• 제목/요약/키워드: 간극량

검색결과 240건 처리시간 0.024초

Effect of Plant Population on the Growth, Yield and Quality of Sohyang (Nicotiana tabaccum L.) (소향(Nicotiana tobaccum L.)의 재식밀도와 생육, 수량 및 품종)

  • Bae, S.K.;Lim, H.G.;Son, S.H.
    • KOREAN JOURNAL OF CROP SCIENCE
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    • 제26권2호
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    • pp.207-211
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    • 1981
  • The effect of plant populations - 16,667, 14,285, 12,499 or 10,7l4/10a on the agronomic characteristics of an aromatic tobacco, Sohyang was investigated for two years. The growth and number of suckers produced decreased as the population increased. The leaf area index (L.A.I) was higher in thinner planting, but there was no significant difference in weight per unit leaf area between treatments. Yield was highest, 1 24 kg/ l0a, in 16,667 plantings per l0a, but quality was not different among densitites tested. Similar trends were observed in monetary value per l0a. Concentrations of total alkaloids and nitrogen were low in denser planting, but no significant difference was observed in total sugar. The results suggest that about 16,000/10a more would be optimum number of plants for Sohyang.

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Investigation on Water Leakage-Induced Tunnel Structure and Ground Responses Using Coupled Hydro-Mechanical Analysis (수리역학 연계해석을 이용한 누수로 인한 터널 구조물 및 지반 거동의 분석)

  • Dohyun Park
    • Tunnel and Underground Space
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    • 제33권4호
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    • pp.265-280
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    • 2023
  • Water leakage in tunnels is a defect that can affect tunnel stability and the ground movement by changing the stress and pore water pressure of the surrounding ground. Long-term or large-scale water leaks may lead to damage of tunnel structure and the surrounding environment, such as tunnel lining instability and ground surface settlement. The present study numerically investigated the effects of water leakage on the structural stability of a tunnel and the ground behavior. The tunnel was assumed to be under undrained conditions for preventing the inflow of the surrounding water and leaks occurred in the concrete lining after completion of the tunnel construction. A coupled hydro-mechanical analysis using a TOUGH-FLAC simulator developed in Python was conducted for assessing the leakage induced-behavior of the tunnel structure and ground under different conditions of the amount and location of water leak. Additionally, the effect of hydro-mechanical coupling terms on the results of coupled response was investigated and discussed.

A Study for Permeability as Mixing Ratio at Bentonite-mixed Soil (벤토나이트 혼합토의 혼합비에 따른 투수성 연구)

  • Ju Jae-Woo;Suh Kyeh-Won;Park Jong-Beom
    • Journal of the Korean Geotechnical Society
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    • 제22권1호
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    • pp.45-52
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    • 2006
  • A theoretical equation, from which we can get a suitable ratio of bentonite at bentonite-mixed soil, was derived for desigri of the impermeable condition. Bentonite is a soil with great expansion property and it has the permeability lower than $1\times10^{-7}cm/sec$ in spite of its maximum expansion state. Accordingly if the void of soil is filled with the liquid of bentonite, water will flow only through the veid of bentonite liquid. And the permeability of bentonite-mixed soil will always satisfy the condition as impermeable zone. However, because it is very difficult to mix uniformly bentonite with soil, it is thought that the actual mixing ratio fur the impermeable zone will be grater than that by theoretical equation. Permeability tests were performed to check the equation and a modified equation was suggested from the experimental results.

Characterization of Composite Ground Reinforced with Recycled-Aggregate Porous Concrete Pile (RAPP) (순환골재 다공질 콘크리트말뚝(RAPP)에 의해 보강된 복합지반의 거동 특성)

  • You, Seung-Kyong;Kim, Se-Won;Lee, Chul-Ho;Choi, Hang-Seok
    • Journal of the Korean Geotechnical Society
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    • 제25권11호
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    • pp.117-130
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    • 2009
  • In this paper, a series of laboratory chamber tests were carried out to evaluate the applicability of a porous concrete pile fabricated with recycled aggregates (RAPP) for the soft ground improvement. While performing the laboratory chamber tests for the RAPP, the surface settlement, excess pore pressure and vertical stress distribution with time were compared with those of SCP provided by You (2003) under the same experimental condition. In addition, the experimental results were compared with the numerical simulation using ABAQUS in this study. The results show that the settlement reduction is significantly enhanced due to the stress-sharing mechanism between the RAPP and soil formation by stress concentration on the RAPP. Furthermore, the comparison of consolidation rate shows that the RAPP can accelerate consolidation as well, which behaves as a vertical drain.

Numerical Analysis on Drained and Undrained Pullout Capacity in Reinforced Soil (보강토에서의 배수 및 비배수 인발력에 대한 수치해석)

  • Lee, Hong-Sung;Son, Moo-Rak
    • Journal of the Korean Geotechnical Society
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    • 제23권4호
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    • pp.113-123
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    • 2007
  • In order to ensure the stability of reinforced structures backfilled with low permeability soil, it is very important to determine the change in undrained pullout capacity compared to drained pullout capacity prior to design. In this research, a series of numerical analyses on laboratory pullout tests have been performed on different materials (clean sand, 5, 10, and 15% silty sand), different overburden pressures (30, 100 and 200 kPa), and different drainage conditions (drained and undrained) in order to compare drained pullout capacity with undrained pullout capacity. The results of numerical analysis also have been compared with the results of the laboratory pullout tests. The analysis results show that both drained and undrained pullout capacity are influenced by silt contents and increase with increase of friction angle of the soil and overburden pressure. In undrained condition, the effective stresses acting on the reinforcement decrease as excessive pore pressures are generated, resulting in decrease in pullout capacity; 57% for 30 kPa, and 70% for 100 and 200 kPa. These results show a good agreement with the results of the laboratory pullout tests performed under the same condition.

Analysis of Fine Particle Transfer and Shear Strength Increase Using PFC in Permeation Grouting (PFC를 이용한 침투그라우팅시 미세입자의 이동 및 전단강도증가 해석)

  • Lee, Wan-Ho;Lim, Heui-Dae
    • Journal of the Korean Geotechnical Society
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    • 제23권11호
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    • pp.49-58
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    • 2007
  • Numerical experiments using a distinct element code (PFC3D) were carried out for the analysis of grout-material transfer in soil layers and also for the analysis of increase in mechanical strength after permeation grouting. For rapid analysis, up-scaling analysis in length scale was adopted, and the following observations were made from the numerical experiments. Firstly, the relative size of grout material with respect to the in situ soil particles controlled the transfer distance of the grout particles. When the size of grout particle was 0.2 to 0.25 times of the in situ soil particles, clogging of pore spaces among the in situ soil particles occurred, resulting in restricted propagation of grout particles. It was also found that there was a threshold value in the size of grout particle. Below the threshold value, the transfer distance of the grout particle did not increase with the decrease of particle size of the grout material. Secondly, the increase in cohesion and internal friction angle was observed in the numerical specimen with grouting treatment, but not with the untreated specimen.

A Study on Consolidation Characteristic of Dredged Fill Using Geotechnical Centrifuge (원심모형시험에 의한 준설지반의 압밀특성연구)

  • Kim, Hee-Chul;Kim, Heung-Seok;Lee, Song
    • Journal of the Korean Geotechnical Society
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    • 제24권10호
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    • pp.45-55
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    • 2008
  • In this study, the in-situ model test has been conducted to estimate and analyze consolidation behavior of the ground by using the miniature test that reconstructs economically geotechnical behavior of in-situ full scale structure. To analyze the relation of effective stress, void ratio and coefficient of permeability at the self-weight consolidation stage, the low stress seepage consolidation test has been conducted and the involution function of constitutive equation had been obtained from the result of the curve fitted seepage consolidation test. As a result of the numerical analysis that had been conducted on the representative section using a constitute equation, final settlement was similar to those of self-weight consolidation of the centrifugal model test. But it was more or less smaller. It seems that these trends are caused by the difference between estimated values.

Comparison of Characteristics on Electrolyzed Water Manufactured by Various Electrolytic Factors (전해인자에 따른 전기분해수의 특성 비교)

  • Kim, Myung-Ho;Jeong, Jin-Woong;Cho, Young-Je
    • Korean Journal of Food Science and Technology
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    • 제36권3호
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    • pp.416-422
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    • 2004
  • Efficacy of surface sterilization and physicochemical properties of electrolyzed water manufactured depending on electrolyte, materials, and type of electrolytic diaphragm used were investigated. Physical properties of electrolyzed water manufactured from diaphragm system showed the highest effectiveness under at distance between diaphragms of 1.0 mm and 20% NaCl supplying rate of 6 mL/min. ORP, HClO (should defined) content, and pH at above conditions were 1,170 mV, 100 ppm, and 2.5, respectively. Two-stage electrolyzed system was more effective than one-stage one. Electrolyzed water manufactured from non-diaphragm system at 4 mL/min supplying rate of 20% NaCl was similar to the most effective diaphragm system, whereas ORP, HClO content, and pH were 800 mV, 200 ppm, and 9, respectively. Sealed electrolyzed water could be preserved more than one month at room temperature with ORPs of 750 and 1,150 mV in non-diaphragm and diaphragm systems, respectively, and at HClO content of 100 ppm. Physicochemical properties of electrolyzed water manufactured from electrolytic diaphragm of $IrO_{2}$ and Pt+Ir were more effective than that of Pt. ORP and HClO contents of electrolyzed water manufactured from various electrolytes were high in order of NaCl>KCl>$CaCl_{2}$, whereas no differences were observed among electrolytes in sterilization efficacy. Twelve kinds of microorganisms tested (initial total count, $10^{5}-10^{6}CFU/mL$) were sterilized within 1-2 min by electrolyzed water.

Porewater Pressure Predictions on Hillside Slopes for Assessing Landslide Risks(I) -Comparative Study of Groundwater Recharge- (산사태 위험도 추정을 위한 간극수압 예측에 관한 연구(I) -지하수 유입량의 비교 연구-)

  • Lee, In-Mo;Park, Gyeong-Ho;Im, Chung-Mo
    • Geotechnical Engineering
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    • 제8권1호
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    • pp.81-102
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    • 1992
  • Landslides on hillside slopes with shallow soil cover over a sloping bedrock are frequently caused by increases in porewater pressures following of heavy rainfall and it is one of the most important factors of assessing the risk of landslide to predict the groundwater level fluctuations in hillslopes. This paper presents the comparative study of three unsaturated flow models developed by Sloan et al., Reddi, L.N., and Thomas, H.A., Jr., respectively, which are used to predict the increase of groundwater levels in hillside slopes. The parametric study for each of models is also presented. The Kinematic Storage Model(KSM) developed by Sloan et at. is utilized to predict the saturated groundwater flow. They are applied to the two sites in Korea so as to examine the possibility of use in the groundwater flow model. The results show that two unsaturated models developed by Sloan et al. and Reddi, L. N. are largely affected by the uncertain parameters like saturated permeability and saturated water content : the abed model has the potential of use in unsaturated flow model with the optimal estimates of model parameters utilizing available optimization techniques. And it is also found that the KSM must be modified to account for the time delay effect in the saturated zone. The results of this paper are able to be utilized in developing the predictive model of groan dwater level fluctuations in a hillslope.

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Shear Strength and Deformation Characteristics of Lightweight Soils Mixed with Tire Powder (타이어 가루를 섞은 경량혼합토의 전단강도와 변형특성)

  • Yoon, Gil Lim;Yoon, Yeo Won;Ahn, Kwang Hyun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • 제32권6C호
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    • pp.259-265
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    • 2012
  • This paper investigates engineering characteristics of lightweight soils mixed with air foam and tire powder. Lightweight soils could be used as foundation materials, back-fills of reducing vibrating or abutment, and so on. Unconfined and triaxial compression tests were carried out to analyze strength and deformation characteristics of lightweight soils by changing target moist unit weight and cement contents. In comparison with strength characteristics of two different kinds of lightweight soils with same most unit weights ($13kN/m^3$), unconfined compression tests showed similar compressive strength, however, triaxial compression tests showed that compressive strength of lightweight soils mixed with waste tire powder was relatively larger strength than that of lightweight soils mixed with air foam because of elasticity of waste tire powder. Also, unconfined and triaxial compressive strengths of most of lightweight soils increase with increases of moist unit weight and cement contents. However, the strength of lightweight soils mixed with air foam under $11kN/m^3$, when moist unit weight exceeds a certain cement contents, decreases even though cement contents increase because of the effect in a void gap of air foam.