• Title/Summary/Keyword: soil resistance

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Study on the Effect of SBR Latex on the Properties of Soil Pavement (SBR Latex를 이용한 흙 포장의 재료특성 연구)

  • Lee, Sang Yum;Hwang, Sung Do;Yang, Sung Lin
    • International Journal of Highway Engineering
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    • v.16 no.5
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    • pp.73-82
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    • 2014
  • PURPOSES : The purpose of this study is to determine the optimum addition rate of SBR latex through the evaluation of durability and strength of SBR latex applied soil pavement. Formerly used materials such as fly ash and cement in soil pavement had resulted in decreased durability due to micro crack by heat of hydration and shrinkage crack in winter. However, that agglutinated polymers help adhesion to aggregate increased comes up with preventing the crack opening when the number of capillary tubes of SBR latex get decreased in the hydration process of cement. Therefore, in this study, it is suggested that the evaluation of the field applicability of soil pavement be conducted through the performance lab test in terms of strength increment, adhesion improvement, and crack resistance based on SBR latex addition rate. METHODS : In order to evaluate the field applicability of soil pavement, SBR latex was added 0 to 3% by 1% increment, with fixed cement contents of 3% and 5%. The resistance of shear failure and crack of soil pavement were evaluated by performing the uniaxial compressive strength test and indirect tensile strength test at -20 and $20^{\circ}C$, respectively. RESULTSCONCLUSIONS : It was found out that from both tests, resistance of shear failure and crack were improved with increment of curing time, and especially more than 2% of SBR latex addition rate and 5% cement content gave better results.

The Effect of Shear Resistance in Rigid Soil-nailed Slope System (강성 쏘일네일 보강 사면의 전단저항 효과)

  • Kwon, Young-Ki;Jeong, Sang-Seom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.6C
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    • pp.295-301
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    • 2009
  • In general the stability of soil nail-slope system, the shear resistance is neglected because the tensile resistance of nail acts mainly for slope stabilization. This is because that deformed steel is generally used for nail and it does ductile behavior. In other side when the steel pipe with high rigidity is used for nail, the shear resistance at failure surface work more than deformed steel. In order to analyze effects of shear resistance at the soil nail-slope system with high steel piped nail, a series of numerical analyses were performed. Also numerical analyses at 3 conditions - 5 nailed, 7 nailed, 9 nailed at the same slope were perfomed for investigating the trend of shear resistance effect. From these 3D numerical analyses, it was found that the maximum shear resistances at each nails were larger in case of steel piped nail and because of this, the factor of safety at the condition of the steel piped nail appears larger than that of deformed steel nail.

Soil Resistant and Blood Repellent Finishes of Nonwoven Fabrics Using Foam (거품을 이용한 부직포의 방오방혈가공)

  • 이정민;배기서;노덕길;전병열
    • Textile Coloration and Finishing
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    • v.4 no.3
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    • pp.74-81
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    • 1992
  • Chemical bonded nonwoven fabric for apparel use and spunlaced nonwoven fabric for medical use were finished for soil resistance and blood replellency with fluorochemicals utilizing foam finishing technology (FFT) and conventional padding application techniques. The FFT process improved soil and abrasion resistance properties of nonwoven fabrics compared with the conventional padding process. Excellent water-oil-saline-alcohol repellency values and water impact penetration values were obtained in the spunlaced nonwoven fabrics with both techniques.

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Discharge Capacity of PBD and Deep Soft Soil Improvement (PBD의 배수특성과 대심도 지반개량)

  • 구본효
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.585-592
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    • 2002
  • Discharge capacity of PBD is the most important factor of specification items to control any product of PBD. There is no standard specification for the PBD. Because the degree of discharge capacity is related to well resistance, install depth, maximum strain etc in the field. Discharge capacity test of PBD, permeability test of filter are conducted using PBD materials used in Korea. This paper proposes the critical discharge capacity for deep PBD under condition of non well resistance based upon their test and theoretical calculation. It was found that discharge capacity more than about 10 ㎤/sec is enough to undergo designing of deep PBD without well resistance.

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Effects of Lift Resistance on Dynamic Load Acting on a Circular Wheel

  • Kishimoto, Tadashi;Taniguchi, Tetsuji;Sakai, Jun;Choe, Jung-Seob;Ohtomo, Koh-Ichi
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 1993.10a
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    • pp.1166-1175
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    • 1993
  • The objective of this study is to measure contra-retractive adhesion and lift resistance acting on the rim section of a circular wheel for analyses of their effects on the dynamic load. A circular iron wheel was used for experiments. A part of the wheel rim was cut off, and transducers which can measure normal and tangential forces were installed in this section. Experiments were conducted on a laboratory soil bin which was filled with clayey soil under wet and dry conditions. The mechanism of generating contra -retractive adhesion on a circular wheel were analyzed by the experiments and motion analyses of the wheel. Effects of lift resistance on dynamic load were analyzed by measured forces under wet soil conditions in comparison in comparison with those under dry conditions. The showed that a part of the lift resistance were transferred to the dynamic load. These results may become basic data and ideas for analyses of tractor dynamic under wet soil conditions.

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Effects of Maximum Probe Spacing of Soil Resistivity Survery on Substation Grounding Analysis (변전소 접지설계를 위한 대지저항율 측정시 전극간 최대간격이 접지해석에 미치는 영향)

  • 정길조;곽희로;최종기
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.8
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    • pp.382-386
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    • 2001
  • Presently, typical maximum probe spacing of soil resistivity survey(Wenners 4 pin method) is 20 m in case of 154 K substation grounding design of KEPCO. This paper examined the effects of maximum probe spacing of wenner method on the equivalent soil modeling and the accuracy of grounding resistance measurement by comparing the calculated FOP(Fall-of-Potential) curves of various soil models with the measured one at 154kV H substation. The comparison results showed that the inaccurate estimation of deep soil resistivity, which is caused from the short probe spacing of soil resistivity survey, can produce large errors on measurement of grounding resistance. In this paper a quantitative analysis of FOP at H substation has been presented.

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Characteristics of Impulse Discharges in Wet Soil (습한 토양의 임펄스방전특성)

  • Kim, Hoe-Gu;Lee, Bok-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.363-369
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    • 2017
  • This paper presents the experimental results related to soil ionization and electrical breakdown in a concentric hemispherical electrode system under lightning impulse voltages. Dynamic voltage-current and impedance-time characteristics of soil ionization were measured and analyzed. Also the electrical breakdowns of the soil gap were investigated. The time-lag to the peak current corresponds to the soil ionization propagation. The time of ionization propagation in wet sand is found to decrease with increasing the impulse currents. A drastic decrease in ground resistance was observed during the impulse current spreading in sand. The electrical breakdown appears at the wave tail of impulse voltage and results in a wide scatter in V-t curves. The voltage-current curves have a fan-like shape attributed to ionization processes which result in increasing current and decreasing voltage.

Study on small resistance regions in post-liquefaction shear deformation based on soil's compressive properties

  • Jongkwan Kim;Jin-Tae Han;Mintaek Yoo
    • Geomechanics and Engineering
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    • v.36 no.3
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    • pp.295-301
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    • 2024
  • Understanding the post-liquefaction shear behavior is crucial for predicting and assessing the damage, such as lateral flow, caused by liquefaction. Most studies have focused on the behavior until liquefaction occurs. In this study, we performed undrained multi-stage tests on clean sand, sand-silt mixtures, and silty soils to investigate post-liquefaction shear strain based on soil compressibility. The results confirmed that it is necessary to consider the soil compressibility and the shape of soil particles to understand the post-liquefaction shear strain characteristics. Based on this, an index reflecting soil compressibility and particle shape was derived, and the results showed a high correlation with post-liquefaction small resistance characteristic regardless of soil type and fine particle content.

Derivation of Optimum Operating Conditions for Electrical Resistance Heating to Enhance the Flushing Effect of Heavy Oil Contaminated Soil (중질유 오염토양의 세정효과를 증진시키기 위한 전기저항가열의 최적 운전조건 도출)

  • Lee, Hwan;Jung, Jaeyun;Kang, Doore;Lee, Cheolhyo
    • Journal of Environmental Impact Assessment
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    • v.29 no.3
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    • pp.219-229
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    • 2020
  • This study evaluated the applicability of the convergence technology by deriving the optimum conditions about operating factors of electrical resistance heating to enhance the soil flushing effect on soil contaminated with bunker C oil in the coastal landfill area. As a result of the batch scale experiment, the flushing efficiency of the VG-2020 was higherthan that of the Tween-80, and the flushing efficiency increased by about 1.4 times at 60℃ compared to room temperature. As a result of the electrical resistance heating box experiment, soil temperature rose to 100℃ in about 40~80 minutes in soil with water content of 20~40%, and it was found that the heat transfer efficiency is excellent when the pipe-shaped electrode rod with STS 316 material is located in a triangular arrangement in saturated soil. In addition, it was confirmed that the interval between the electrode rods to maintain the soil temperature above 60℃ under the optimum conditions was 1.5 m, and the soil flushing box experiment accompanying electrical resistance heating showed TPH reduction efficiency of about 55% at 5 Pore Volume, and satisfied the Korean standard for the conservation of soil (less than TPH 2,000 mg/kg) at 10 Pore Volume.

Three-Dimensional Subsurface Resistivity Profile using Electrical Resistance Tomography for Designing Grounding Grid (접지 그리드 설계를 위한 전기 저항 단층촬영법에 기반한 지표의 3차원 저항률 분포 추정)

  • Khambampati, Anil Kumar;Kim, Kyung Youn
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.4
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    • pp.117-128
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    • 2016
  • Installation of earth grounding system is essential to ensure personnel safety and correct operation of electrical equipment. Earth parameters, especially, soil resistivity has to be determined in designing an efficient earth grounding system. The most common applied technique to measure soil resistance is Wenner four-point method. Implementation of this method is expensive, time consuming and cumbersome as large set of measurements with variable electrode spacing are required to obtain a one dimensional resistivity plot. It is advantageous to have a method which is of low cost and provides fast measurements. In this perspective, electrical resistance tomography (ERT) is applied to estimate subsurface resistivity profile. Electrical resistance tomograms characterize the soil resistivity distribution based on the measurements from electrodes placed in the region of interest. The nonlinear ill-posed inverse problem is solved using iterated Gauss-Newton method with Tikhonov regularization. Through extensive numerical simulations, it is found that ERT offers promising performance in estimating the three-dimensional soil resistivity distribution.