil (5-10cm), and 5.9% in the third layer subsoil (10-15cm) in the decreasing order. The population density in the first layer decreased slightly in winter while that of the second layer increased. However, the density in the first layer bounced back in the following spring. Seasonal fluctuations of population density were revealed "Two peak-Two valley type", that is, the densities were high in fall and spring, and low in winter and summer.nd summer.

• 지질공학
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• 제17권4호
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• pp.665-671
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• 2007

본 연구에서는 독도 동도지역의 토질에 대한 공학적 특성을 조사하고, 산사태발생 가능성을 조사하였다. 이를 위하여 먼저 독도의 동도지역에 대한 토층분포 및 심도를 조사하고, 토질특성을 조사하기 위하여 시료를 채취하였다. 현장조사 결과 동도지역의 토층은 일부구간에 부분적으로 분포해 있으며, 토층의 심도는 $1{\sim}50cm$로 존재하고 있음을 알 수 있다. 토층의 심도는 대부분 구간에서 10cm내외로 존재하고 있다. 토질은 모암의 오랜 풍화로 인하여 생성된 풍화잔류토층으로서 썩은 나무뿌리 혹은 나뭇잎과 같은 유기물 성분이 매우 많이 함유되어 있음을 알 수 있다. 토질의 함수비는 평균 23.2%, 액성한계는 평균 42.2%이며, 비소성(non-plastic)인 것으로 나타났다. 그리고 대부분 입도분포가 불량한 모래로 분류할 수 있으며, 일부 롬(loam)이 함유되어 있음을 알 수 있다. 한편, 대상지역에 대한 토층의 발달양상을 파악하여 독도 동도지역의 산사태 발생가능성을 조사하였다. 대부분의 구간에서 토층의 심도가 매우 얕고 토층의 분포지역이 넓지 않은 것으로 나타났다. 따라서 산사태가 발생할 수 있는 조건을 만족하지 못하므로 산사태 발생가능성은 매우 낮은 것으로 예측할 수 있다.

• 한국습지학회지
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• 제22권4호
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• pp.328-336
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• 2020

본 연구에서는 국내 피트층의 토양특성(입지환경)을 분석하여 충남 태안군의 신규 피트 분포지역을 예측하고 피트층의 특성을 비교하였다. 국내에서는 충남 태안, 경기 평택, 강원 강릉, 울산, 전북 익산 및 전남 장흥 등에서 피트층에 대한 연구가 진행되었으며, 이 연구 지역들의 피트층 토양에 대한 분포지형, 퇴적양식, 배수등급 및 토양아목의 특성을 통해 입지환경을 분석하고 피트 분포 예측기준을 선정하였다. 충남 태안군의 사례연구를 통해 피트층 분포 지역은 두 가지 형태로 확인되었다. 첫 번째로는 곡간지, 충적붕적층, 배수 약간불량 및 aqualfs 특성을 보이는 지역과, 두 번째로는 해성평탄지, 충적층, 배수 매우불량 및 aquepts 지역들이었다. 실제 피트층의 분포 확인을 위해 현장 탐침조사를 수행하였으며, 신규 피트층과 기존 연구 결과를 비교한 결과 국내의 피트 발견지역은 모두 해안선에서 10 km 이내에 위치하며, pH 5, 휴믹산 15% 이내의 성분으로 구성된 dark brown 계열 색상의 피트로 확인되었다. 또한 신규 피트층은 타지역에 비해 깊이는 깊고 두께는 두꺼우나 분해도는 상대적으로 낮은 것으로 나타났다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.423-428
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• 2005

If the load of constructing vehicles during the construction work acts on the road or the ground surface on the soft ground, due to the excess stresses in soils the trafficability of the vehicles influences the constructing efficiency, constructing period and so on. Stress distribution in soils is the very important element to design and to solve the problems of settlement, safety of foundations and trafficability of constructing vehicle in civil engineering. This research represents the comparative estimation of the actual and theoretical measurement on the underground stress of outer layer for each soil after the observation of each top soil layer for its vertical and horizontal stress in (1)homogeneous sand ground (2) weak stratum with the sand soil (3) weak stratum with gravel of the soil model, and it also investigates the effect of subsidence of ground by the repeated load. The underground stress turn out to be different in the value of theoretical and actual measurement after the trial examination of model.

• Geomechanics and Engineering
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• 제29권1호
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• pp.91-97
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• 2022

The cohesive non-swelling soil (CNS) cushion technology has been widely applied in the subgrade and slope improvement at expansive soil regions. However, the mechanism of the inhibition effect of the CNS layer on expansive soil (ES) has not been fully understood. We performed four outdoor model tests to further understand the inhibition effect, including different kinds of upper layer and thickness, under the unidirectional seepage condition. The swelling deformation, soil pressure, and electrical resistivity were constantly monitored during the saturation process. It is found that when a CNS layer covered the ES layer, the swelling deformation and electrical resistivity of the ES layer decreased significantly, especially the upper part. The inhibition effect of the CNS layer increases with the increase of CNS thickness. The distribution of vertical and lateral soil pressure also changed with the covering of a CNS layer. The electrical resistivity can be an effective index to describe the swelling deformation of ES layer and analyze the inhibition effect of the CNS layer. Overall, the CNS deadweight and the ion migration are the major factors that inhibit the swelling deformation of expansive soil.