• Title/Summary/Keyword: Soil Improvement

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Assessment of Agricultural Nutrient Surplus in Pig-concentrated Region in Korea

  • Lee, Yejin;Yun, Hong-Bae
    • Korean Journal of Soil Science and Fertilizer
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    • v.46 no.6
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    • pp.482-486
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    • 2013
  • Assessment of nutrient balance in region unit is important to make a decision on nutrient management in agriculture. In this study, the nutrient demand in arable land and nutrient supply from livestock manure and chemical fertilizer were estimated from pig-concentrated areas. Three regions (H, I and J) were selected on the basis of pig numbers per unit area of arable land. In H and I regions, nitrogen amount from pig manure occupied about 50% of total livestock manure. Nutrient supply was three times higher compared to the nutrient demand in each of 3 regions. Soil available phosphate of higher pig-populated area in regional unit was higher than less populated livestock area. Therefore, livestock manure-derived regional management and monitoring of soil nutrient contents is necessary for the minimization and improvement of nutrient surplus.

Evaluation on the Physical Characteristics of Cement-Type Solidification using Weathered Granite St Yellow Soil as an Aggregate (마사토, 황토를 골재로 이용한 시멘트계 고화재의 물리적 특성 평가)

  • 김특준;김인섭;이종규;추용식;김병익;김남호
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.601-606
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    • 2002
  • This study explored physical properties of a hardened cement and a concrete specimen using a high performance cement type solidification consisting of a weathered granite soil and a yellow soil mainly. Also the development of high performance cement type solidification was purposed for an intensity improvement and a long-term durability. As the experimental results, a mortar used by the weathered granite soil shows positive result, however using the yellow soil as a mortar Shows less positive result at the compressive strength. Also the dynamic modulus of elasticity measurement result, the concrete specimens used by the weathered granite and the yellow soil reached above 90%, so it seems to have the durability of freezing and thawing.

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A simplified procedure to incorporate soil non-linearity in missile penetration problems

  • Siddiqui, N.A.;Kumar, S.;Khan, M.A.;Abbas, H.
    • Structural Engineering and Mechanics
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    • v.23 no.3
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    • pp.249-262
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    • 2006
  • In this paper, a simplified mathematical procedure is presented to incorporate nonlinearity in soil material to predict the deceleration time history, penetration depth and other relevant parameters for normal impact of missiles into soil targets. Numerical method is employed for these predictions. The results of the study are compared with experimental observations and predictions available in the literature. A good agreement is found with experimental observations and an improvement is observed with existing predictions. A comparison is also made with linear soil model. Some parametric studies are also carried out to obtain the results of practical interest.

Study of Soil Nailing Application as a Reinforcement Method for Slided Slope (붕괴사면보강을 위한 Soil Nailing의 적용성에 관한 연구)

  • 이성철;김명학
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.127-134
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    • 2000
  • Soil nailing is in-situ ground improvement technique of reinforcing soils using passive inclusions for the purpose of slope stability. Also soil nailing, in general, was used and studied as a reinforcement technique at cut slope, but this paper presents the results of study for soil nailing application as a reinforcement technique at the banking over slided slope. In-situ pull-out tests of nails, instrumented with strain gauges, were performed to investigate the maximum pull-out load and to calculate the unit side resistance in each different layer. And the apparent average unit side resistance of this study was compared with that of other sites installed at cut slope.

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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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    • v.20 no.6
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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.

Professional Engineer Yard - The construction example of deep cement mixing method for the soil improvement of soft ground in sports center structure foundation work around the mouth of Nakdong River (기술사 마당 - 낙동강(洛東江)주변의 체육센터시설물기초 연약지반(軟弱地盤)처리를 위한 DCMM 시공사례)

  • Cho, Kyoo-Yung;Kim, Jin-Eok;Jeong, Byeong-Chan
    • Journal of the Korean Professional Engineers Association
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    • v.44 no.6
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    • pp.45-50
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    • 2011
  • As the Deep Cement Mixing Method is composed of drilled natural soft soil structure and injected cement slurry to be mix together in it, the nature of excavated ground is influenced directly to the application of constructability. Also the nature of in situ soil is the main material, the mix design and construction work plan should be established before the investigation of soil which is performed through the whole site confirm the soil parameter before construction. The nature of investigated soil and water level as should be performed accurately.

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Investigation of the liquefaction potential of fiber-reinforced sand

  • Sonmezer, Yetis Bulent
    • Geomechanics and Engineering
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    • v.18 no.5
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    • pp.503-513
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    • 2019
  • In the present, the liquefaction potential of fiber-reinforced sandy soils was investigated through the energy-based approach by conducting a series of strain-controlled cyclic simple shear tests. In the tests, the effects of the fiber properties, such as the fiber content, fiber length, relative density and effective stress, and the test parameters on sandy soil improvement were investigated. The results indicated that the fiber inclusion yields to higher cumulative liquefaction energy values compared to the unreinforced (plain) ground by increasing the number of cycles and shear strength needed for the liquefaction of the soil. This result reveals that the fiber inclusion increases the resistance of the soil to liquefaction. However, the increase in the fiber content was determined to be more effective on the test results compared to the fiber length. Furthermore, the increase in the relative density of the soil increases the efficiency of the fibers on soil strengthening.

Improvement Plan for Planting Large Trees in Artificial Ground of the Apartment Complex (공동주택 인공지반 대형교목 식재 개선방안)

  • Kang, Myung-Soo;Kim, Nam-Jung
    • Land and Housing Review
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    • v.6 no.4
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    • pp.221-229
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    • 2015
  • Large trees in the apartment complex are playing an important role to decide the quality of external environment. They are planted with the object of utilizing themselves as a landmark of the complex and enhancing space symbolism. Since planting large trees would require high maintenance costs and generate defect, it would cause decline in quality of external environment. This study researches on large trees in artificial ground of the apartment complex. This study analyzes actual condition of planting and tries to provide improvement direction of planting. In order to conduct this research, three target areas (over R30) and 265 trees are selected. Based on the drawings and specifications this study researches on the plan of landscape design, changes of field design, actual condition of completion, present condition of planting, minimum soil depth of growth and development and types of extra action for soil depth. The result shows that 85% of drawings and specifications for large trees in the apartment complex are deep-rooted tree species. On average large trees with R 35 are planted in artificial ground and there is lack of on average 65cm minimum soil depth of growth and development. Reviewing changes of field design is conducted in such limited size as mainly R30 and R40 and there is no extra plan for lack of soil depth. The plan for securing additional soil depth is done by 85% of mounding. However, since there is only 10% of satisfaction, the inappropriateness in securing additional soil is pointed out. This research also points out that the size of large trees, root characteristics and location-allocation for planting are pivotal factors for securing minimum soil depth of growth and development. This research also provides improvement direction in case of planning planting.

Characteristics and Improvement of Potential Acid Sulfate Soil Derived from Continental Materials on Alluvial Fan (선상지(扇床地) 육성(陸成) 잠재특이산성토(潛在特異酸性土)의 특성과 개량)

  • Jung, Yeun-Tae;Yun, Eul-Soo;Son, Il-Soo
    • Korean Journal of Soil Science and Fertilizer
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    • v.25 no.3
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    • pp.195-201
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    • 1992
  • A Potential acid sulfate soil derived from continental Holocene deposits on the fan-base was found and it was characterized with improvement practices. Artesian wells were scattered in the area, and the imperfectly drained soils were featured by having fine loamy with 7~30% of gravels. The potential acid sulfate soil layers were typified by having darkness in color with around 3.3~3.8% of O.M. and 0.34~0.41% of total sulfur. Soil pH ranged from 3.4 to 3.8 but it was decreased to 1.9~2.5 after oxidation with $H_2O_2$. Ground water sprang out from an artesian well contained a high amount of minerals such as Na, Ca, Mg, K, etc. and about 80ppm of sulfate which seemed to be responsible for pyrite formation. The soil was classified to member of "Fine loamy, mixed, acid, mesic, sulfic Haplaquepts" in taxonomically, and "weak potential acid sulfate soils" in interpretatively. The installation of tile drains with adding fine earth and liming were effective. However, the pH goes down to 4.8 again after 3 years of improvement practices.

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A Study on the Engineering Characteristics of the plaster-soil uiiitures (석고플라스터 혼합토의 공학적 특성)

  • 도덕현;정성모
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.27 no.4
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    • pp.53-60
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    • 1985
  • The plaster mixed to loam and sandy soil from 4 to 12 percent by dry soil weight, and the compaction, permeability, CBR, unconfined compressive strength and freezingthawing test were performed The results obtained are summarized as follows; 1.The coefficient of permeability reduced sharply at the plaster content of 4 percent, and in the CBR test, the swelling ratio reduced by the increment of plaster content. 2.The addition of plaster increased the unconfined compressive strength by the cementing effect, and it was found that the optimum plaster content, existed with the soil type, which showed the maximum strength 3.It was possible to enhance the unconfined compressive strength of the gypsum-lime-soil mixtures when the optimum content of plaster was mixed to the hydrated lime. 4.In case of sandy soil, the relative frost heave decreased with the mixture of plaster, however in loam soil, the relative frost heave began to increase at the plaster content of 12 percent than non-treated soil. Therefore the optimum plaster content existed for protecting frost heave by the different soil type. 5.The above summarized results make it possible to expect the effects such as improvement of soil properties, decrement of permeability, increment of unconfined compressive strength, and protection of frost heave, etc, therefore, it is considered that it is possible to it is plaster as sub-base materials of road.

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