• Title/Summary/Keyword: Frost heave

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Freezing and Deflection Characteristics of Flexible Pavement Structure Using Frost Model Test (동상모형실험을 통한 아스팔트 포장체의 동결 및 처짐 특성)

  • Shin, Eun-Chul;Hwang, Soon-Gab;Park, Jeong-Jun
    • Journal of the Korean Geosynthetics Society
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    • v.11 no.3
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    • pp.27-35
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    • 2012
  • In this paper, the frost heaving and thawing characteristics of flexible pavement structure were evaluated in the large scale freezer which have a specification of temperature range $-20^{\circ}C{\sim}10^{\circ}C$ and $3.2m(L){\times}3.2m(B){\times}2.4m(H)$ in size. The insulated steel box with the size of $0.9m(L){\times}0.9m(B){\times}0.9m(H)$ was used to simulate actual pavement road structure. The variation of temperature, frost heave amount and frost heave pressure were measured through the instrument of TDS-602 data logger. LFWD (light falling weight deflectometer) was used to determine the change of deflection due to the frost heaving and thawing. Furthermore, the influence of aggregate layer to the freezing of the subgrade soil was studied to verify the function and effectiveness of the anti-freezing layer.

Development of Numerical Analysis Model for the Calculation of Thermal Conductivity of Thermo-syphon (열 사이펀의 열전도율 산정을 위한 수치해석 모델 개발)

  • Park, Dong-Su;Shin, Mun-Beom;Seo, Young-Kyo
    • Journal of the Korean Geotechnical Society
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    • v.37 no.1
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    • pp.5-15
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    • 2021
  • The areas consisting of frost susceptible soils in cold regions, such as the Arctic area, have problems of frost heave and thaw settlement due to the seasonal air temperature changes and internal temperature of installed structures. Ground stabilization methods for preventing frost heave and thaw settlement of frost susceptible soils include trenching, backfilling and thermo-syphon. The thermo-syphon is the method in which refrigerant can control the ground temperature by transferring the ground temperature to atmosphere in the from of two-phase flow through the heat circulation of the internal refrigerant. This numerical study applied the function of these thermo-syphon as the boundary condition through user-subroutine coding inside ABAQUS and compared and analyzed the temperature results of laboratory experiments.

Effect of XPS and Polyethylene Aggregates in Model Tests for Prevention of Frost Heave in Railroad Track (철도에서의 동상방지를 위한 모형시험에서 XPS 및 PE골재의 설치 효과)

  • Kim, Donggwan;Yoon, Yeowon;Kim, Youngchin
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.10
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    • pp.5-13
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    • 2014
  • In this research, in order to study insulation effect of commercial XPS and recycled PE aggregates for prevention of frost heave in the roadbed of railroad track from the freezing temperature, model tests were carried out in the large freezing room. For this, thermal conductivities were measured for various dry densities, water contents, temperatures and mixing ratios of PE aggregates. From the tests, it can be seen that thermal conductivities of roadbed decrease with the increase of the ratio of mixed PE aggregates. However it was sensitive to the changes of temperature and water content due to the amount of water in the voids. From the model test of railroad track, it can be seen that the time to reach $0^{\circ}C$ was longer for XPS than that for the PE aggregates. Also the test shows best insulation effect can be achieved when XPS board was installed above the PE aggregate layer rather than the opposite order.

A Study on the Method of Analysis and Design of Benchmark Pile in Permafrost Area (영구동토지역에서의 수준말뚝의 안정성 검토 및 설계방법 연구)

  • Jo, Cheon-Hwan;Lee, Won-Je;Hong, Seong-Wan
    • Geotechnical Engineering
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    • v.9 no.2
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    • pp.15-26
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    • 1993
  • Frost heave on foundation(or ice jacking) is defined that foundation is uplifted by heav- ing force exerted around foundation from freezing of soils. This phenominon is often occurred in the light -weight structure e.g, small building, electro - telegraph pole, street light, pipe line, budge and reference point of survey. Frost heave is the most important factor in design of foundation of structure and the key issue in understanding mechanism of foundation in permafrost area. In this study is reviewed the state of the art on the analysis method of frost heave in USSR and is suggested the design method of benchmark pile. On the basis of above results, this study suggests a design chart able to do esign simply the benchmark pile in Yakutsk region.

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Stress and Displacement Analysis of Arctic Frostheave with Gas Pipeline using Finite Element Method (극한지 동상융기에 의한 가스배관과 토양의 응력 및 변위 해석)

  • Kim, Kyung Il;Yeom, Kyu Jung;Oh, Kyu Hwan;Kim, Woo Sik
    • Journal of the Korean Institute of Gas
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    • v.19 no.5
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    • pp.47-53
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    • 2015
  • According to the interest of the arctic's resources rising, many countries are making moves to develop these resources. Korea has also undergone negotiations with Russia to develop natural gas resources in Siberia, which is geographically relatively close. However, the Arctic resources market is dominate, it is essential to develop construction techniques that are suited for the Arctic. Gas pipelines in the Arctic are affected by frost heave due to the region's extremely low temperatures, a condition that is not present in Korea, making it vital to develop a finite element method (FEM) model. This research paper study a model of gas pipe lines in the Arctic and frost heave using FEM.

Analysis of Frozen Reduction Effect and Economic Evaluation of Recycled PET-Soil (재활용 PET 재료를 이용한 골재의 동상저감 효과 분석 및 경제성 평가)

  • Shin, Eun Chul;Shin, Hui Su;Kim, Gi Sung
    • Journal of the Korean Geosynthetics Society
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    • v.13 no.4
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    • pp.153-159
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    • 2014
  • During the winter and spring seasons in Korea, structures such as buried water supply pipelines, roads, railways are frequently damaged due to frost heaving and thawing. Until now, the method of substituting the frost susceptible soil with the gravel or rubbles those are non-frost susceptible materials have been employed in Korea to prevent frost heaving. A series of laboratory soil tests and indoor frozen soil engineering experiments, as well as laboratory frost heaving tests were conducted for seeking the means of utilizing recycled PET bottles as substitute material.

Studies on the Frost Heave Revelation and Deformation Behaviour due to Thawing of Weathered Granite Soils (화강암 풍화토의 동상 발현 및 융해에 따른 변형 거동에 관한 연구)

  • 류능환;최중대;류영선
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.37 no.3_4
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    • pp.61-71
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    • 1995
  • Natural ground is a composite consisted of the three phases of water, air and soil paircies. Among the three components, water as a material is weU understood but soil particles are not in foundation engineering. Especially, weathered granite soil generally shows a large volumetric expansion when they freeze. And, the stability and durability of the soil have shown decreased with repetitive freezing and thawing processes. These unique charcteristics may cause various construction and management problems if the soil is used as a construction material and foundation layers. This project was initiated to investigate the soil's physical and engineering characteristics resulting from freezing and freezing-thawing processes. Research results may be used as a basic data in solving various problems related to the soil's unique characteristics. The following conclusions were obtained: The degree of decomposition of weathered granite soil in Kangwon-do was very different between the West and East sides of the divide of the Dae-Kwan Ryung. Soil particles distributed wide from very coarse to fine particles. Consistency could be predicted with a function of P200 as LL=0.8 P200+20. Permeability ranged from 10-2 to 10-4cm/sec, moisture content from 15 to 20% and maximum dry density from 1.55 to 1.73 g /cmΥ$^3$ By compaction, soil particles easily crushed, D50 of soil particles decreased and specific surface significantly increased. Shear characteristics varied wide depending on the disturbance of soil. Strain characteristics influenced the soil's dynamic behviour. Elastic failure mode was observed if strain was less than 1O-4/s and plastic failure mode was observed if strain was more than 10-2/s. The elastic wave velocity in the soil rapidly increased if dry density became larger than 1.5 g /cm$^3$ and these values were Vp=250, Vg= 150, respectively. Frost heave ratio was the highest around 0 $^{\circ}C$ and the maximum frost heave pressure was observed when deformation ratio was less than 10% which was the stability state of soil freezing. The state had no relation with frost depth. Over freezing process was observed when drainage or suction freezing process was undergone. Drainage freezing process was observed if freezing velocity was high under confined pressure and suction frost process was occurred if the velocity was low under the same confined process.

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Geotechnical Characteristics of Frost-Susceptibility Soil Using Modified Freeze-Thaw Apparatus (변형된 동결-융해 시험장치를 이용한 동상민감성흙의 지반공학적 특성)

  • Shin, Eun-Chul;Ryu, Byung-Hyun;Park, Jeong-Jun
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.1
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    • pp.53-59
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    • 2009
  • A new system of modified freeze-thaw testing apparatus is introduced. This system is developed to evaluate the geotechnical parameters and their dependence upon freezing-thawing history of frost-susceptibility soil. A necessary condition for stationary frost heaving is clarified in this paper. The method changes the thermal boundary condition up to the net heat flow at the freezing frost becomes zero. The effectiveness of this method is verified by freeze-thaw tests. Frost heaving observed after the application of the method is found to be due to another frost heaving action called long-term frost heaving. This frost heaving has already been studied and is considered ignorable as engineering factor because of its small heaving amount.

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