• Title/Summary/Keyword: air permeability coefficient

Search Result 58, Processing Time 0.029 seconds

Prediction of Soil-water Characteristic Curve and Unsaturated Permeability Coefficient of Reclaimed Ground (불포화 준설매립 지반의 흙-수분 특성곡선 및 불포화 투수계수 예측)

  • 신은철;이학주;오영인
    • Journal of the Korean Geotechnical Society
    • /
    • v.20 no.1
    • /
    • pp.109-120
    • /
    • 2004
  • There has been outstanding research on the soil-water characteristic curves of unsaturated soils over the past several decades. Unfortunately, unsaturated soil mechanics has not been considered as an important factor in Korea. In this paper, laboratory test and numerical analysis(SoilVision Professional ver 3.04) were performed to investigate the prediction method of soil-water characteristic curve and unsaturated permeability coefficient in reclaimed ground. The pressure cell, desiccator, and tensiometor tests were conducted on three types of reclaimed soils(dredged soil, sand, weathered granite soil). Numerical analysis was executed to compare the results with the laboratory test results and also compared with the results of each prediction method. Based on the laboratory test, three different types of soils have shown different soil-water characteristic curves. The hysteresis fir these soils is clearly defined. As a result of numerical analysis, Fredlund & Xing's method and Fredlund & Wilson's model proved to worke out well for reclaimed ground soils in Korea. Also, predicting method based on the soil-water characteristic curves from the particle-size distributions is flirty reliable for estimating unsaturated permeability coefficient.

The Prediction model of Carbonation Process Using the Air Permeability Coefficient for Concrete (콘크리트의 투기계수를 이용한 중성화진행 예측모델)

  • Lim, Chang-Hyuck;Kim, Gyu-Yong;Lee, Tae-Gyu;Lee, Eui-Bae;Didolkar, Rahul B.;Kang, Suk-Pyo
    • Proceedings of the Korea Concrete Institute Conference
    • /
    • 2010.05a
    • /
    • pp.221-222
    • /
    • 2010
  • In this study an expression is obtained the model equation for the prediction of carbonation based on the time and interaction velocity between $CO_2$ and $Ca(OH)_2$ diffusion coefficient.

  • PDF

Analysis of Energy Performance and PMV Improvement by Application of Passive Factor for Office Building Renewal (오피스건물 리뉴얼시 패시브 요소적용에 따른 에너지성능 및 PMV 개선에 관한 연구)

  • Hong, Won-Pyo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
    • /
    • v.28 no.12
    • /
    • pp.55-64
    • /
    • 2014
  • This paper presents a case study to investigate the monthly calculation method of ISO 13790 applied for a office building. The energy performance analysis according to improvement of insulation and air permeability of windows in K office buildings is investigated by means of building energy efficiency rating tool ($ECO_2-OD$). The K building energy system is tested experimently by the measurement of PMV(predicted mean vote) for the control of indoor thermal environment and heat transmission coefficient of windows and interior walls respectively, before and after the example K office building is remodeled passively. Therefore, Internet based energy assessment program of energy efficiency rating of office building can be applied as a program for the annual energy requirement and for evaluation of energy savings from the experimental and simulation results.

A Study on the Acoustical characteristics of Curtain Fabrics (part 1) -by Constructional Characteristics of Curtain Fabrics- (Curtain감의 음향특성에 관한 연구(제1보) -Curtain감의 구성특성을 중심으로-)

  • Chung Un Ja;Kang Kyung Ja;Cho Hyun Hok
    • Journal of the Korean Society of Clothing and Textiles
    • /
    • v.3 no.2
    • /
    • pp.23-27
    • /
    • 1979
  • The normal transmission characteristics of curtain fabrics were measured by sound level meter. Transmission coefficient was calculated by difference of incidence SPL and transmission SPL. The relation between this value and factors relating to the structure of curtain fabrics were investigated. The results of experiment were shown follow; 1. Transmission coefficients(approximately over $95\%$) of sound in curtain fabrics differ from according to the frequency. It was lower in 500Hz frequency, on the other hand, higher in 400, 640. 1000Hz frequency. It had a tendency to frequency among the samples. 2. The greater cover factor of sample was, the smaller the transmission coefficient of sound was. It was not influenced by thickness. 3. Air permeability was increased as the transmission coefficient of sound were greater. (correl. ation coefficient=0.83) 4. In the case of special single cloth weave(special honeycomb weave), there sometimes took place that transmission SPL was greater than incidence SPL.

  • PDF

A Study on the Liquid Flow Characteristics in Layer Porous Media (다공질매체내의 유체유동 특성에 관한 연구)

  • Lee, C.G.;Hwang, C.B.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.5 no.4
    • /
    • pp.243-248
    • /
    • 1993
  • In this research, unsteady groundwater flow in unconfined and homogeneous three layer aquifers is studied theoretically and experimentally. Numerical solutions are obtained by Runge Kutta and Runge Kutta Gill method after transforming the governing nonlinear partial differential equations to nonlinear ordinary differential equations. Experimental apparatus includes a test section filled with fine, medium and coarse sands. Experimental results are compared with the numerical solutions and both experimental and numerical results correspond well with each other. This numerical approach may be also applied to the cases which have more aquifers.

  • PDF

Gas Permeation Properties of Polymeric Membranes for Biosensor Prepared from Poly(vinyl chloride) Derivatives (Poly(vinyl chloride) 유도체로부터 제조된 바이오센서용 고분자막의 기체 투과특성)

  • Lim, Chun-Won;Kim, Wan-Young;Lee, Youn-Sik;Yoon, Jeong-Won;Jeong, Yong-Seob
    • Applied Chemistry for Engineering
    • /
    • v.10 no.3
    • /
    • pp.362-366
    • /
    • 1999
  • Membranes for biosensor were prepared from poly(vinyl chloride) (PVC)l derivatives using the solution casting method, and their gas permeabilities were studied. The polymer membranes dried slowly in air showed higher permeability coefficients than those dried in vacuum. The permeabilily coefficients of carboxylated poly(vinyl chloride) (CPVC) membranes for $O_2$ and $CO_2$ decreased as the pressure of the feed gas increased. The addition of dioctylphthalate (DOP) enhanced the permeation rates for $O_2$ and $CO_2$. For example, the permeability coefficients of CPVC membranes containing 30 wt. % DOP for $O_2$ and $CO_2$ at 100 psig were 2.03 and 0.96 Barrer, respectively, which were about 4~5 times higher than those of the membranes without DOP. Poly(vinyl chloride-co-vinyl acetate-co-vinyl alcohol) (Syn-PVCAcAl) obtained by hydrolysis of poly(vinyl chloride-co-vinyl acetate (PVCA) showed a higher permeability coefficient for $CO_2$ in the presence of DOP than that for commercial PVCAcAl, but did not show any significant difference in permeability for $O_2$.

  • PDF

Basic Study on the Characteristics of Wooden Sidewalk Pavement Material using Wood Waste Chip (폐목재 칩을 활용한 목질계 보도포장재의 특성에 대한 기초연구)

  • Choi, Jae Jin;Song, Jin Woo
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.31 no.3D
    • /
    • pp.413-420
    • /
    • 2011
  • An experiment was conducted to suggest the road pavement material combining wooden chip crushed from little useful roots and branches from logging sites or wood waste from construction sites with urethane resin. For the specimen, the mass ratio of urethane resin to construction wood waste chip/lumber waster chip was set to three different levels of 0.5, 0.75, and 1.0, which was measured, mixed with mixer, and molded; 7 days after, tensile strength test, elasticity test using golf balls and steel balls, permeability coefficient measurement, and flammability test were executed. As the result, the tensile strength of the specimen at the dry state in the air exhibited the range of 0.2-1.1MPa, and there was no change after 7 days of aging. When submerged in water, however, the strength was partially diminished; the diminishing rate was greater for less urethane resin usage, and therefore it appears desirable to set the mass ratio of resin to the wood waste chip over 0.75 to consider the moisture intrusion by precipitation and such. As the result of elasticity test, the GB and SB coefficients of the specimen using wood waste chips and urethane resin were measured to be low at below 20%, exhibiting excellent elasticity as road pavement material. Also, the permeability coefficient was over 0.5mm/sec for specimens of all combinations, exceeding the standard value required after construction for permeable pavement material, and the flammability of wood-type pavement material was evaluated to have no practical issues.

An Empirical Study on the Characteristics of Pore Water Pressure Reaction in Colluvium Model (붕적층내의 간극수압 반응에 관한 실험적 연구)

  • 정두영;최길렬
    • Geotechnical Engineering
    • /
    • v.8 no.2
    • /
    • pp.59-70
    • /
    • 1992
  • This work is to study experimentally the measurment of pore air pressure according to rainfall in colluvium model and the characteristics of pore water pressure according to increasement of artesian ground water head. After modeling a geological feature of the Tertiary formation, the experiment was performed about sixty times on three kinds of soil. This experimental results showed the variation of pore water and pore air pressures with time, the change of void ratio and appling pressure head in the nonsaturated soil. It can be also expressed by the final pore water and the air reaction ratios and then formularizing the relationship between the permeability coefficient and the void ratio. In the results of this experiment, the patterns of the pore water pressure reaction are classified by the step-type and the wave-type, and the time-lag to reach final point of pore water pressure is in order sand, sandy silt and clayey sand.

  • PDF

A Study on the Liquefaction of Saturated Sand Layer under Oscillating Water Pressure (수압변동에 의한 포화 모래층의 액상화 연구)

  • Howoong Shon;Hyun-Chul Lim;Dae-Geun Lee
    • Journal of the Korean Society of Groundwater Environment
    • /
    • v.7 no.2
    • /
    • pp.59-65
    • /
    • 2000
  • The vertical distribution of pore water pressure in the highly saturated sand layer under the oscillating water pressure is studied theoretically and experimentally. By the experiments it is shown that the water pressure acting on the sand surface propagates into the sand layer with the damping in amplitude and the lag in phase, and that the liquefaction, the state that the effective stress becomes zero, occurs under certain conditions. These experimental results are explained fairly well by the same theoretical treatment as for the ground water problems in the elastic aquifer. The main characteristics of liquefaction clarified by the analysis are as follows: 1) The depth of the liquified layer increases with the increase of the amplitude and the frequency of the oscillating water pressure. 2) The increase of the volume of the water and the air in the layer increases the liquified depth. Especially the very small amount of the air affects the liquefaction significantly. 3) The liquified depth decrease rapidly with the increase of the compressibility coefficient of the sand. 4) In the range beyond a certain value of the permeability coefficient the liquified depth decrease with the increase of the coefficient.

  • PDF

LIQUEFACTION OF SAND SEABED INDUCED BY WATER PRESSURE WAVE (수압변동에 의한 해저사질층의 액상화 현상연구)

  • HoWoongShon
    • Journal of the Korean Geophysical Society
    • /
    • v.4 no.3
    • /
    • pp.197-203
    • /
    • 2001
  • The vertical distribution of pore water pressure in the highly saturated sand layer under the oscillating water pressure (water wave) us studied theoretically and experimentally. By the experiments it is shown that the water pressure acting on the sand surface propagates into the sand layer with the damping in amplitude and the lag in phase, and that the liquefaction, the state that the effective stress become zero, occurs under certain conditions. These experimental results are explained fairly well by the same theoretical tearment as for ground water problems in the elastic aquifer. The main characteristics of liquefaction clarified by the analysis are as follows: 1) The depth of the liquified layer increases with the increase of the amplitude and the frequency of the oscillating water pressure. 2) The increase of the volume of the air in the layer increases the liquified depth. Especially the very small amount of the air affects the liquefaction significantly. 3) The liquefied depth decrese rapidly with the increase of the compressibility coefficient of the sand. 4) In the range beyond a certain value of the permeability coefficient the liquified depth decrease with the increase of the coefficient.

  • PDF