• Title/Summary/Keyword: 동상깊이

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Numerical Analysis of Frost Depth behind the Lining of Road Tunnel in Gangwon Province (수치해석을 통한 강원지역 도로터널 라이닝 배면지반의 동결깊이 분석)

  • Son, Hee-Su;Jun, Kyoung-Jea;Yune, Chan-Young
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.3
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    • pp.15-23
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    • 2017
  • Gangwon Province, located in the northeastern part of South Korea, is the coldest area in South Korea with 90% of the total area as mountainous. Therefore, tunnel damage has been reported continuously in winter. But there has been lack of researches on frost heave occurring behind tunnel lining. In this study, numerical analysis was conducted to investigate the frost depth in road tunnel constructed in Gangwon province. Based on the database on road tunnel and weather in Gangwon province, a standard tunnel shape and geotechnical properties of ground was determined. And then thermal analysis for the frost depth according to the temperature change and ground conditions were conducted. Analysis result showed that the sensitivity to frost heave of metamorphic rock and sedimentary rock is higher than sand. Lower initial ground temperature leads to deeper frost depth and consequently increases frost damage. In addition, lining thickness, specific heat capacity, and thermal conductivity also affect greatly on the variation of frost depth.

A Numerical Analysis on the Characteristics of Frost Heaving at Road Pavement in Korea (국내 도로포장의 동상 특성에 대한 수치해석적 연구)

  • Kweon, Gi-Chul;Oh, Se-Boong;Kim, Hyung-Bae;Choi, Chang-Gyu
    • International Journal of Highway Engineering
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    • v.5 no.2 s.16
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    • pp.37-47
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    • 2003
  • The basic study was performed on the mechanical analysis of frost and heave using program FROST by CRREL, U.S. army corps of engineers. The characteristics of frost heaving in pavement was analyzed by considering climate, pavement sections and subgrade soil conditions in Korea. Water tables were located at the depth of 0.35m, 2m and 3.35m from subgrade. Inputs were evaluated inevitably from the existing references. As a result frost heave and depth were evaluated with respect time. Maximum frost heave decreased lowering the water table and maximum frost depth was less than 15cm from subgrade. Frost action did not affect seriously on the analysis sections.

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A Study of Frost Penetration Depth and Frost Heaving in Railway Concrete Track (콘크리트 궤도의 동결깊이 및 동상량 측정 연구)

  • Lee, Daeyoung;Kim, Youngchin
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.1
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    • pp.35-41
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    • 2014
  • Many infra suructure such as road, railway, building and utility foundations have been damaged by the repeated freezing and thawing of the soil during winter and spring every year in seasonal frost region. The frost penetration depth is most important factor in the design of structure such as road, railway and building in seasonal frost region. This paper presents the results of calculation of frost penetration depth and frost heaving in concrete track for railway construction. Model concrete track were installed near the railway track in Gangwon, Gyeonggi, Choongbuk province and frost penetration depth were measured using methylene blue frost penetration depth gauge. Model concrete track in Cheolwon, frost heaving of concrete track were also evaluated. The measure of maximum frost penetration depth and frost heaving can be applied to design railway track for cold region in Korea.

The Relationship Between Freezing Index and Frost Penetration Depths in Korea National Road (동결지수와 전국 포장국도에서 실측한 동결깊이의 관계)

  • Kim, Youngchin;Hong, Seungseo
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.4
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    • pp.15-24
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    • 2009
  • Korea is known to have seasonal frost during winter and the effect of low temperatures and water may cause a weakening of pavements. For that reason, frost protection layers have been constructed in pavements to avoid damage caused by frost action. The practies established in USA and Japan have been adopted as anti-frost design methods in Korea. However, the characteristics of Korean soils are different. Additionally, there is no formulation of a reasonable equation for frost penetration depth and the criterion to identify potentially frost-susceptible soils in present pavement design manuals in Korea. Therefore, adequate pavement design procedures in seasonal frost areas, as well as construction and maintenance practices are required. In this paper, frost penetration depths along national roads in Korea were measured and analyzed over several years. The frost penetration depth was analyzed with respect to the provinces of Korea and sunny/ shaded areas. Additionally, measurement results were compared to the formula of the US Army Corps of Engineers and Ifukube in Japan.

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Development of Prediction Model of Frost Penetration Depth on Pavement in Korea (포장도로의 실측값을 활용한 한국형 동결깊이 예측모델 개발)

  • Hong, Seung-Seo;Kim, Young-Seok;Kim, Hak-Seung
    • Journal of the Korean Geosynthetics Society
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    • v.9 no.3
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    • pp.47-56
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    • 2010
  • Korea is known to have seasonal frozen ground during a winter season due to climatic and ground conditions. Temperatures below $0^{\circ}C$ cause pavement failure by frost heaving and thaw settlement. A frost protection layer has been constructed in pavements to avoid damage caused by frost action. Anti-frost design methods in Korea have been adopted, which is established in U.S. and Japan. However the characteristics of soils in Korea are different and there are no reasonable modifications to accommodate these characteristics. Therefore, adequate pavement design procedures including seasonal frost action, as well as construction and maintenance practices are required. In this paper, the frost penetration depths along national roads in Korea are presented based on field measurement over several years (1991~2010). The frost penetration depths are analyzed with respect to the Provinces of Korea and sunny/shaded areas.

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The Freezing Characteristics of Pavement Layer Using the Field Road Model Test (현장도로 모형실험을 이용한 포장구성층의 동결 특성 분석)

  • Shin, Eun-Chul;Ryu, Byung-Hyun;Park, Jeong-Jun
    • Journal of the Korean Geotechnical Society
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    • v.26 no.7
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    • pp.71-80
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    • 2010
  • Korea is considered to be a seasonal frozen soil area that thaws in the spring, and freezes in winter. In the current design codes for anti-freezing layer, the thickness of anti-freezing layer is calculated by the depth frozen due to the temperature condition. Therefore, there is a tendency of over-design and applying uniform thickness without the consideration of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential to study the structural appropriateness of pavement layer and bearing capacity besides the seasonal and mechanical properties of pavement materials to take an appropriate and reasonable design of the road structure. In this paper, the evaluation of frost susceptibility on subgrade, ant-freezing layer, subbase was conducted by means of the mechanical characteristics and model experiment. The temperature, heaving amount, unfrozen water contents and freezing depth of soil samples, the subgrade, anti-freezing layer, subbase soils of road construction site were measured to determine the frost susceptibility.

A Study on The Frost Penetration Depth of Pavement with Field Temperature Data (도로포장 현장계측 온도데이터를 이용한 도로포장체의 동결깊이 연구)

  • Shin, Eun-Chul;Lee, Jae-Sik;Cho, Gyu-Tae
    • International Journal of Highway Engineering
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    • v.13 no.1
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    • pp.21-32
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    • 2011
  • The frost penetration depth of pavement is usually estimated from the freezing index that made temperature data analysis of 30 years and decided the thickness of anti-frost layer. The field monitoring region in study was divided into five regions by freezing index 550~650$^{\circ}C{\cdot}$day, 450~550$^{\circ}C{\cdot}$day and 350~450$^{\circ}C{\cdot}$day. Each region has three-section of road pavement such as cutting area, boundary area of cutting and banking, and lower area of banking. The field monitoring system was established both in the section of anti-frost layer and in the section without anti-frost layer. The data analysis was conducted for determination of frost penetration depth within the paved road by the field monitoring system. The result showed that The temperature of subgrade without anti-frost layer shows below zero in centigrade for the region of freezing index 550~650$^{\circ}C{\cdot}$day, up and down around zero degree in subgrade for the region of freezing index 450~550$^{\circ}C{\cdot}$day, and there is no place existed below zero degree in subgrade for the region of freezing index below 450$^{\circ}C{\cdot}$day. With comparison of field frost penetration depth for the cross-sections of pavement, the cutting area shows the greatest frost penetration depth, and less influence of frost penetration depth for the boundary area of cutting and banking, and the least influenced for the lower area of banking.

Structural assessment of Anti-Freezing Layer with use of Falling Weight Deflectormeter Deflection (Falling Weight Deflectormeter를 이용한 동상방지층의 구조적 특성 분석)

  • Lee, Moon-Sup;Kim, Boo-Il;Jeon, Sung-Il;Park, Hee-Mun
    • International Journal of Highway Engineering
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    • v.12 no.2
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    • pp.99-106
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    • 2010
  • Until now, the thickness design of anti-freezing layer has been empirically conducted using the frost depth determined from the freezing index. This approach cannot consider the structural properties of anti-freezing layer, which can cause the over-design of pavement structure. This paper presents results of structural evaluation of anti-freezing layer using the Falling Weight Deflectormeter (FWD) deflections. The FWD testing was directly conducted on top of the subbase layer located at the embankment, cutting, and boundary area of each section. It is observed from this testing that the center deflections of pavement structure with anti-freezing layer are smaller than those without anti-freezing layer. The deflection reduction rates are 15~55% in the embankment, 11~64% in the cutting, and 2~38% in the boundary, respectively. It was also found that the use of antifree zing layer enables to reduce the Surface Curvature Index (SCI) values up to 24 percent. Fatigue lives show that pavement structure with antifreezing layer are about two times higher than the those without anti-freezing layer. This fact indicates that the anti-freezing layer should be considered as a structural layer in the asphalt pavement system.

The Frost Heaving Characteristics of Subgrade Soils Using Laboratory Freezing System (실내동결시스템을 이용한 노상토의 동상 특성)

  • Shin, Eun-Chul;Ryu, Byung-Hyun;Park, Jeong-Jun
    • International Journal of Highway Engineering
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    • v.12 no.2
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    • pp.71-79
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    • 2010
  • The influence of fines of the frost susceptibility of subgrade soils were established by laboratory freezing system test simulating closely the thermal conditions in the field. During the winter season, the climate is heavily influenced by the cold and dry continental high pressure. Because of siberian air mass, the temperature of January is $-6{\sim}-7^{\circ}C$ on average. This chilly weather generate the frost heaving by freezing the moisture of soil and damage potential of the road structure. In the freezing soil, the ice lenses increase the freeze portion of soil by absorbing the ground water with capillary action. However, the capillary characteristics differ from the sort of soil on the state of freezing condition. In the current design codes for anti-freezing layer, the thickness of anti freezing layer is calculated by freezing depth against the temperature condition. Therefore, they have a tendency of over-design and uniform thickness without the considerations of thermal stability, bearing capacity and frost susceptibility of materials. So, it is essential for studying the appropriateness and bearing capacity besides the seasonal and mechanical properties of pavement materials to take a appropriate and reasonable design of the road structure. In this Paper, the evaluation of frost susceptibility was conducted by means of the mechanical property test and laboratory freezing system apparatus. The temperature, heaving amount, heaving pressure and unfrozen water contents of soil samples, the subgrade soils of highway construction site, were measured to determine the frost susceptibility.

The Control of the Ground Frost Heave by Using the Scrap Tire (폐타이어를 이용한 지반동상 방지)

  • 김영진;강병희
    • Geotechnical Engineering
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    • v.14 no.1
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    • pp.49-58
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    • 1998
  • It was investigated whether the scrap tire can be recycled as a construction material for controlling the frost heave of the ground. Some frost heave tests and a frost penetration depth test in the laboratory were performed on the weathered granite soil mitred with variable amount of scrap tire powder under the atmospheric temperature at -$17^{\circ}$ to find the basic effects of the scrap tire on the control of frost. The frost heave control layer of the crushed stone mixed with scrap tire chips directly below thin subbass in the bituminous pavement was found to be effective for practical use. And the equation for the required thickness of this frost heave control layer with freezing index was suggested.

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