• 제목/요약/키워드: Silty soil

검색결과 386건 처리시간 0.02초

유기질층을 포함한 고소성 실트질 연약지반의 침하 예측 (Prediction of Settlement for the Highly Plastic and Silty Soft Ground Contained of the Organic Deposits)

  • 유남재;김겸;유창선
    • 산업기술연구
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    • 제31권B호
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    • pp.91-98
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    • 2011
  • In this thesis, from the results of settlement measurement performed at the site where embankment earthwork was carried out on the ground consisting of highly plastic and silty soft soils interlayered with organic deposits, various methods of predicting the embankment settlement such as Hoshino's method, Asaoka's method, hyperbolic method, ${\sqrt{s}}$ method and Monden's method were used to investigate their applicability and the inverse method of finding the soil parameter related to consolidation was used to predict the consolidation behavior in the future. It was confirmed that reliable prediction of consolidation behavior under various conditions could be done to estimate soil parameter related to consolidation such as the consolidation index and consolidation coefficient by the inverse method of comparing the measured settlement with the predicted value by the settlement prediction methods.

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자연지질매체를 이용한 PCE로 오염된 지하수 정화 (The effect of permeable geobarrier using gravel bean and silty clay for remediation of PCE contaminated groundwater)

  • 이달희;전이원;장호완;이종열;서형기
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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    • pp.110-113
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    • 2005
  • The objective of this study was to examine the effect of proposed permeable eobarrier system for removal of PCE from groundwater. The materials used for the natural geobarrier are gravel bean and silty clay. In addition, the effect of Pyeongtaek soil on PRB assessed in this experiments. It was observed that the adsorption of PCE in natural geobarrier system is eligible for real site. However, natural geobarrier system has various factors based on using materials. Therefore, more laboratory work is needed to study about permeable geobarrier.

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The behaviors of a Korean weathered soil under monotonic loadings

  • Sangseom Jeong;Junyoung Ko;Sumin Song;Jaehong Kim
    • Geomechanics and Engineering
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    • 제38권2호
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    • pp.157-164
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    • 2024
  • This paper describes the general trends of the stress-strain behavior of Korean weathered soil prior to failure and behavior at failure under triaxial loading. The isotropically consolidated samples were tested in a testing device under monotonic undrained loading. Relative density, effective mean pressure and fine content were the factors varied in the experimental investigation. The test results were analyzed and their behaviors were interpreted within the framework of plasticity constitutive model for a weathered Korean silty sand. Possible physical bases for the proposed forms are discussed. Validation of the applied model using the laboratory results is also given.

부곡통의 분류 (Taxonomical Classification of Bugog Series)

  • 송관철;현병근;손연규;홍석영;김이현;최은영
    • 한국토양비료학회지
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    • 제42권6호
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    • pp.472-477
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    • 2009
  • Alfisols로 분류되고 있는 부곡통을 재분류하기 위하여 부곡통 대표단면의 형태적 특성을 조사하고, Soil Taxonomy의 표 준 분 석 방 법 인 Soil Survey Laboratory Methods Manual에 따라서 토양을 분석하여 laboratory data sheets를 작성하였다. Ap층 (0~22 cm)은 진갈색 (7.5YR 4/6)의 양토이고, BAt층 (22~41 cm)은 갈색 (7.5YR 4/4)의 식양토, Bt1층 (41~59 cm)은 진갈색 (7.5YR 4/6)의 미사 질식양토, Bt2층 (59~78 cm)은 진갈색 (7.5YR 4/6)의 미사질식양토, Btx1층 (78~90 cm)은 진갈색 (7.5YR 4/6)의 미사질식양토, Btx2층 (90~160 cm)은 갈색 (7.5YR 4/4)의 미사질식양토이다. 부곡통은 화강편마암, 화강암, 또는 편암지대의 충적붕적층을 모재로 하는 토양으로 약한 경사지에 분포하며, 대부분 밭으로 이용되고 있다. Ap층 (0~22 cm)은 ochric 감식표층, BAt층에서 Btx2층 (22~160 cm)까지는 점토집적층인 argillic층을 보유하고, 78~160 cm 깊이에 fragipan을 보유하고 있다. 기준깊이인 fragipan 상부 경계 아래 75 cm 깊이인 153 cm 깊이에서의 염기포화도 (양이온 합)가 35.0% 미만으로 낮다. 따라서 부곡통은 Alfisols이 아니라 Ultisols로 분류되어야 한다. Udic 토양수분상을 보유하고 있으므로 부곡통은 Udults 아목으로 분류될 수 있다. 무기질 토양표면으로부터 100 cm 이내 깊이에 fragipan을 보유하고 있으므로 Fragiudults 대군의 분류기준을 충족시키고 있다. 우리나라 토양으로는 처음으로 보고되는 Fragiudults이다. 부곡통은 Fragiudalfs의 전형적인 특성을 나타내므로 아군은 Typic Fragiudults로 분류된다. 토성속 제어부 위에서의 토성속이 fine silty이고, mesic 토양온도상을 보유한다. 따라서 부곡통은 Fine loamy, mixed, mesic family of Typic Fragiudalfs가 아니라 Fine silty, mixed, mesic family of Typic Fragiudults로 분류되어야 한다.

Influencing of drying-wetting cycles on mechanical behaviors of silty clay with different initial moisture content

  • Shi-lin Luo;Da Huang;Jian-bing Peng;Fei Liu;Xiao-ran Gao;Roberto Tomas
    • Geomechanics and Engineering
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    • 제38권3호
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    • pp.307-317
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    • 2024
  • To get a better understanding of the effect of drying-wetting cycles (DWC) on the mechanical behaviors of silty clay hiving different initial moisture content (IMC), the direct shear tests were performed on sliding band soil taken from a reservoirinduced landslide at the Three Gorges Reservoir area. The results indicated that, as the increasing number of DWC, the shear stress-displacement curves type changed from strain-hardening to strain-softening, and both the soil peak strengths and strength parameters reduced first and then nearly remain unchanged after a certain number of DWC. The effects of DWC on the cohesion were predominated that on the internal friction angle. The IMC of 17% is regarding as the critical moisture content, and the evolution laws of both peak shear strength and strength parameters presented a reversed 'U' type with the rising of the IMC. Based on it, a strength deterioration evolution model incorporating the influence of IMC and DWC was developed to describe the total degradation degree and degradation rate of strength parameters, and the degradation of strength parameters caused by DWC could be counterbalanced to some extent as the soil IMC close to critical moisture content. The microscopic mechanism for the soil strength caused by the IMC and DWC were discussed separately. The research results are of great significance for further understanding the water-weakening mechanicals of the silty clay subjected to the water absorption/desorption.

반목하중으로 인한 지반의 변형 예측 (Approximate Prediction of Soil Deformation Caused by Repeated Loading)

  • 도덕현
    • 한국농공학회지
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    • 제30권3호
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    • pp.69-81
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    • 1988
  • The Repeated Load Triaxial and Oedometer Tests to the weathered granite & silty clay soil have been fulfilled to investigate their dynarnic characteristics. The results obtained are summarized as follows ; 1. In the relation between the repeated triaxial compression and the oedometer test, the recoverable strain of weathered granite soil showed a tendency to decrease by the increase of the repeated loads number(N), and that of silty clay showed approximately constant values while the total strain increased continuously. 2. The changes of plastic strain was dependent to the level of deviator stress which is the most important element in the calculation of soil deformation under repeated load condition. And there was a significance of 10% between the level of stress and plastic strain. 3. When the soil was aimost dried or saturated to 100%, the deformation by the repeated loads was small. However the deformation showed peak around the saturation of 50%. 4. When the deformation was predicted by the repeated triaxial load tests of a laboratory, it is desirable to introduce the threshold stress concept in the calculation of deformation of subgrade of the pavement. 5. The improved design equation (Eq. 16) introducing the modulus of conversion(Fo), which is based on the Boussineq' s theory, is considered to be rational in the design of flexible pavement. From the above results, the deformation to the repeated traffic loads could be predicted by the repeated triaxial tests on the pavement materials or undisturbed soil layers, therefore it is think that the durable and econornic pavement could be constructed by reflecting that to the design.

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실트질 모래지반의 비선형 거동특성 분석 (Analysis of Non-Linear Behavior in Silty Sand)

  • 이경숙;김현주;이준환
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 춘계 학술발표회 논문집
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    • pp.1159-1166
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    • 2005
  • In the present study, a series of laboratory tests with sands of different silt contents, are conducted and methods to assess non-linear behaviors based on in-situ test results are proposed. Modified hyperbolic stress-strain model is used to analyze non-linearity of silty sands in terms of non-linear degradation parameters f and g as a function of silt contents and relative density $D_R$. Stress-strain relationship results were obtained from a series of triaxial tests on sands containing different amounts of silt. Initial shear modulus which was applied to normalize modulus degradation of silty sands were determined based on the resonant column test results. From the laboratory test results, it was observed that, as the relative density increases, values of f decrease and those of g increase. Cone resistance $q_c$ for silty soil condition used in the triaxial tests were estimated based on the cavity expansion analysis. A suggestion to make an estimation of degradation parameters f and g as a function of fine contents is addressed in terms of cone resistance $q_c$ .

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Effects of Soil Moisture on the Growth of American Ginseng (Panax quinquefolium L.)

  • Li, Thomas S.C.;Berard, R.G.
    • Journal of Ginseng Research
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    • 제22권2호
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    • pp.122-125
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    • 1998
  • Adequate available soil moisture level is considered to be one the most important components in growing high yields of good quality ginseng. Excessive soil moisture may promote stillborn fungal pathogens and cause serious diseases in ginseng fields. This study showed that soil moisture levels for optimum growth and health of ginseng varied with soil texture. Fifty- percent available moisture for sandy loam and 75% for silty loam are the best moisture levels for good growth and higher yield.

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토양과 수위 및 차광의 차이가 창포(Acorus calamus var. angustatus)의 생육에 미치는 영향 (Effects of Soil, Water Level and Shading on Growth of Acorus calamus var. angustatus)

  • 신승훈;김민수;김윤하
    • 한국조경학회지
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    • 제32권5호
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    • pp.63-72
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    • 2004
  • This study was carried out to analyze effects of soil, water level and shading on growth of sweet flag(Acorus calamus var. angustatus). Three types of soil were used, which included sandy, silty loam and paddy loam soil. Three levels of shading were applied in the experiment: no shading, 55% shading and 75% shading. The water levels were also adjusted to three levels in the experiment. The results are summarized as follows; 1. The cultivation of sweet flag in sandy soil with low water level resulted in decreased fresh weight compared to that at planting. This result indicates that the water level should be maintained higher than the soil surface for sweet flag growth in sandy soil. 2. 5 out of 72 sweet flags died in paddy loam soil. Water saturation of soil easily reduced paddy loam soil, and root growth of sweet flags in reduced soil condition were restricted, resulting in the dead plants. 3. The growth of sweet flag in paddy loam soil was worse than those in silty loam, indicating that reduced soil conditions in paddy loam is harmful to root growth. In planting sweet flags in paddy loam, improved soil aeration in paddy loam soil is necessary for good growth of sweet flag. 4. The maintaining of high water levels is better than that of low water levels in sweet flag cultivation. During winter, soil near the water surface froze and sweet flags in frozen soil were stressed physiologically. Maintaining high water levels prevents soil from being frozen which is good for the growth of sweet flags. 5. There was not significant difference in the growth of the sweet flag between non-shading and 55% shading. It thus appears that sweet flags can grow soundly under shading rate lower than 55%.

저소성 실트질흙의 흙 시멘트에 관한 연구 (A Study on the Cement Mixture With Low Plasticity Silty Soil)

  • 김주범;박완순류기송김성교
    • 한국농공학회지
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    • 제17권2호
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    • pp.3778-3783
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    • 1975
  • The objective of this study is to determine an appropriate cement of soil-cement in which silty soil of salty tidal flat with low plasticity was used. Physical, chemical and mechanical tests were conducted to find out the standard properties of the soil to be used. Various cement contents used in this test were 8%, 10%, 12%, and 14%, and the compressive strength was tested after 7 days and 28 days of standard curing in the above each cement content respectively. The results obtaind are summarized as follows. 1. As the cement content was increased from 8% to 14%, Maximum dry density (M.D.D.) and optimum moisture content (O.M.C.) were not changed remarkably. 2. Density of soil-cement was directly proportional to cement content and inversely proportional to water content. 3. OMC was generally decreased in proportion to the increase of cement content. 4. Compressive stranth was directly proportional to centent and inversely proportional to water content. 5. In freezing and thawing test, maximum loss of 10% in the total Weight was found on the 8% cement mixture. and This loss was rapidly decreased to 2% when the Cement content of the mixture was more than 10%.

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