• Title/Summary/Keyword: 노상

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A Study on the Structural Design of Permeable Asphalt Pavement (투수성 아스팔트포장 구조설계방법에 관한 연구)

  • Lee, Soo-Hyung;Yoo, In-Kyoon;Kim, Je-Won
    • International Journal of Highway Engineering
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    • v.13 no.3
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    • pp.39-49
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    • 2011
  • The porous pavement system is widely considered very effective in urban street because of its various benefits on safety and environment, but the pavement thickness design system has not been established yet. In porous pavement system. rainwater penetrates to the subgrade through porous pavements layers. Porous pavements are expected to reduce or alleviate the problems caused by impermeable pavement layer such as flood damage due to heavy rain in the city, drainage load, disorder in ecosystem, and heat island. However, its structural design methods in traffic roads has not been made mainly because of not being able to consider adequately the effect of rainwater on subgrade strength. In this study, structural design method of porous pavements is suggested after considering the subgrade weakness due to rainwater and numerical mechanical analysis. It is noted that elastic modulus of subgrade is reduced by 20% as subgrade moisture content is increased by 2% at optimum moisture content in the literature review. As a result of both finite element analysis and strength loss of subgrade by the existing design method, it is necessary to increase subbase thickness about 30cm in porous pavements compared with the existing traffic road pavement system. It is similar to premium thickness of structural design of porous pavements in Japan.

Application of The Dynamic Cone Penetrometer for Strength Estimation of Pavement Foundation (현장에서의 동적관입시험을 이용한 노상토의 지지력 평가연구)

  • An, Ji-Hwan;Yang, Sung-Lin;Park, Hee-Mun;Kwon, Su-Ahn
    • International Journal of Highway Engineering
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    • v.6 no.3 s.21
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    • pp.17-26
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    • 2004
  • The in-situ California Bearing Ratio (CBR) test has been widely used for evaluating the subgrade condition in asphalt concrete pavements. However, because the in-situ CBR test is expensive and takes plenty of time for operation, it is very difficult to figure out the in-situ characteristics of subgrade strength in detail. For faster and economical operation, the Dynamic Cone Penetrometer (DCP) has been often utilized for estimating the subgrade strength in the field. The relationship between the CBR value and DCP index obtained from the DCP testing has been studied using the laboratory and in-situ testing by other foreign researchers. The objective of this study is to determine the relationship between in-situ CBR value and DCP index of the subgrade materials used in Korea. The DCP index for evaluating the strength of subgrade materials produced in Korea is presented in this paper. Research results propose the regression equation to explain the relationship between the CBR and DCP tests. The in-situ CBR values of subgrade materials range from 20 to 45% indicating the good and sound subgrade condition.

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INVESTIGATION OF SUBSURFACE CAVITIES UNDER PAVEMENT STRUCTURES WITH DYNAMIC CONE PENETROMETER TESTS (동적관입시험(DCP TESTS)에 의한 포장체 하부구조내 공동(空洞)현상에 관한 조사)

  • 김종렬
    • Journal of Korean Society of Transportation
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    • v.16 no.2
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    • pp.99-105
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    • 1998
  • 이 논문은 포장체 하부구조내 공동(空洞)현상에 대한 위치를 규명하는데 있어서 신속하면서, 간단하고 신뢰성있는 방법을 제시하고자 한다. 동적관입시험(DCP)을 사용하여 콘크리트 슬라브하부의 노상토에 대한 강도를 측정하였다. 타격회수에 대한 침하의 양으로 측정되는 동적관입침하율을 비교하여 포장체하부의 연약지반에 대한 위치를 규명하였다. 콘크리트 포장체 하부의 공동(空洞)현상 및 연약화된 노상토에 대한 정보를 얻고자 하는 엔지니어를 위하여 시험방법 및 결과분석 등을 현장시험을 통하여 체계적으로 설명하였다.

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