• Title/Summary/Keyword: Silty soils

Search Result 214, Processing Time 0.026 seconds

The Prediction of Void Ratio in Unsaturated Soils (불포화토에서 공극비의 추정)

  • Lee Dal-Won
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.48 no.4
    • /
    • pp.51-57
    • /
    • 2006
  • This study was carried out to investigate the soil water characteristic curve and prediction of void ratio with net stress and matric suction using the linear elastic and volumetric deformation analysis method on unsaturated silty. The unsaturated soil tests were conducted using a modified oedometer cell and specimens were prepared at water content 2 times of liquid limit and required void ratio. The axis translation technique was used to create the desired matric suctions in the samples. It is shown that soil water characteristic curve and volumetric water content were affected significantly by preconsolidation pressure. As a matric suction increases, the reduction ratio of void ratio was shown to considerably small. Also, the predicted and measured void ratio for unsaturated soils using the linear elastic and volumetric deformation analysis showed good agreement as net stress and matric suction increases.

Study on the Salt Tolerance of Rice and other Crops in Reclaimed Soil Areas 15. The Effects of Salt on the Efficiency of Sunlight Utilization of Rice Canopy in Reclaimed Saline Soils (간척지에서 수도 및 기타 작물의 내염성에 관한 연구 15. 간척지에 재배한 수도 엽층의 수광 효과에 미치는 염분의 영향)

  • 임형빈
    • Journal of Plant Biology
    • /
    • v.14 no.3
    • /
    • pp.60-65
    • /
    • 1971
  • In order to observe the factors affecting light utilization efficiency in the canopy of a rice crop grown in reclaimed saline areas in Korea, 22 varieties of rice were cultured at the average salt concentration of 6.05mmhos/cm $25^{\circ}C$, (0.39%) in saline soils and non-saline silty loam soils. The inhibition of tillering ability by salt damage at the maximum tillering stage was greater than to growth in height. A significant direct correlation was observed between both ratios and salt concentration with each variety. In the salty areas the length of the flag leaf of the maturing stage showed a positive correlation with the production of rough rice while other living leaf showed a negative correlation. LAI of maturing stage was less in the salty area than in the non-salty area, while the former showed higher ratio in net assimilation and translocation to head with greater RGR before and after the heading stage.

  • PDF

Study on the Salt Tolerance of Rice and other Crops in Reclaimed Soil Areas 13. On the Absorption of the Mineral Elements of Rice and the Components of Rice Grains in Reclaimed Saline Soils (간척지에서 수도 및 기타작물의 내염성에 관한 연구 13. 간척지에서 수도의 무기양분 흡수와 쌀 성분에 관하여)

  • 임형빈
    • Journal of Plant Biology
    • /
    • v.14 no.1
    • /
    • pp.25-31
    • /
    • 1971
  • In order to observe the absorption pattern of mineral elements and the nutritional components of brown rice grown in reclaimed saline areas in Korea, the four commercial varieties of rice were cultured at the average salt concentration of 6.05 mmhos/cm, $25^{\circ}C$, (0.3%) in saline soils and non-saline silty loam soils. In the saline areas the absorptin of Na and Si was relatively high while the absorption of P, K and Ca was relatively low. N was absorbed actively before the emergence of the rice grains but showed relative decrease thereafter. There was no difference in Mg content. Though brown rice in the saline areas contained sugar abundantly with small contents of protein, fat and crude fiber. There was little difference in total carbollydrate and ash contonts.

  • PDF

Damping Characteristics of Solidified Soils Using Water-glass Chemical Grout (물유리계 약액(藥液)을 사용(使用)한 고결토(固結土)의 진동감쇠특성(振動減衰特性))

  • Chun, Byung Sik;Kwon, Yung In
    • KSCE Journal of Civil and Environmental Engineering Research
    • /
    • v.8 no.1
    • /
    • pp.141-150
    • /
    • 1988
  • Damping characteristics of chemically treated solls were studied by the use of FFT Analyzer and Bandwidth method. Also Modal Analysis was performed for the solidified silty sand samples. The soil samples were made of gravelly sand, sand, and silty sand, treated by water-glass chemical grouts. As the result of the study, it was found that the chemical grouting could be used for the vibration diminutinn effect as well as cut-off effect and strength improvement by the fact that the damping ratio of chemically treated soils was highly increased as the damping ratio of solidified soil was 0.11~0.22 and rathier high values in compare with the damping ratio of common soils which was 0.01~0.10.

  • PDF

Unsaturated Effective Stress Based on Water Retention Characteristics for Triaxial Tests of Silty Sand (실트질 사질토의 삼축시험 시 함수특성에 따른 불포화 유효응력)

  • Lee, Younghuy;Oh, Seboong;Baek, Seungcheol;Kim, Sangmin
    • Journal of the Korean GEO-environmental Society
    • /
    • v.14 no.1
    • /
    • pp.69-75
    • /
    • 2013
  • Suction stress is evaluated from soil water retention curves in order to deduce effective stress in unsaturated soils. $K_0$ consolidated triaxial tests were performed for silty sand to interpret effective stress in consolidation and shearing of unsaturated soils. Suction stresses from both consolidation stress and shear strength in triaxial tests were compared with those from soil water retention curves. The effective stresses on consolidation and shear strength are on each unique line, which are the same as that of the saturated case. It was found that the effective stress from soil water retention curves agrees with those from consolidation and shear strength in triaxial tests.

An Experimental Study on Silty Clay Subjected to Repeated Loads (반복하중을 받는 실트질 점토에 관한 실험적 연구 -과압밀 점토를 중심으로-)

  • Kim, Pal-Gyu;Kim, Gyeong-Jin;Song, Jeon-Seop
    • Geotechnical Engineering
    • /
    • v.5 no.4
    • /
    • pp.37-46
    • /
    • 1989
  • The object of this paper is to study the general characteristics of overconsolidated silty clays subjected to repeated loading. The samples are first remolded. overconsolidated and a series of strain - controlled triaxial repeated tests are carried out. Generally the relationship of deviator stress - axial strain of overconsolidated clay is similar in pattern to the normally consolidated clay under single load. But the behavior of the pore water pressure build up in the sample subjected to repeated loading is dependent upon the consolidation history and the level of repeated stress. Therefore through the series of the tests, the characteristics of stress -strain relationship of soils which are differentlly overconsolidated are investigated, analysed and then compared with each soils. And also, from the relationship of test results, the strength and strain characteristics of soils are obierved. The equilibrium lines which presents the critical repeated stress and equilibrium state in the sample under repeated loading, are often straight, but may be curved. And the tendency of the equilibrium lines is observed as to the variation of overconsolidation ratio.

  • PDF

Analysis of Half-life Time and Residual Concentration of Fungicide Iminoctadine Triacetate in Soils (토양에서 살균제 Iminoctadine Triacetate의 반감기와 잔류농도의 분석)

  • Oh, Hae-Bum;Kim, Il-Kwang;Jeong, Seung-ll;Lim, Bang-Hyun;Han, Sung-Soo;Choi, Yong-Hwa
    • Analytical Science and Technology
    • /
    • v.13 no.1
    • /
    • pp.34-40
    • /
    • 2000
  • The optimum conditions for the half-life time and residual analysis of the iminoactadine triacetate fungicide on soils were investigated by using the gas chromatography. Iminoctadine triacetate(IOTA) was extracted from soils with 2.0 M-NaOH/methanol and chloroform. The extracted IOTA was derivatized to pyrimidine hexafluroacetylacetone by the acetylation and analyzed with GC/ECD after elimination of moisture and impurities on the Sep-Pak column. From the standard addition experiments with 0.1 and 1.0 ppm, the average recoveries were ranged from 83.8 to 93.2 % and the detection limit was 0.005 ppm. The half-life time of iminoctadine triacetate in the silty clay was 30 days in the laboratory and 19.5 days in the field test whereas it was 27 days and 17.5 days for each in case of silty loam.

  • PDF

Dynamic Properties of Silty Sands at High Amplitude (Basic Properties) (Silt질 모래의 고변형률 진동특성(기본성질))

  • 송정락;김수일
    • Geotechnical Engineering
    • /
    • v.4 no.3
    • /
    • pp.27-34
    • /
    • 1988
  • Soils behave non-linearly at high strain. This study investigated the non-linear behavior of silty sands (Mixture of Ottawa Sand and Quartz Powder) by resonant column tests. The results were ·compared with Ramberg-Osgood's non-linear equation. From the tests, it was shown that the change of shear modulus and damping ratio was more sharp at low fine content, high void ratio and low confining pressure. It was also found that famberg-Osgood parameter, R was approximately 2.0, however the range of C varied from 200 to 3200.

  • PDF

Experimental Study on the Crop Cultivation Using Dredged Soil (준설토를 이용한 작물재배 시험연구)

  • 손재권;최진규;구자웅
    • Magazine of the Korean Society of Agricultural Engineers
    • /
    • v.40 no.2
    • /
    • pp.159-170
    • /
    • 1998
  • This study was initiated to investigate the applicability of the dredged soil from agricultural reservoirs on the crop cultivation. Four reservoirs were selected for this experiment, and properties of the dredged soils were analyzed physically and chemically. Soil textures were sandy loam(SL), silty loam(SiL), gravelly loam(GL), graveHy silty loam(GSiL), respectively. General chemical components, organic matter contents, main cations, heavy metals, etc. showed no adverse effects on crop growth. Tomato, cucumber, radish, Chinese cabbage were cultivated during 8 months period, in the soil treated with fertilizer and compost(Tmt.1), fertilizer(Tmt.2), compost(Tmt.3) and none (Tmt.4). Data for plant height, root zone depth and crop yield were collected and analyzed, and the yield for most crops showed increase as Tmt.1 >Tmt.2>Tmt.3>Tmt.4 by fertilizing methods, and as GL>GSiL>SL>SiL by soil textures. From the results, the crop cultivation using dredged soil was considered to be effective, due to its soil texture, organic matter content and fertilization.

  • PDF

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

  • Yoo, Nam-Jae;Kim, Kyum;Yoo, Chang-Sun
    • Journal of Industrial Technology
    • /
    • v.31 no.B
    • /
    • pp.91-98
    • /
    • 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.

  • PDF