• Title/Summary/Keyword: 간극량

Search Result 240, Processing Time 0.024 seconds

Theoretical Formulation of Porous Medium Behavior Depending on Degree of Saturation (포화도에 따른 다공질 매체 거동의 이론적 정식화)

  • Park, Tae Hyo;Jung, So Chan;Kim, Won Cheul
    • Journal of the Korean GEO-environmental Society
    • /
    • v.2 no.3
    • /
    • pp.81-88
    • /
    • 2001
  • The behavior of porous medium is modeled by linear thermoporoelastic behavior, linear poroviscoelastic behavior, poroplastic behavior, and poroviscoplastic behavior, etc. The behavior has, in general, a complicated aspect which makes a mechanical description of the problem with time. Constitutive modeling for deformation behavior of porous medium with coupling effects is needed since there is interaction between the constituents in pores with a relative velocity to each other. In this work, it is explained 3-dimensional behavior depending on degree of saturation for porous medium composed of homogeneous, isotropic materials. It is obtained the governing equations based on continuum porous mechanics. In addition, it is developed constitutive model which can be understood of behavior for porous medium which can be understood, analysed behavior of porous medium. It can be accomplished exact analysis and prediction of behavior in porous medium. The behavior for porous medium is analysed exactly, and the prediction of deformation behavior is accomplished. Consequently, it will be basis to analyze 3-dimensional behavior in municipal solid waste landfill, and the practical using of porous medium ground which are composed of nonhomogeneous, anisotropic materials can be done widely.

  • PDF

Consolidation Characteristics of Soft Ground with Artesian Pressure (피압에 따른 연약지반의 압밀 거동)

  • Yun, Daeho;Kim, Jaehong;Kim, Yuntae
    • Journal of the Korean GEO-environmental Society
    • /
    • v.17 no.2
    • /
    • pp.31-39
    • /
    • 2016
  • Vertical drain has usually been used to accelerate the consolidation of soft clay deposits with high moisture content. Busan thick clay deposits are subjected to artesian pressure from an aquifer in sand and gravel layers. However, effect of artesian pressure existing in drainage-installed soft ground on consolidation behaviors is not well known. This paper investigates the consolidation behavior of drainage-installed soft ground at the Nakdong river estuary with artesian pressure and without artesian pressure. A series of one-dimensional large size column test was carried out to find out the consolidation characteristics of clay. Test results indicated that total settlement of clay with artesian pressure was higher than that without artesian pressure because effective stress decreased due to upward flow. Dissipation rate of excess pore water pressure delayed and excess pore water pressure did not fully dissipate in clay layer with artesian pressure. Undrained shear strength of clay ground with artesian pressure was lower than that without artesian pressure.

Study on the Relationship Between Emission Signals and Weld Defect for In-Process Monitoring in CO2 Laser Welding of Zn-Coated Steel (아연코팅 강판의 CO2 레이저용접시 인프로세스 모니터링을 위한 측정신호와 용접결함과의 관련성 연구)

  • Kim, Jong-Do;Lee, Chang-Je
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.34 no.10
    • /
    • pp.1507-1512
    • /
    • 2010
  • In this study, the plasma induced by $CO_2$ laser lap welding of 6t Zn coated steel used for ship building was measured using photodiodes and a microphone. Then, the welding phenomenon with gap clearance of lap joint was compared with RMS-treated signal. Thus, we found that intensity of the RMS-treated signal increased with Zn vaporization; further, the presence of defects results in rapid variations with the RMS value as a function of lap-joint parameters. Besides, the FFT value of the raw signal with variations of changing welding parameters was calculated, and then the calculated FFT frequency value was set as the bandwidth of digital filter for a more accurate in-process monitoring. The RMS values were acquired by filtering the raw signal. By matching the weld beads and the calculated RMS values, we confirmed that there is a strong relationship between the signals and the defects.

Effect of Tunneling and Groundwater Interaction on Tunnel Behavior (터널시공과 지하수의 상호작용이 터널의 거동에 미치는 영향)

  • Yoo, Chung-sik;Kim, Sun-bin;Bae, gyu-jin;Shin, hyu-sung
    • Journal of Korean Tunnelling and Underground Space Association
    • /
    • v.7 no.2
    • /
    • pp.97-108
    • /
    • 2005
  • This paper presents the effect of tunneling and groundwater interaction on tunnel behavior. As part of this study, design issuses for tunneling situations similar to that considered in this study are first identified. A parametric study is then conducted on tunneling situations frequently encountered in Seoul area using a 3D stress-pore presure coupled finite-element model with emphasis on the effects of ground and lining permeabilities. The results indicate that tunneling in water bearing ground results in a deeper and wider settlement trough, increased axial thrusts in shotcrete lining than those without the groundwater. Also revealed is that the axial thrusts in shotcrete lining are governed by the relative permeability between the ground and the lining. Design implications of the findings from this study are discussed.

  • PDF

Application of Ultrasonic Energy to Fast Consolidation of Soft Clays (연약지만 압밀 촉진을 위한 초음파 에너지의 활용)

  • Park, Ji-Ho;Hwang, Jung-Ha;Kim, Young-Uk
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.9 no.4
    • /
    • pp.1039-1042
    • /
    • 2008
  • Dredged fills have been widely used to secure a land for the engineering activities. Before the useful application of the area, the soils should be consolidated to acquire the aquate shear strength. Several research projects have attempted to develop a method fur accelerating the consolidation of soft clay. Our study examined the effect of ultrasonic energy on the consolidation of soft clay, Tests were conducted using specially designed and fabricated equipment that was capable of directly applying ultrasonic energy to soil samples during consolidation tests. The specimens were prepared from slurry using a centrifuge facility, and tests were conducted at various levels of ultrasonic power and treatment time. The study showed that ultrasonic energy had a considerable effect on consolidation time, suggesting that ultrasound can be used to reduce the consolidation time of soft clay.

The Development of Rail-Transport Operation Control based on Unsaturated Soil Mechanics Concept (불포화토이론을 이용한 강우시 열차운전규제기준 개발)

  • Kim, Hyun-Ki;Shin, Min-Ho;Kim, Soo-Sam
    • Journal of the Korean Society of Hazard Mitigation
    • /
    • v.4 no.1 s.12
    • /
    • pp.25-31
    • /
    • 2004
  • Infiltration of rainfall causes railway embankment to be unstable and may result in failure. Basic relationship between the rainfall and stability of railway embankment is defined to analyze the stability of embankment by rainfall. An experimental study for defining of infiltration rate of rainfall into slope is conducted in the lab. The results of Rainfall Infiltration show that rainfall Infiltration is not equal to infiltration as like reservoir because rate of rainfall infiltration is controlled by slope angle. Based on these results, boundary condition of rainfall is altered and various numerical analysis are performed. The variation of shear strength, the degree of saturation and pore-water pressure for railway slope during rainfall can be predicted and the safety factor of railway slope can be expressed as the function of rainfall amount, namely rainfall index. Therefore, it is judged that this rainfall index can be a good tool for the rail-transport operation control.

Engineering Characteristics of Diatom Modified Soil Mixture (Diatom 혼합토의 공학적 특성)

  • Kim, Kyu-Sun
    • Journal of the Korean Geotechnical Society
    • /
    • v.28 no.5
    • /
    • pp.77-84
    • /
    • 2012
  • The engineering characteristics of natural sediments containing diatom microfossils have been investigated for their abnormal deformation and strength behavior for a few decades. The presence of disk or hollow shape diatoms causes low compressibility, high hydraulic conductivity, and high shear strength of sediments. Some of these unusual differences show the characteristic of diatom owing to the interlocking of large interparticle porosity and angular particles. This phenomenon implies the possible use of diatom as modification materials to change the engineering performance of soil mixtures. This paper describes the engineering characteristics of diatom-kaolin mixture to investigate the engineering properties of diatom modified soils using conventional geotechnical tests and elastic and electromagnetic wave propagation tests. Experimental test results show the performance improvement by increasing diatom contents and the performance degradation by the breakage of interlocking between diatom particles under high effective stress.

Ethanol Concentration Sensor Using Microfluidic Metamaterial Absorber (에탄올의 농도를 검출하기 위한 미세유체 메타물질 흡수체)

  • Kim, Hyung Ki;Yoo, Minyeong;Lim, Sungjoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.26 no.5
    • /
    • pp.506-513
    • /
    • 2015
  • In this paper, we proposed a novel ethanol concentration sensor using microfluidic metamaterial absorber. The metamaterial absorber comprises a split-ring-cross resonator(SRCR) and a microfluidic channel. The SRCR can generate LC resonance that is very sensitive to changes in the effective dielectric constant around the capacitive gap. In addition, microfluidic channels can change the effective dielectric constant of the dielectric substrate by using an infinitesimal quantity of a liquid on the order of microliters. The proposed absorber can detect the electrical properties of different concentration of ethanol. The performance of the proposed absorber is demonstrated using the absorption measurements of a fabricated prototype sample with waveguides. In addition, the simulated results and measurement results show good agreement.

A Study of Consolidation Behavior of Clay Ground with Partially Penetrated PVD under Artesian Pressure (연직배수재가 부분 관입된 점토지반의 피압에 따른 압밀 거동에 관한 연구)

  • Yun, Daeho;Nguyen, Ba Phu;Kim, Jaehong;Kim, Yuntae
    • Journal of the Korean Geosynthetics Society
    • /
    • v.15 no.1
    • /
    • pp.47-57
    • /
    • 2016
  • Many researchers reported that artesian pressure exists in thick soft ground of Busan Nakdong river estuary. Artesian pressure in soft ground could affect rate of consolidation, settlement and drainage capasity of prefabricated vertical drain(PVD). This paper investigated consolidation behaviors of soft ground with partially penetrated PVD subjected to artesian pressure. Laboratory tests with 1-dimensional large column equipment and their numerical analyses were carried out. Test results showed that the consolidation settlement of clay ground with artesian pressure was higher than that without artesian pressure. Due to artesian pressure, the dissipation rate of excess pore water pressure was reduced in soft ground with artesian pressure, especially at bottom part of clay ground. Numerical results were in good agreement with experimental test results.

The Behavior of Piled Bridge Abutments Subjected to Lateral Soil Movements - Design Guidelines - (측방유동을 받는 교대말뚝기초의 거동분석 (II) - 측방유동 판정기준 -)

  • 이진형;서정주;정상섬;장범수
    • Journal of the Korean Geotechnical Society
    • /
    • v.19 no.1
    • /
    • pp.21-29
    • /
    • 2003
  • In this study, practical guidelines to check the possibility of some lateral movement of piled abutment were investigated. In these tests, both the depth of soft clay and the rate of embankment construction are chosen to examine the effect on lateral soil movements. The depth of soft clay layer varies from 5.2 m to 11.6 m, and the rate of embankment construction has two types : staged construction(1m/30days, 1m/15days) and instant construction. Various measuring instruments such as LVDTs, strain gauges, pressure cells, and pore pressure transducers are installed in designed positions in ordo. to clarify the soil - pile interaction and the short and long term behavior f3. piled bridge abutments adjacent to surcharge loads. The validity of the proposed guidelines by centrifuge test was compared with the observed performance by lateral movement index, F(Japan Highway Public Corporation) and modified I index(Korea Highway Corporation). Based on the results obtained, the critical values off and modified I, as a practical guidelines, are proposed as 0.03 and 2.0, respectively.