• Title/Summary/Keyword: retaining wall

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Merits and Demerits of the Inspection System introduced in Construction of City Planning Road: In Case of Crossing Road of the Aioiyama Green Area in Nagoya

  • Yutaka Okamura
    • Journal of the Korean Institute of Landscape Architecture International Edition
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    • no.2
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    • pp.178-184
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    • 2004
  • The Yatomi - Aioiyama line is a city-planning road that was notified in 1957 and subsequently prepared by land readjustments. Currently, approximately 900m of road pass in the inside of the Aioiyama green area has not been constructed. The surveying briefing session for inhabitants was held in July 1992, the project was authorized by the Ministry of Land, Infrastructure and Transport in September 1993, and the project briefing session for inhabitants was held in September 1993. The site purchase has been completed. At the May 2000 briefing session, inhabitants of the area began voicing dissenting demanding the conservation of the natural environment of this green area. The inspector system serves as the third party, independent of both the administration and the inhabitants. Before finalizing the geometric line form of the road to be constructed, some surveys of animals and plants found along the walking trails carried out intensively in the northern area, which is approximately 50 ha, of the Aioiyama green area. The natural environment inspector submitted a plan for changing the geometric line form of the road decided upon by city planning, and it was approved by the city planning council. If the shelter structure or the retaining wall structure is adopted at the location where large slope faces are produced by excavation or landfill, and if the bridge structure is adopted at the place where stream-lines and walking trails intersect, it leads to a reduction of approximately $40\%$ in the areas for which change is planned. Furthermore, approximately $20\%$ of the area to be changed is restored by returning soil to the roof of the shelter.

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A Study on the Structure Types and Concrete Strength Zoning of Domestic Tall Apartment Buildings (국내 초고층 주상복합 건축물의 구조시스템 유형과 콘크리트 강도 조닝 분석)

  • Kim, Sang-Yeon
    • Land and Housing Review
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    • v.4 no.3
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    • pp.295-301
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    • 2013
  • In this study, cases of domestic tall residential buildings were investigated for the structural types, numbers of stories, total heights, type of lateral load resisting systems, and zoning of concrete strength. Based on these investigation data, the structural planning pattern of tall residential building was analyzed. SRC structure is main structural types of tall residential building at the initial stage of domestic tall residential building, but RC structure is substituted for main structural types since 2005. Retaining wall system is positioned at the core part of structural plan as a lateral load resisting system. Concrete strength zoning of vertical members like columns are divided by vertical heights of lower parts, middle parts, and upper parts. Basic data of structural planning of 40stories and 60 stories residential buildings was proposed based on case investigation.

Slope Stability Analysis Considering Reinforcing Effects of Geosynthetics (토목섬유의 보강효과를 고려한 사면안정해석)

  • Kim, Kyeong-Mo;Kim, Hong-Tack;Lee, Hyung-Kyu
    • Journal of the Korean GEO-environmental Society
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    • v.6 no.1
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    • pp.73-82
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    • 2005
  • Generally, to evaluate a slope stability of the geosynthetic reinforced soil slope, the modified version of limit equilibrium method can be used. In most cases, resisting effects of reinforcement are dealt with considering an increased shear strength on the potential slip surface. However, it is not clear that the methods satisfy all three equilibrium equations. In this study, the new slope stability analysis method in which not only reinforcing effects of geosynthetics can be considered but also all three equilibrium equation can be satisfied is proposed. A number of illustrative examples, including published load test of large-scale reinforced retaining wall and centrifuge model tests on the geotextile reinforced soil slopes, are also analyzed. As a result, it is shown that the newly suggested method produces a relatively accurate factor of safety.

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Numerical Study on the Behavior of Ground and Structure in Geosynthetic-Reinforced Soil (GRS) Integral Bridges

  • Sim, Youngjong;Jin, Kyu-Nam;Hong, Eun-Soo;Kim, Hansung;Park, Jun Kyung
    • Land and Housing Review
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    • v.12 no.3
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    • pp.97-108
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    • 2021
  • In bridge abutment structures, lateral squeeze due to lateral stress of embankment placement and thermal movement of the bridge structure leads to failure of approach slabs, girders, and bridge bearings. Recently, GRS (Geosynthetic-Reinforced Soil) integral bridge has been proposed as a new countermeasure. The GRS integral bridge is a combining structure of a GRS retaining wall and an integral abutment bridge. In this study, numerical analyses which considered construction sequences and earthquake loading conditions are performed to compare the behaviors of conventional PSC (Pre-Stressed Concrete) girder bridge, traditional GRS integral bridge structure and GRS integral bridge with bracket structures (newly developed LH-type GRS integral bridge). The analysis results show that the GRS integral bridge with bracket structures is most stable compared with the others in an aspect of stress concentration and deformation on foundation ground including differential settlements between abutment and backfill. Furthermore, the GRS integral bridge with/without bracket structures was found to show the best performance in terms of seismic stability.

A Study on the Possibility of Using Concrete Blocks with Ready Mixed Concrete Sludge (레미콘 슬러지를 활용한 콘크리트블록 활용에 대한 기초 연구)

  • Jung, Jae-Ho
    • Journal of the Korea Institute of Building Construction
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    • v.19 no.4
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    • pp.307-312
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    • 2019
  • Sludge generated in the production of ready-mixed concrete is classified as waste and processed at a high cost. In particular, small and medium-sized ready-mix manufacturer are burdened with such costs, and some companies are illegally processing them. Therefore, the purpose of this study is to suggest a method for recycled remicon sludge as a concrete block composition. When the remicon sludge is simply dried, the residual chemical admixture and ettringitee contained in the sludge are present, so that the compressive strength of the concrete block and the compressive strength after freezing and thawing are largely deteriorated to meet the quality standards of the concrete shore and retaining wall block It was not possible to do. As a method for satisfying the physical performance, it was found that the remicon sludge was calcined at a high temperature of about $900^{\circ}C$. to decompose ettringite and residual chemical admixture and then used it.

The Process of Place-making and the Placeness of the 'Kim Gwang-seok Road' in Daegu ('김광석 다시 그리기 길'의 장소 만들기와 장소성)

  • Park, Soon Ho
    • Journal of the Economic Geographical Society of Korea
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    • v.23 no.4
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    • pp.438-453
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    • 2020
  • This study attempts to examine the process of place-making, to define the role and interrelationship of the subjects and to analyze the placeness of the 'Kim Gwang-seok Road', a representative example of artificial place-making. Through a 10-year urban regeneration project based on the concept of Kim Gwang-seok, the alleyway between Bangcheon Market and the retaining wall of Sincheon-daero has been embedded as a memorial space for Kim Gwang-seok and an cultural art space. However, the existing placeness has weakened as the result of the excessive tourism in the late 2010s, while the characteristics of cultural commercial space has strengthened. This change in place has prompted community disintegration, which has caused the loss of momentum for sustainable development. To overcome these problems, it will be necessary to establish endogenous governance to expand and reproduce existing community capabilities, embedded social capital and place assets in new directions.

The July 2, 2017, Lantian landslide in Leibo, China: mechanisms and mitigation measures

  • He, Kun;Ma, Guotao;Hu, Xiewen;Liu, Bo;Han, Mei
    • Geomechanics and Engineering
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    • v.28 no.3
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    • pp.283-298
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    • 2022
  • Landslides triggered by the combination of heavy precipitation and anthropological disturbance in hilly areas cause severe damage to human lives, properties, and infrastructure constructions. A comprehensive investigation of the influencing factors and failure mechanisms of landslides are significant for disaster mitigation and prevention. This paper utilized the combination of detailed geological investigation, physical experimental testing as well as numerical modelling to determine the failure mechanism, and proposed a countermeasures of the Lantian landslide occurred on 2, July 2017. The results reveal that the Lantian landslide is a catastrophic reactivated slide which occurred in an active tectonic region in Southwest China. Because of the unique geological settings, the fully to highly weathered basalts in the study area with well-developed fractures favored the rainwater infiltration, which is the beneficial to slide reactivation. Engineering excavation and heavy precipitation are the main triggering factors to activate the slide motion. Two failure stages have been identified in the landslide. The first phase involves a shallow mass collapse originated at the upper slopes, which extends from the road to platform at rear part, which is triggered by excavation in the landslide region. Subjected to the following prolonged rainfall from 19 June to 2 July, 2017, the pore water pressure of the slope continually increased, and the groundwater table successively rise, resulting in a significant decrease of soil strength which leads to successive large-scale deep slide. Thereinto, the shallow collapse played a significant role in the formation of the deep slide. Based on the formation mechanisms of the landslide, detailed engineering mitigation measures, involving slope cutting, anchor cable frame, shotcrete and anchorage, retaining wall and intercepting ditch were suggested to reduce the future failure risk of the landslide.

Slope Stability in Logging Areas Using Unmanned Aerial Vehicle Imaging (무인항공기 영상 촬영을 활용한 벌목지역의 비탈면 안정성 평가)

  • Kim, Tae-Wan;Yoo, Hyung-Sik;Park, Seok-In;Kim, Jae-Hong
    • Journal of the Korean Geotechnical Society
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    • v.38 no.7
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    • pp.39-47
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    • 2022
  • This study aims at evaluating the stability of disaster risks, such as schools, apartments, and geotechnical structures located around slopes in urban areas. The research conducted an aerial photography analysis on where the slope of the retaining wall behind 𐩒𐩒 High School in Gwangju collapsed in August 2018 due to heavy rain. In general, the overflow of rainwater has been managed through drainage channels around slopes during the rainy season, and the surface flow of rainfall was limited due to the presence of dense forests in the area. However, when the slope collapsed, a lot of water flowed out of the ground, and the saturated surface layer ground was destroyed. To analyze the cause, the changed terrain of the upper slope area, which could not be directly identified, was photographed using unmanned aerial vehicles. Digital Elevation Model by unmanned aerial vehicle shooting was performed by analyzing the slope map, calculating the direction of rainfall and the length and width of water-logged areas. The change in the instability of the slope over time due to a 10-day rainfall was also analyzed through numerical analysis.

Time-dependent Deformation Charateristics of Geogrid Using Wide Width Tensile Test (광폭인장시험을 통한 지오그리드의 시간의존적 변형 거동 고찰)

  • Yoo, Chung-Sik;Jeon, Han-Yong;Kim, Sun-Bin
    • Journal of the Korean Geotechnical Society
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    • v.24 no.1
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    • pp.71-80
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    • 2008
  • This paper presents the reusults of wide width tensile tests under sustained and cyclic loads with vairous loading rate on geogrids. A seires of modified wide width tensile tests were conducted to investigate the effect of tensile strain rate on the deformation behavior of the geogrids. In addition, residual deformation characteristics of a geogrid under sustained or cyclic tests were also investigated. The results indicated that the residual deformation of a geogrid is strongly related to the viscous behavior of the geogrid, and the residual deformation can be well described by a hyperbolic curve. Also revealed was that residual deformation of a geogrid when subject to sustained or cyclic load should be described with the framework of viscous behavior.

Time-dependent Deformation Characteristics of Geosynthetic Reinforced Modular Block Walls under Sustained/cyclic Loading (지속하중 및 반복하중 재하시 보강토 옹벽의 잔류변형 특성)

  • Yoo, Chung-Sik;Kim, Young-Hoon;Han, Dae-Hui;Kim, Sun-Bin
    • Journal of the Korean Geotechnical Society
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    • v.23 no.6
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    • pp.5-21
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    • 2007
  • Despite a number of advantages of reinforced earth walls over conventional concrete retaining walls, there exit concerns over long-term residual deformation when they are subjected to repeated and/or cyclic loads, especially when used as part of permanent structures. In view of these concerns, in this paper time-dependant deformation characteristics of geosynthetic reinforced modular block walls under sustained anuor repeated loads were investigated using reduced-scale model tests. The results indicated that a sustained or repeated load can yield appreciable magnitude of residual deformation, and that the residual deformations are influenced not only by the loading characteristics but by the mechanical properties of geogrid. It is also found that the preloading technique can be effectively used in controlling residual deformations of reinforced soils subjected to sustained and/or repeated loads.