• Title/Summary/Keyword: Road embankment

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Creep Deformation Characteristics of Weathered Granite Soil (화강풍화토의 creep 변형특성)

  • Park, Heung-Gyu;Kim, Yong-Ha;Paeng, Woo-Seon;Lee, Hae-Soo
    • Journal of the Korean Geotechnical Society
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    • v.23 no.12
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    • pp.43-52
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    • 2007
  • This study analyzes the characteristics of creep deformation behavior of weathered granite soils used in road embankments. The creep strain under the unconfined compressive state demonstrated an excellent agreement with the theoretical analysis of the burgers substance. The elastic deformation showed a termination in its characteristics after a long-term period owing to the increase in applied loads. The primary creep strain was 0.0028 and concluded that the deformation completed within $3{\sim}5$ days after applying the loads. Also, the completing time of creep deformation in the embankment soils increased in proportion to the height of embankment soils. The secondary creep strain is about 50% of the primary creep strain.

Environmental Impact Assessment and Environmental Management of Railways (I) (철도사업 환경영향평가와 환경관리(I))

  • Lee, Hyun-Woo;Lee, Young-Joon;Park, Young Min;Lee, Jeongho;Yoon, Mikyung
    • Journal of Environmental Impact Assessment
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    • v.13 no.6
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    • pp.295-305
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    • 2004
  • After the Rio declaration on environment and development in 1992, developed countries are undertaking "environmentally sustainable transportation (EST)" projects. To meet the needs for EST, current transportation policies in Korea are rapidly reforming and one of its concerns is modernizing and upgrading railway freight system. Planning new railroad construction projects is increasing and subsequent environmental impact assessment (EIA) demands improvements, especially in both the EIA and decision making systems. In this paper, we discuss the present status of EIA for railroad construction projects, especially, by analyzing the EIA documents for the last six years. The EIA for railroad construction projects accounts for only 4.9% of total 918 project EIAs during 1998-2003, and the portion is gradually increasing. Major environmental concerns for EIA in railroad construction projects were geomorphological and ecological changes, protection of rare organisms, air pollution, water pollution, waste management, and noise, etc. We compared characteristics of environmental impacts of railroad construction with those of vehicle road construction, based on environmental and construction-planning indicators appeared in Environmental Impact Statements. Railroad construction usually requires longer tunnels and bridges for a given length than those for vehicle road construction. In addition, the amounts of geomorphological and ecological changes (road-cutting, embankment, devegetation, etc.) in railroad construction were generally less than 50% of those in vehicle road construction. To develop environmentally friendly railway systems, monitoring studies for environmental impacts of railroads such as habitat fragmentation and road kills, dispersal of alien plants, tunnelling effects on groundwater and vegetation, and noise impacts are highly recommended.

Ultimate Capacity of Guardrail Supporting Pile Subjected to Lateral Impact Load Using Centrifuge Model Test (원심모형실험을 통한 차량방호울타리 지지말뚝의 수평방향 충격하중에 대한 극한지지력)

  • Yun, Jong Seok;Lee, Min Jy;Choo, Yun Wook
    • Journal of the Korean Geotechnical Society
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    • v.35 no.11
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    • pp.25-36
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    • 2019
  • The safety barrier is installed on road embankment to prevent vehicles from falling into road side slope. Among the safety barrier, flexible guardrails are usually installed. The flexible guardrail generally consists of a protection cross-beam and supporting in-line piles. These guardrail piles are installed nearby slope edge of road embankment because the side area of the road is much narrow. The protection cross-beam absorbs impact energy caused by vehicle collision. The pile-soil interaction also absorbs the rest of the impact energy and then, finally, the flexible guardrail system resists the impact load. This paper aims to investigate the pile-soil interaction subjected to impact load using centrifuge model tests. In this study, a single pile was installed in compacted residual soil and loaded under lateral impact load. An impact loading system was designed and developed available on centrifuge tests. Using this loading system, a parametric study was performed and the parameters include types of loading and ground. Finally, the ultimate bearing capacity of supporting pile under impact load was analyzed using load-displacement curve and soil reaction pressure distributions at ultimate were evaluated and compared with previous studies.

Present Status and Future Vision of EIA for Railroad Construction Projects (철도건설사업 환경영향평가의 현황과 과제)

  • Lee Hyun-Woo;Lee Young-Joon;Park Young Min;Yoon Mikyung
    • Proceedings of the KSR Conference
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    • 2004.06a
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    • pp.296-302
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    • 2004
  • After the Rio declaration on environment and development in 1992, developed countries are undertaking 'environmentally sustainable transportation (EST)' projects. To meet the needs for EST, current transportation policies in Korea are rapidly reforming and one of its concerns is modernizing and upgrading railway freight system. Planning new railroad construction projects is increasing and subsequent environmental impact assessment (EIA) demands improvements, especially in both the EIA and decision making systems. In this paper, we discuss the present status of EIA for railroad construction projects, especially, by analyzing the EIA documents accumulated for last six years. The EIA for railroad construction projects .accounts for only $4.9\%$ of total project EIAs during 1998-2003. However, the portion is gradually increasing. Major environmental concerns for EIA in railroad construction projects were geomorphological and ecological changes, protection of rare organisms, air pollution, water quality, wast management, noise, etc. We also compared the characteristics of environmental impacts of railroad construction with those of vehicle road construction. The result shows that railroad construction usually requires 3${\~}$4 times longer tunnels and bridges for a given length than vehicle road construction. In addition, the amounts of geomorphological and ecological changes (road-cutting, embankment, devegetation, etc.) in railroad construction were generally less than $40\%$ of those in vehicle road construction. In order to develop environmentally friendly railway systems, monitoring studies for environmental impacts of railroads such as habitat fragmentation and road kills, dispersal of alien plants, tunnelling effects on groundwater and vegetation, and noise impacts are highly required.

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Prediction of Lateral Flow due to Embankments for Road Construction on Soft Grounds with Vertical Drains (연직배수재가 설치된 연약지반 상에 도로성토로 인한 측방유동 발생 예측)

  • Hong, Won-Pyo;Kim, Jung-Hoon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.32 no.6C
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    • pp.239-247
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    • 2012
  • Some methods were proposed to predict lateral flow due to embankments for road constructions on soft grounds, in which vertical drains were placed. In order to investigate the prediction methods of lateral flow, 200 field monitoring data for embankments in thirteen road construction sites at western and southern coastal areas of the Korean Peninsula were analyzed. For analyzing the relationship between the safety factor of embankment slope and the horizontal displacement in soft grounds where horizontal drain mats were placed, it was reliable to apply the maximum horizontal displacement in soft ground instead of the horizontal displacement at ground surface. The maximum horizontal displacement was developed less than 50mm in fields where the safety factor of slope was more than 1.4, while the one was developed more than 100mm in fields where the safety factor of slope was less than 1.2. In safe fields where the maximum horizontal displacement were developed within 50mm, lateral flow would not happen since shear deformation was not appeared. On the other hand, shear failure would happen in the fields where the maximum horizontal displacement were developed more than 100mm. In such fields, embankments might be continued after some appropriate countermeasures should be prepared. Safe embankments can be performed on soft grounds, in which the stability number is less than 3.0 and the safety factor for bearing is more than 1.7. However, if the stability number is more than 4.3 and the safety factor for bearing is less than 1.2, shear deformation would begin and even shear failure would happen.

Impact on Introduction of the Alien Plants by Road Development Projects (도로개발 사업이 외래식물 유입에 미치는 영향)

  • Chu, Yunsoo;Kim, Jung-Kwon;Lee, Hyohyemi
    • Ecology and Resilient Infrastructure
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    • v.4 no.3
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    • pp.156-168
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    • 2017
  • Linear development such as road and railway construction is considered to be an important factor in the dipersion agent of alien species. The purpose of this study is to investigate the effect of road project implementation on the introduction of alien plants. We selected the roadworks that have been completed or completed by more than 70% of the projects in the Han River basin environment agency. The alien plant data were divided into five phases: pre-construction (P0) and construction (P25, P50, P75, P100) according to the annual process rate. As the construction progresses, the naturalization rate, the urbanization index and the tendency of the number of exotic plants increase. Especially, alien plants were introduced rapidly at the beginning of the construction period, and the introduced species continued to appear until the construction was completed. Therefore, it is necessary to minimize the introduction of ailen plants by concentrating management of embankment process and the vegetation restoration process at the beginning of roadworks.

Time effect of pile-soil-geogrid-cushion interaction of rigid pile composite foundations under high-speed railway embankments

  • Wang, Changdan;Zhou, Shunhua;Wang, Binglong;Guo, Peijun
    • Geomechanics and Engineering
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    • v.16 no.6
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    • pp.589-597
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    • 2018
  • Centrifuge model tests were used to simulate pile-raft composite foundation and pile-geogrid composite foundation with different pile spacing for researching the time effect of negative skin friction of rigid piles in high-speed railways. The research results show that the negative skin friction has a significant impact on the bearing capacity of composite foundation. Pile-raft composite foundation has higher bearing capacity compared to pile-geogrid composite foundation to reduce the effect of negative skin friction on piles. Both the foundation settlement and negative skin friction have significant time effect. The distribution of skin friction can be simplified as a triangle along the pile. The neutral point position moves deeper in the postconstruction stage at larger pile spacing. For pile-geogrid composite foundation, the setting of pile-cap affects the position of neutral point in the post-construction stage. Reinforced cushion with geotextile may promote the better performance of cushion for transmitting the loads to piles and surrounding soils. Arching effect in the cushion of the composite foundation is a progressive process. The compression of the rigid piles contributes less than 20% to 25% of the total settlement while the penetration of the piles and the compression of the bearing stratum below the pile tips contribute more than 70% of the total settlement. Some effective measures to reduce the settlement of soils need to be taken into consideration to improve the bearing capacity of pile foundation.

Application Case of Test of Revegetation Measures on Design of Slopes Revegetation and Tentative Instruction on Construction Work -With a Case of Slopes Along the National Road Between Nongseo and Eomo - (비탈면 녹화 설계 및 시공 잠정 지침 적용사례 -농소어모구간 국도비탈면을 중심으로-)

  • Jeon, Gi-Seong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.4
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    • pp.95-108
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    • 2007
  • Test application of revegetation measure was made on the roadside slope damaged by Nongseo-Eomo national road improvement project in a bid to prevent the soil from being washed out as well as to restore the ecological environment, and the survey for assessment of the effect of slope revegetation measures was conducted, beginning May 11 through Nov 7, 2006. In the wake of comprehensive reviewing and evaluating the surrounding topographic environment, physical and chemical characteristics of soil, germination of revegetation plants, analysis of bio mass, covering ratio and the plants appeared, measure b was found to have been most appropriate to cut blasting rock slope, and alternatively measure c. For cut ripping rock slope, measure c-1 appeared to be effective in revegetation effect, and alternatively, b-1.When it comes to cut soil slope, measure c-2 was found to be effective, and b-2 to be a good alternative. And for embankment soil slope, measure b-3 appeared to be most efficient in revegetation effect and measure f as alternative.

Application Case of Test of Revegetation Measures on Design of Slopes Revegetation and Tentative Instruction on Construction Work -With a Case of Slopes Along the National Road Between Gimcheon and Eomo - (비탈면 녹화 설계 및 시공 잠정 지침 적용사례 -김천어모구간 국도비탈면을 중심으로-)

  • Jeon, Gi-Seong
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.10 no.4
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    • pp.83-94
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    • 2007
  • Test application of revegetation measure was made on the roadside slope damaged by Gimcheon-Eomo national road improvement project in a bid to prevent the soil from being washed out as well as to restore the ecological environment, and the survey for assessing the effect of slope revegetation measures was conducted, beginning Sep 7 through Sep 20, 2006. In the wake of comprehensive reviewing and evaluating the surrounding topographic environment, physical and chemical characteristics of soil, germination of revegetation plants, analysis of bio mass, covering ratio and the plants appeared, revegetation measure C was found to have been most effective and desirable for further application in the area. Viewing the specific applicability by the area, revegetation measure C and C-1 appeared to be appropriate for blasting rock slope and ripping rock slope as they are efficient in preventing the slope from being washed out and in early revegetating. And revegetation measure B deemed to be effective to blasting rock slope or ripping rock slope as an alternative. And for cut slope, vegetation measure C-2 was judged to be more effective than measure D or E, while measure C-3 would be appropriateto embankment slope.

A Study on the Freezing and Thawing Resistance of Permeable Polymer Concrete (투수성 폴리머 콘크리트의 동결융해 저항성에 관한 연구)

  • 박응모;조영국;소양섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.331-336
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    • 1999
  • Permeable polymer concrete in this study is one of the environment conscious concrete that can be applied at road, side walks and river embankment, etc. The purpose of this study is to evaluate the effects of mix proportions such as resing content, filler-binder ratio and aggregate ratio on the freezing and thawing resistance of permeable polymer concrete. The permeable polymer concrete are prepared with the resin ratio of 5%, 6% and 7%, filler-binder ratio of 0, 0.5 and 1.0, and 2.5~5mm sized aggregate ratio to standard sand of 10:10, 10:20, 20:10 and 20:20. It is tested for freezing and thawing test according to ASTM C 666092, and then, weight change, length change, relative dynamic modulus, durability factor, and compressive and flexural strengths after test are measured. From the test results, the resistance to freezing and thawing of permeable polymer concrete increased with increase the resing content, filler-binder ratio and fine aggregate ratio.

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