• 제목/요약/키워드: soil strength

검색결과 2,034건 처리시간 0.031초

조립재가 흙의 역학적 성질에 미치는 영향 (Effect of Coarse mateflal on the mechanical properties of Soil)

  • 윤충섭;김호일
    • 한국농공학회지
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    • 제31권3호
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    • pp.57-69
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    • 1989
  • The study was carried out for the strength parameter of coarse grained Soil and slope stability analysis of earth dam. The test samples were taken fifteen kinds of soil from cohesive soil to coarse gravel. The degree of compaction of test samples for shear test and permeability test was chosen 95 percentage of maximum dry density. The results of this study are as follows ; 1.The maximum dry density(Yd) of coarse grained soil increase in proportion to coarse particles(P) with the relation of Y d= 1.609+0.0043P. 2.The coefficients of permeability(k) decrease by the increase of fine particles(n) with the relation of k=0.0426e-0 185n. 3.The cohesions of soil decrease by the increase of coarse particles, but internal friction angles are more increased in same condition. 4.The internal friction angles(${\Phi}$) decrease in inverse proportion to void ratio(e) with the relation of ${\Phi}$ = 73.068 - 69.268e. 5.The strength parameters( Ct ${\Phi}$t) by triaxial compression test are clearly smaller than that (Cd, ${\Phi}$d) by direct shear test in fine grained soil, but the differences between both parameters are a little in coarse grained soil.The relations of both parameters are as follows; Ct = O.544Cd + 0.04 ${\Phi}$t= 1.282${\Phi}$d-2306 6.In cohesive soil, the strength parameters( Cl ${\Phi}$l) by large size shear test apparatus are similar to the strength parameters(Cs , ${\Phi}$s) by small size shear test appratus, but Cs and ${\Phi}$s values are larger than Cl and ${\Phi}$l values from 10 percentage to 20 percentage in coarse grained soil. 7.The fine grained soil is inappropriate to high dam more than 20 meters and it must be taken coarse grained soil with high internal friction angle for high dam.

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Evaluation of unsaturated soil slope stability by incorporating soil-water characteristic curve

  • Zhai, Qian;Tian, Gang;Ye, Weimin;Rahardjo, Harianto;Dai, Guoliang;Wang, Shijun
    • Geomechanics and Engineering
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    • 제28권6호
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    • pp.637-644
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    • 2022
  • Loess soils are unsaturated and widely distributed in the northwest zone in China. Many steep slope of unsaturated are observed are observed to be naturally stable. However, a low factor of safety (FoS) for these slopes would be computed from the slope stability analysis following local code practices. It seems that the analyzed results following the local code practices do not agree with the real condition as observed in the field. It is commonly known that soil suction plays an important role in slope stability due to a higher shear strength of the unsaturated soil as compared with that of the saturated soil. In this paper, it is observed that the computed FoS can also be affected by unsaturated unit weight of the soil. However, the effect of unsaturated unit weight of the soil on the slope stability is commonly ignored in engineering practice. Therefore, both the effects of shear strength and unit weight of the unsaturated soil on the computed FoS of unsaturated soil slope are investigated in this study. It is observed that the unsaturated unit weight of soil on the computed FoS increases with increase in slope angle. It is also observed that the effects of the unsaturated shear strength and unsaturated unit weight on the computed FoS are more significant than the effect of 3D analyses compared to the 2D analyses on the FoS.

석회-시멘트 혼합토의 압축강도 및 내구 특성 (The Compressive Strength and Durability Characteristics of Lime-Cement-Soil Mixtures)

  • 오상은;연규석;김기성;김용성
    • 한국농공학회논문집
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    • 제54권1호
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    • pp.83-91
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    • 2012
  • In this study, the compressive strength characteristics of lime-cement-soil mixtures, composed of lime, soil, and a small amount of cement, were investigated by performing the unconfined compression tests, the freezing and thawing tests, the wetting and drying tests and the permeability tests. The specimens were made by mixing soils with cement and lime. The cement contents were 0, 6, 8 and 10 %, and the lime contents were 2, 4, 5, 10, 15 and 20 % in weight. Each specimen was cured at constant temperature in a humidity room for 3, 7 and 28 days. The compressive strength characteristics of the lime-cement-soil mixtures were then investigated using the unconfined compression tests, freezing and thawing tests and the wetting and drying tests. Based on the test results, a discussion was made on the applicability of the lime-cement-soil mixtures as a construction material.

실험적 연구를 통한 모래입자 형상이 토질정수에 미치는 영향 (Experimental Study on Effects of Sand Particles Shape on Geotechnical Properties)

  • 신은철;김종인;이한진
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2006년도 춘계 학술발표회 논문집
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    • pp.896-905
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    • 2006
  • Several soil parameters such as particle characteristics, geological element, drainage and loading conditions are influenced on the shear strength of soil. The characteristics of soil particles are important factor to the shear strength of soil. However, this component is not well considered in the determination of soil strength in Korea. The particle shape of sand was analyzed by utilizing SEM(Scanning Electron Micrograph) and compared its results in terms of aspect ratio, angularity and roughness. Based on the determined soil parameters, the ultimate bearing capacity of sandy ground was estimated by using Terzaghi bearing capacity equation.

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보강토옹벽의 사고사례에 관한 연구 (Reinforced Earth Retaining Wall of The Collapsed-A Case Study.)

  • 유충식;정혁상;이성우
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2004년도 춘계학술발표회
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    • pp.958-967
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    • 2004
  • This paper deal with cause and analysis about case of collapsed reinforced-soil retaining wall. The analysis of the cause was carried through experimentation, slop stability analysis and literature study. The experimentation treated the large direct shear test, the hydraulic conductivity test and the other basic test through backfill extracted from collapsed reinforced-soil retaining wall. The ultimate tensile strength was established by rib tensile strength test of geogrid. The analysis of internal and external stability of reinforced-soil retaining wall was performed on the basis of parameters. The result of analysis, reinforced-soil retaining wall and the slope at the dry season are stable. However, the factors that fine-grained soil at hydrometer test exceed the standard of the design, rainfall duration is too long at the time of collapse and monthly pricipitation is heavy are cause of the collapse.

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Strengthening of cement blended soft clay with nano-silica particles

  • Thomas, Geethu;Rangaswamy, Kodi
    • Geomechanics and Engineering
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    • 제20권6호
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    • pp.505-516
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    • 2020
  • In recent years, Nano-technology significantly invaded the field of Geotechnical engineering, particularly in soil stabilisation techniques. Stabilisation of weak soil is envisioned to modify various soil characteristics by the addition of natural or synthetic materials into the virgin soil. In the present study, laboratory experiments were executed to investigate the influence of nano-silica particles in the consistency limits, compressive strength of the soft clay blended with cement. The results revealed that the high compressibility behaviour of soft clay modified to medium-stiff condition with fewer dosages of cement and nano-silica. The mechanism behind the strength development is verified with the previous researches as well as from Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction test (XRD) and Scanning Electron Microscopy (SEM) analysis. Based on the results, the presence of nano-silica in soft clay blended with cement has a positive effect on the behaviour of soil. This technique proves to be very economical and less detrimental to the environment.

폐타이어 분말 및 시멘트를 혼합한 동결토의 특성 (The Property of Frozen Soil Mixed with Shredded Tire and Cement)

  • 김영진;손승모
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1487-1493
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    • 2008
  • The frost heaving is related with thermal conduction rate and permeability. If the thermal conduction rate can be controlled, it is effective to prevent from frost heaving. If soil mixed with shredded tire which has relatively lower thermal conduction rate than soil, it helps preventing from frost heaving. However, in this case, the shear strength can get weak. In this study, we compared thermal conduction rate of soil and shredded tire, and test uniaxial compression strength of soil which is mixed with shredded tire and cement in different ratio.

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마사토 미립분을 활용한 친환경 흙 콘크리트 개발에 관한 기초적 연구 (A Fundamental Study on the Development of Eco-Friendly Soil Concrete Using Decomposed granite soil Particles)

  • 홍성준;박동천;류동우
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2021년도 봄 학술논문 발표대회
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    • pp.116-117
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    • 2021
  • This study examined basic mechanical properties by developing eco-friendly soil concrete using Masato particulate matter treated as waste. Experiments show that DG10 satisfies the compressive strength criterion, but for DG20, the criterion was not reached. As the mixing volume of Masato particulates increased, the compressive strength and slump decreased, and in the case of the compression strength test after freezing and melting, it was found that the standards were not met.

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Shear strength characteristics of a compacted soil under infiltration conditions

  • Rahardjo, H.;Meilani, I.;Leong, E.C.;Rezaur, R.B.
    • Geomechanics and Engineering
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    • 제1권1호
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    • pp.35-52
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    • 2009
  • A significantly thick zone of steep slopes is commonly encountered above groundwater table and the soils within this zone are unsaturated with negative pore-water pressures (i.e., matric suction). Matric suction contributes significantly to the shear strength of soil and to the factor of safety of unsaturated slopes. However, infiltration during rainfall increases the pore-water pressure in soil resulting in a decrease in the matric suction and the shear strength of the soil. As a result, rainfall infiltration may eventually trigger a slope failure. Therefore, understanding of shear strength characteristics of saturated and unsaturated soils under shearing-infiltration (SI) conditions have direct implications in assessment of slope stability under rainfall conditions. This paper presents results from a series of consolidated drained (CD) and shearing-infiltration (SI) tests. Results show that the failure envelope obtained from the shearing-infiltration tests is independent of the infiltration rate. Failure envelopes obtained from CD and SI tests appear to be similar. For practical purposes the shear strength parameters from the CD tests can be used in stability analyses of slopes under rainfall conditions. The SI tests might be performed to obtain more conservative shear strength parameters and to study the pore-water pressure changes during infiltration.

모래의 파쇄성과 단입자강도 특성에 관한 기초적 연구 (A Basic Study on Crushability of Sands and Characteristics of Particle Strength)

  • 곽정민
    • 한국지반공학회논문집
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    • 제15권5호
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    • pp.193-204
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    • 1999
  • 흙의 파쇄성과 관련된 지반공학적 문제에 있어서 입상재료의 강도-변형특성을 해명하기 위한 중요한 인자의 하나로 흙입자의 파쇄를 들 수 있다. 최근, 열대ㆍ아열대 지방의 해안을 중심으로 거대한 해양 유전개발이 진행되고 있으며 이 지역에 넓게 분포된 카보네이트계 모래의 거동이 기존의 실리카계 모래의 거동에 비해 두드러지게 다르다는 것이 현장에서의 문제로 대두되고 있다. 본 연구에서는 흙의 파쇄성과 연관지어 입상재료의 역학특성을 정립하는 첫 단계로서, 흙 입자파쇄의 기본이 되는 개별입자의 파쇄 강도특성을 명백히 하기 위하여 4종류의 서로 다른 모래를 이용하여 단입자 파쇄시험을 수행하였다. 단입자 파쇄강도는 모래의 입자형상, 광물성분 및 입경의 영향을 고려하였으며, 입도분포 곡선의 $D_{50}$에 대응하는 흙입자 강도는 카보네이트성분의 함유량이 많을수록, 입자형상이 뾰족할수록 작은 값을 나타냈다.

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