• 한국토양비료학회지
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• 제33권6호
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• pp.398-404
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• 2000

본 시험은 높은 비율의 물로 회석된 토양용액의 EC(electrical conductivity)와 saturation parte EC($EC_e$) 간의 상관관계를 검토하고자 실시하였다. 시험토양은 24개 절화장미 재배지에서 수집하였고, 토성은 대부분 양토와 미사질양토 이었으며, 얻어진 시험 결과는 다음과 같다. 토양용액의 총이온 함량과 EC 간에는 고도의 정의 상관관계가 인정되고, 물추출 비율이 증가할수록 토양용액중 이온의 총략은 증가하였으나, 1:1, 1:2, 1:5 비율로 EC를 측정한 다음 각각 1, 2, 5를 곱한 EC 값은 $EC_e$에 비해 현저히 낮은 결과를 보였다. 이는 보다 높은 비율의 물로 추출한 용액의 EC와 $EC_e$간에 큰 오차가 있음을 의미한다. 포화 이상의 물추출조건 하에서 발생하는 이러한 오차를 감소시키기 위하여 회석된 용액의 EC값에 새로온 Diluted factor(DF)와 비선형 등식을 적용하여 $EC_e$를 추정한 결과, 두 방법 모두 측정된 ECe와 추정된$EC_e$간 1차 식의 기울기가 1에 근접하여 새로 적용된 방식들이 기존의 측정방식에 비해 정확성을 높여줄 수 있는 것으로 나타났다. 반면에 DF값은 토성에 크게 의존적이며, 비선형 등식을 이용한 측정방식은 토양의 saturation percentage에 따라 추정된 $EC_e$가 변동되므로 폭넓은 토성에 대한 추가적인 연구가 필요할 것으로 판단된다.

• 아시안잔디학회지
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• 제23권2호
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• pp.271-278
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• 2009

본 연구는 골프장의 상토조성 시 사용되는 토양개량제의 적절한 활용과 이해를 위해 입경과 화학적 특성이 비슷한 무기성 토양개량제의 3종의 혼합비율에 따른 모래상토의 물리 화학적 특성변화를 조사하였다. 토양개량제의 혼합비율에 따라 상토의 물리 화학성을 조사한 결과는 다음과 같다. A와 C가 pH가 95% 수준에서 상관성을 나타내었고, C의 양이온치환용량이 95% 수준에서 상관성을 보여 토양개량제의 특성에 따라 상토의 토양화학성에 영향을 주었다. 상토의 토양물리성 결과를 통해 USGA 기준으로 평가할 때, 최적의 혼합비율은 토양개량제 A와 B에서는 3%였고, C는 7~10% 였다. 각 토양개량제들의 혼합에 따른 토양물리성변화에 가장 큰 영향을 미치는 물리적 요인은 총공극량이었다. 토양개량제의 혼합비율에 따른 토양개선효과 를 비교할 때, B는 모세관공극과 비모세관공극에서, C는 모세관공극, 총공극 및 수리전도 도에서 고도의 상관성을 나타내었다(P<0.05). 이들 결과를 통해 골프코스의 상토조성에 사용되는 무기성 토양개량제는 그 종류와 혼합비율이 USGA 상토의 뿌리층 개량의 토양 이화학성에 영향을 미치고 있음을 알 수 있었다.

• 생명과학회지
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• 제11권2호
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• pp.153-158
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• 2001

To investigate the effects of soil acidification on growth of Impatiens balsamina L. plants were transplanted to acidified soils with H$_2$SO$_4$ solution. The concentrations of soluble Ca, Mg, K, Al and Mn in the acidified soils increased with increment of H$^{+}$ addition to the soil. In both species, the plant height and root length were inhibited by soil acidification, showing much severer inhibition in Impatiens balsamina L. than in Tagetes patula L., As the soil pH decreases, the growth of underground parts decreased greatly than that of above ground parts in both species. Total dry weight decreased with increased Al concentration as well as lowered soil pH in both plants. There was a strong positive correlation between relative total dry weight and molar (Ca+Mg+K) / Al ratio of the soil. The results suggest that molar(Ca+Mg+K)/ Al ratio of the soil may be useful indicator for assessing the critical load of acid deposition in herb species.s.

• Geomechanics and Engineering
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• 제15권1호
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• pp.695-710
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• 2018

Formation of a soil plug in an open-ended pile is a very important factor in determining the pile behavior both during driving and during static loading. The degree of soil plugging can be represented by the incremental filling ratio (IFR) which is defined as the change in the plug length to the change of the pile embedment length. The experimental tests carried out in this research contain 138 tests that are divided as follows: 36 tests for single pile, 36 tests for pile group ($2{\times}1$), 36 tests for pile group ($2{\times}2$) and 30 pile group ($2{\times}3$). All tubular piles were tested using the poorly graded sand from the city of Karbala in Iraq. The sand was prepared at three different densities using a raining technique. Different parameters are considered such as method of installation, relative density, removal of soil plug with respect to length of plug and pile length to diameter ratio. The soil plug is removed using a new device which is manufactured to remove the soil column inside open pipe piles group installed using driving and pressing device. The principle of soil plug removal depends on suction of sand inside the pile. It was concluded that the incremental filling ratio (IFR) is changed with the changing of soil state and method of installation. For driven pipe pile group, the average IFR for piles in loose is 18% and 19.5% for L/D=12 and 15, respectively, while the average of IFR for driven piles in dense sand is 30% and 20% for L/D=12 and L/D=15 respectively. For pressed method of pile installation, the average IFR for group is zero for loose and medium sand and about 5% for dense sand. The group capacity increases with the increase of IFR. For driven pile with length of 450 mm, the average IFR % is about 30.3% in dense sand, 14% in medium and 18.3% for loose sand while when the length of pile is 300 mm, the percentage equals to 20%, 17% and 19.5%, respectively.

• 한국작물학회지
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• 제44권2호
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• pp.102-105
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• 1999

Mineralization of organic N is an important factor in determining the appropriate rate of organic matter application to paddy fields. A kinetic analysis was conducted for nitrogen mineralization of rice, barley, Chinese milk Ovetch (Astragalus sinicus L.; MV) and narrow leaf vetch straw in paddy soil. Nitrogen immobilization occurred rapidly and its rate increased in straw with high C/N ratio. The amount of nitrogen mineralization was rapid in the first year of rice-vetch cropping system. The rate constant (K) depended on the C/N ratio of organic matter. Mineralization of straw increased at high temperature. The amount of available N increment resulted in fast mineralization of straw, especially in rice and barley straw. Chinese milk vetch had the greatest mineralization rate at all temperatures and fertilization levels followed by narrow-leaf vetch. However, rice and barley straws with high C/N ratio immobilized the soil N at the initial incubation duration. Chinese milk vetch or narrow leaf vetch was not effectively mineralized in mixed treatments with rice or barley straw. The mineralization rate of organic matter was mostly affected by the C/N ratio of straw and temperature of incubation. Organic matter with low C/N ratio should be recommended to avoid the immobilization of soil N and the increasing mineralization rate of straw.

• 한국농공학회지
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• 제21권2호
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• pp.81-103
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• 1979

The weathered granite soil involves problems in its stability in soil structures depending upon the reduction of soil strength due to the water absorption, crushability, and content of colored mineral and feldspar. As an attemt to solve the problems associated with soil stability, the crushability of weathered granite soil was investigated by conducting tests such as compaction test, CBR test, unconfined compression test, direct shear test, triaxial compression test, and permeability test on the five soil samples different in weathering and mineral compositions. The experimental results are summarized as follows: The ratio of increasing dry density in the weathered granite soil was high as the compaction energy was low, while it was low as the compaction energy was increased. The unconfined compressive strength. and CBR value were highest in the dry side rather than in the soil with the optimum moisture content, when the soil was compacted by adjusting water content. However, the unconfined compressive strength of smples, which were compacted and oven dried, were highest in the wet side rather than in soil with the optimum moisture content. As the soil becomes coarse grain, the ratio of specific surface area increased due to increased crushability, and the increasing ratio of the specific surface area decreased as the compaction energy was increased. The highest ratio of grain crushability was attained in the wet side rather than in the soil with the optimum moisture content. Such tendency was transforming to the dry side as the compaction energy was increased. The effect of water on the grain crushability of soil was high in the coarse grained soil. The specific surface area of WK soil sample, when compacted under the condition of air dried and under the optimum moisture content, was constant regardless of the compaction energy. When the weathered granite soil and river sand with the same grain size were compacted with low compaction energy, the weathered granite soil with crushability had higher dry density than river sand. However, when the compaction energy reached to certain point over limitation, the river sand had higher dry density than the weathered granite soil. The coefficient of permeability was lowest in the wet side rather than in the optimum moisture content, when the soil was compacted by adjusting soil water content. The reduction of permeability of soil due to the compaction was more apparent in the weathered granite soil than in the river sand. The highly significant correlation coefficient was obtained between the amount of particle breakage and dry density of the compacted soil.

• 한국조경학회지
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• 제39권1호
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• pp.117-123
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• 2011

본 연구는 빗물 활용 옥상녹화에서 식재기반 차이에 따른 한라구절초의 생육 변화를 살펴보고, 적합한 토심과 토양배합비를 제시함으로써 옥상조경 식물소재로 활용성을 높이고자 한다. 토심(15cm, 25cm)과 토양배합비(SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$)를 각각 다르게 실험구를 조성하였으며, 내건성과 관상가치가 뛰어난 한라구절초를 식재한 후 초장, 녹피율, 엽록소 함량, 생체중과 건조중, T/R율 등을 측정하였다. 토심 15cm처리구에서 토양배합비에 따른 한라구절초의 초장의 경우 통계적 유의성은 발견되지 않으나, 전반적으로 PPL배합토인 $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$가 사양토인 SL보다 높았다. 토심 25cm처리구의 경우, SL < $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ < $P_4P_4L_2$ 순으로 초장이 길었다. 녹피율의 경우 토심 15cm처리구에서는 초장과 같이 토양배합비에 의한 차이는 뚜렷하지 않았으나, 수치적으로는 SL처리구에서 가장 낮았다. 토심 25cm처리구의 전체적으로 86~89%의 높은 피복률을 나타냈다. 엽록소 함량은 토심 15cm처리구에서 SL이 가장 높게, $P_5P_3L_2$이 가장 낮았으며, 토심 25cm처리구에서는 $P_4P_4L_2$과 SL에서 가장 높은 값을, $P_7P_1L_2$에서 가장 낮은 값을 보였다. 생체중과 건물중의 경우 배합비보다는 토심에 따른 차이가 더 뚜렷하여 토심 25cm처리구가 15cm처리구보다 높았다. 따라서 빗물활용 옥상녹화 식재지반에 있어 한라구절초의 생육은 토심 25cm가 토심 15cm보다, PPL배합토, 특히, 피트모스함량이 높은 $P_4P_4L_2$이 사양토보다 더 적합한 생육환경을 제공해 주는 것으로 분석되었다.

• 한국지반환경공학회 논문집
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• 제15권1호
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• pp.25-34
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• 2014

본 연구의 목적은 개량체 구조형상변화에 따른 복합지반에서의 역학 및 침하특성을 분석하는 것에 있다. 본 연구의 실험은 원형토조에 강도 및 치환율별로 격자형 개량체를 만들어 복합지반을 조성한 후 응력을 재하하는 방식으로 총 9 케이스를 수행하였다. 또한 심도별 응력분포 및 응력분담비 등을 분석하기 위해 유한요소해석을 실내 모형실험과 동일조건으로 모델링하여 해석하였다. 연구결과, 격자형 개량체로 구성된 복합지반은 원형 개량체에 비해 저치환율을 제외한 중간 및 고치환율에서 응력분담비가 증가하며 그 결과, 침하량은 감소하는 경향을 보였다. 본 연구는 구조형상 변화에 따른 형상효과비 및 침하저감계수 제시를 통해 부족한 복합지반의 개량체 구조형상에 대한 연구 참고자료 및 향후 추가 연구에 도움이 될 것으로 판단된다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.81-82
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• 2018

In this paper, we investigate the characteristics of wet soil concrete according to the addition ratio of liquefaction red mud addition rate by liquefying red mud. as a result, the compressive strength decreased and the water absorption ratio increased as the liquefaction red mud addition rate increased.

• 한국농공학회논문집
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• 제51권5호
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• pp.51-58
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• 2009

The total recovery ratio test on undisturbed clay soil sampling in the field and the finite element method analysis on modified static state of penetration process were conducted for the purpose of deciding the most important factor among the shape factors of thin wall tube. The adhesion between tube wall and soil did not decrease although internal clearance ratio of tube increased within the little change of tube area ratio. The most part of disturbance occurred in the tip of sampling tube during the penetration. The longitudinal displacement was larger than the lateral displacement because soil was confined laterally after being entered into tube, and also the longitudinal displacement was larger in the upper part of the sample tube than in the lower part.