• Title/Summary/Keyword: Differential settlement

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Three-dimensional Modeling Seismic Analysis of Circular Water Reservoirs considering Differential Settlement Effects (부동침하 영향을 고려한 원형 배수지 구조의 3차원 모델링 지진 해석)

  • Lee, Sang-Youl;Choi, Hyung Bae;Ahn, Kwang Sik;Jeong, Gyo-Cheol
    • The Journal of Engineering Geology
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    • v.31 no.1
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    • pp.43-53
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    • 2021
  • Three-dimensional finite element analysis of 1,300 ton stainless water reservoirs was undertaken to consider differential settlement effects of the reservoir when subjected to earthquake loads. The earthquake load for large (>1,000 ton) water reservoirs are further determined using a specification established from the Korean Standards Association. The structural behavior of water reservoirs with differential settlements can be heavily dependent on seismic loading effects. Stress and displacement distributions are induced for various load combinations, including for with and without differential settlements. From numerical examples, the induced maximum displacements of the water reservoirs largely increase with differential settlements compared to those without differential settlements.

Long-term Settlement of High Speed Railway Embankment Compacted under Dry/Wet Condition (고속철도 토공구간 쌓기 재료의 다짐함수비 조건에 따른 장기침하 특성)

  • Lee, Sung-Jin;Lee, Il-Wha;Lee, Jin-Uk
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1268-1277
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    • 2008
  • Recently, the high speed railway comes into the spotlight as the important and convenient traffic infrastructure. In Korea, Kyung-Bu high speed train service began in about 400km section at 2004, and the Ho-Nam high speed railway will be constructed by 2017. The high speed train will run with a design maximum speed of 300-350km/hr. Since the trains are operated at high speed, the differential settlement of subgrade under the rail is able to cause a fatal disaster. Therefore, the differential settlement of the embankment must be controlled with the greatest care. Furthermore, the characteristics and causes of settlements which occurred under construction and post-construction should be investigated. A considerable number of studies have been conducted on the settlement of the natural ground over the past several decades. But little attention has been given to the compression settlement of the embankment. The long-term settlement of compacted fills embankments is greatly influenced by the post-construction wetting. This is called 'hydro collapse' or 'wetting collapse'. This wetting collapse problem for the compressibility of compacted sands, gravels and rockfills, has been recognized by several researchers. For this wetting settlement problem, we showed the test results carried out with 4 fill materials. These tests were performed under the condition that the fill materials were inundated at the first wetting. Subsequently, in this study, we investigated the long-term settlement characteristics of the fill materials under the repeated partial wetting and rising of the ground water table happend by rainfall.

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Analysis of Residual Settlement of Concrete Track Roadbed for High-Speed Railway (고속철도 콘크리트궤도 토공노반의 잔류침하 분석)

  • Lee, Il-Wha;Lee, Sung-Jin;Kwon, Oh-Jung;Jeong, Uhn-Ghi
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.369-374
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    • 2007
  • An active application of concrete track is being expected for the future construction of Korean railroad. For the successful concrete track construction and design in earthwork areas, the residual settlement should be reasonably estimated using the proper method. The concrete track is extremely vulnerable to the damage of residual settlement. However, at the transition areas such as bridge approach, differential settlement will likely occur due to difference of stiffness, poor drainage and poor ground treatment. The maintenance is very difficult for excessive settlement on existing line, it is need to constrain the residual settlement in step of design. In this paper, it is performed the analysis of the residual settlement measured data, test results and reference to understand the residual settlement behavior of concrete track roadbed

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Study of Determination of Allowable Residual Settlement of Concrete Track Roadbed for High-Speed Railway (콘크리트궤도 토공노반의 허용잔류침하량 결정에 관한 연구)

  • Lee, Il-Wha;Yang, Shin-Chu;Jang, Seung-Yup
    • Proceedings of the KSR Conference
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    • 2007.11a
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    • pp.1121-1125
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    • 2007
  • An active application of concrete track is being expected for the future construction of Korean railroad. For the successful concrete track construction and design in earthwork areas, the residual settlement should be reasonably estimated using the proper method. The concrete track is extremely vulnerable to the damage of residual settlement. However, at the transition areas such as bridge approach, differential settlement will likely occur due to difference of stiffness, poor drainage and poor ground treatment. The maintenance is very difficult for excessive settlement on existing line, it is need to constrain the residual settlement in step of design. In this paper, it is performed the determination of the allowable residual settlement through various study to understand the residual settlement behavior of concrete track roadbed.

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Analysis of settlements of space frame-shear wall-soil system under seismic forces

  • Jain, D.K.;Hora, M.S.
    • Earthquakes and Structures
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    • v.8 no.5
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    • pp.1255-1276
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    • 2015
  • The importance of considering soil-structure interaction effect in the analysis and design of RC frame buildings is increasingly recognized but still not penetrated to the grass root level owing to various complexities involved. It is well established fact that the soil-structure interaction effect considerably influence the design of multi-storey buildings subjected to lateral seismic loads. The shear walls are often provided in such buildings to increase the lateral stability to resist seismic lateral loads. In the present work, the linear soil-structure analysis of a G+5 storey RC shear wall building frame resting on isolated column footings and supported by deformable soil is presented. The finite element modelling and analysis is carried out using ANSYS software under normal loads as well as under seismic loads. Various load combinations are considered as per IS-1893 (Part-1):2002. The interaction analysis is carried out with and without shear wall to investigate the effect of inclusion of shear wall on the total and differential settlements in the footings due to deformations in the soil mass. The frame and soil mass both are considered to behave in linear elastic manner. It is observed that the soil-structure interaction effect causes significant total and differential settlements in the footings. Maximum total settlement in footings occurs under vertical loads and inner footings settle more than outer footings creating a saucer shaped settlement profile of the footings. Each combination of seismic loads causes maximum differential settlement in one or more footings. Presence of shear wall decreases pulling/pushing effect of seismic forces on footings resulting in more stability to the structures.

Behavior of Rapidly Expansion Materials for Maintenance Railroad Bed Subjected to Cyclic Loading (반복하중을 받는 철도노반 보수용 급속 팽창재료의 거동)

  • Lee, Jundae;Shin, Eunchul
    • Journal of the Korean GEO-environmental Society
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    • v.10 no.2
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    • pp.45-50
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    • 2009
  • The differential settlement may be generated by the variation of stresses caused by the soft ground or ground water. The cracks are usually created when the structures are leaned or deformed due to the differential settlement. A grouting method has been mainly used till now to improve the bearing capacity of the ground when the foundation of the structure is deformed by differential settlements. However, when this method is used, it takes too long time to obtain the required strength and the period of the reinforcement effect is not long enough. The advantage of GPCON injection method is to have good mechanical properties and durability, and easy construction. In addition, the GPCON method rapidly fills up the void in soils by injecting some materials into underground and also obtain the increase of bearing and shearing forces due to the expansion. In this paper the restoration capability of the foundation settlement of railway and subway subjected to cyclic loading is analytically and experimentally evaluated using the high density rapidly expansion GPCON in order to investigate the types of deformations and vibrational characteristics.

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Numerical Model Study on a Scheme to Restrain Deformation of a Conduit with Flexible Joint(I) : Effectiveness of Soil Reinforcement (연성이음관의 변형억제방안에 관한 수치모델연구(I): 기호지반 보강효과)

  • 손준익;정하익
    • Geotechnical Engineering
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    • v.7 no.4
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    • pp.5-14
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    • 1991
  • This paper reports the application study of the ground reinforcement under a buried conduit subjected to differential settlement via a finite element modeling. The soil-reinforcement inter- action helps to minimize the differential settlement between the adjoining conduit segments. Three different field conditions have been considered. The settlement pattern and deformation slope have been evaluated for each boundary condition. The analysis results are compared for both non-reinforced and reinforced case to measure the effectiveness of the soil reinforcement for restraining deformation of the conduit.

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Numerical Model Study on a Scheme to Restrain Deformation of a Conduit with Flexible Joints(II) : Effectiveness of Concrete Bedding Reinforcement (연성이음관의 변형억제방안에 관한 수치모델연구(II): 콘크리트베딩 보강효과)

  • 손준익;정하익
    • Geotechnical Engineering
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    • v.7 no.4
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    • pp.15-24
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    • 1991
  • This paper reports the application study of the concrete bedding reinforcement under a buried conduit with flexible joints subjected to differential settlement via a finite elemen modeling. The reinforcement of concrete bedding helps to minimize the differential settlement between the adjoining conduit segments. Three different field conditions have been considered. The settlement pattern and deformation slope have been evaluated for each boundary condition. The analysis results are compared for both non-reinforced and reinforced cases to measure the effectiveness of concrete bedding reinforcement for restraining deformation of a conduit with flexible joints.

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Investigation of Bracket Deflection Influence on Structural Safety of Scaffold System (브라켓의 변위가 비계 구조 안전성에 미치는 영향 분석)

  • Kim, Dong Hyun;Lee, Hyung Do;Won, Jeong-Hun;Jung, Sung Hoon
    • Journal of the Korean Society of Safety
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    • v.32 no.3
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    • pp.66-73
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    • 2017
  • This study examined the structural behavior of bracket scaffolds reflecting the influence of bracket's deflection. Even though the supporting condition of bracket scaffolds is different to that of general earth-supported scaffolds, there is no clear standards about the installation of bracket scaffolds. To compare the structural behaviors of the earth-supported scaffolds without settlements in columns and those of bracket scaffolds installed on the bracket structure, the finite element analysis was performed. The results show that the differential settlement between the scaffold columns installed on the bracket was occurred due to the deflection of the bracket. The differential settlement gave birth to remarkable secondary stress to the scaffold columns. It is resonable to locate all scaffold columns on the brackets, and if unavoidable situation is faced at a site, the horizontal members should not placed alone without columns on the brackets. Moreover, the structural analysis should be performed to ensure structural safety of bracket scaffolds before installation. In addition, the location of wall connection to the structures is recommended to the scaffolds columns installed on the brackets.

Effectiveness of Reinforcement by Geogrid & Pile in Soft Clay (지오그리드와 말뚝에 의한 연약지반 보강효과)

  • 신은철;이상혁;이명원
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.09a
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    • pp.61-69
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    • 2000
  • It is not easy to find a good soil condition due to the shortage of suitable land for construction work. The earth structure and buildings can be constructed over the soft soil. The soft soil must be treated either using the reinforcement element or dewatering. Most of land reclamation projects are being implemented along the south coast or west coast of the Korean Peninsula. The soils in these areas are covered with the soft marine clay, so soil and site improvement is the most important things to do. Pile foundation at the bottom of embankment can be constructed either in the soft ground or in the soil contaminated area. The purpose of this research is to develop "geogrid-reinforced piled embankment method" to prevent the differential settlement and increase the bearing capacity of soil. In this study, the effectiveness of the geogrid-reinforcement was studied by varying the space between piles and reinforcement conditions. Also, the geotechnical engineering properties of the embankment material and foundation soil were determined through the laboratory tests as well as the field tests. As a result, the site that the pile-spacing S = 3b with geogrid reinforcement is the most effective to reduce the differential settlement and increase load bearing capacity.

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