• Title/Summary/Keyword: Embankment on Soft Soil

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Prediction of Settlement for the Highly Plastic and Silty Soft Ground Contained of the Organic Deposits (유기질층을 포함한 고소성 실트질 연약지반의 침하 예측)

  • Yoo, Nam-Jae;Kim, Kyum;Yoo, Chang-Sun
    • Journal of Industrial Technology
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    • v.31 no.B
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    • pp.91-98
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    • 2011
  • In this thesis, from the results of settlement measurement performed at the site where embankment earthwork was carried out on the ground consisting of highly plastic and silty soft soils interlayered with organic deposits, various methods of predicting the embankment settlement such as Hoshino's method, Asaoka's method, hyperbolic method, ${\sqrt{s}}$ method and Monden's method were used to investigate their applicability and the inverse method of finding the soil parameter related to consolidation was used to predict the consolidation behavior in the future. It was confirmed that reliable prediction of consolidation behavior under various conditions could be done to estimate soil parameter related to consolidation such as the consolidation index and consolidation coefficient by the inverse method of comparing the measured settlement with the predicted value by the settlement prediction methods.

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Model Tests for Vertical Loads Acting on Embankment Piles (성토지지말뚝에 작용하는 연직하중에 대한 모형실험)

  • 홍원표;강승인
    • Journal of the Korean Geotechnical Society
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    • v.16 no.4
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    • pp.171-181
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    • 2000
  • A series of model tests were performed both to investigate the load transfer by soil acrching in fills above embankment pils and to verify of the theoretical analysis. In the model tests, the piles were installed in a row below the embankment and the cap beams were placed on the pile heads perpendicular to the longitudinal axias of the embankment. The space between pile cap beams and the embankment height was focused as the major factors affecting the load transfer in embankment fill. When the embankment fill was higher than the minimum required height, which was about 33% higher than the radius of the soil arch proposed by theoretical discussion in the previous study, not only the soil arching could be developed completely but also the experimental results showed good agreement with theoretical predictions. The portion of the embankment load carried by model pile cap beams decreased with increment of the space between pile cap beams, while it increased with increment of the embankment height. Therefore, to maximize the effect of embankment load transfer by piles on design, the interval ratio of pile cap beams should be decreased under considerably high embankments by reducing the space between cap beams and/or enlarging the width of pile cap beams.

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Design of geocell reinforcement for supporting embankments on soft ground

  • Latha, G. Madhavi
    • Geomechanics and Engineering
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    • v.3 no.2
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    • pp.117-130
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    • 2011
  • The methods of design available for geocell-supported embankments are very few. Two of the earlier methods are considered in this paper and a third method is proposed and compared with them. In the first method called slip line method, plastic bearing failure of the soil was assumed and the additional resistance due to geocell layer is calculated using a non-symmetric slip line field in the soft foundation soil. In the second method based on slope stability analysis, general-purpose slope stability program was used to design the geocell mattress of required strength for embankment. In the third method proposed in this paper, geocell reinforcement is designed based on the plane strain finite element analysis of embankments. The geocell layer is modelled as an equivalent composite layer with modified strength and stiffness values. The strength and dimensions of geocell layer is estimated for the required bearing capacity or permissible deformations. These three design methods are compared through a design example. It is observed that the design method based on finite element simulations is most comprehensive because it addresses the issue of permissible deformations and also gives complete stress, deformation and strain behaviour of the embankment under given loading conditions.

Lateral Displacement and Ground Rising Movement with Soil Embankment (성토에 따른 지반의 측방변위와 지표면 융기량)

  • Jeong, Ji-Cheol;Shin, Bang-Woong;Oh, Se-Wook
    • Journal of the Korean GEO-environmental Society
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    • v.5 no.2
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    • pp.63-69
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    • 2004
  • During and after the construction of embankment on soft ground, consolidation settlements and lateral displacements develop. But generally it's very difficult to predict the magnitude of lateral deformations and the correct distribution of lateral displacements with depth under the toe of embankment because the consolidation and the shear deformations of soft ground occur simultaneously. This study shows that later displacements of ground surface arise by embankment loading act on soft clay hight water contents in laboratory model testing. The results of model test are observed settlement of embankment, amount of maximum rising and displacement of ground surface with loading velocity. The formula were proposed to predict lateral movement by test series.

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Instrumentations for the Behaviour Observation of the Geotextile on Marine Clayey Grounds (해성점토지반에 설치된 지오텍스타일의 거동 관측을 위한 계측)

  • 조성민;장용채
    • Journal of Korean Port Research
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    • v.14 no.4
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    • pp.463-473
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    • 2000
  • Reinforcement with geotextiles have been used in the foundation soil to enhance the resistance of embankments to avoid failure through excessive deformation or shear in the foundation. It is improtant to know the amount of the strain and the displacement of buried geotextiles for the verification of the reinforcement behaviour. Full scale trial constructions were performed to check the deformational characteristics of the polyester(PET) mat which was used for the embankment reinforcement. Many instrumentation equipments including surface settlement plates, profile gauges and inclinometer casings were installed to observe the behaviour of the soft ground due to the soil embankment. 60 electrical resistance strain gauges and 9 vibrating wire LVDTs were installed 세 measure the deformation of the polyester mat. Results of various tests and geotextile, waterproofing and protection from the hazard environments were introduced. The proposed instrumentation method was effective for the monitoring or the geotextile behaviour. The direct attachment of electrical resistance strain gauges on the gertextile mat was able to measure small changes of the strain of geotextiles. At the end of the 5 month monitoring, 54 of 60 (93%) strain gauges and 7 of 9 (78%) displacement transducers survived all perils of the compaction impacts and the humidity. And the tensile strain of grotextiles increased as the ground displacement became larger. Though the observed strain of mats under the 3m high embankment load was less than 1%, the magnitudes of the strain according to the mat spreading method were different from each other.

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Wave Propagation Analysis for Pile-Slab Section on High Speed Railway (고속철도 파일슬래브공법 적용구간에서의 파전파해석)

  • Lee, Kang-Myung;Lee, Il-Wha
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.3201-3207
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    • 2011
  • This paper reviewed wave propagation of train vibration based on the study of high speed railway soft ground section with pile slab construction. In a filed of railway, concrete track has been adapted in a railway construction. And in order to maintain its track, soil improving method was required to control residual settlement. Within many soft ground settlement prevention techniques, pile slab method has an effect of minimizing residual settlement of soft ground. This is possible using support embankment load method by construct pile slab or cap the upper soft ground. This paper reviewed vibration wave characteristic of soft ground section with pile slab using numerical analysis application through finite element analysis. Pile slab method is established between high stiffened soft ground and embankment this creates a possibility of vibration block or slab amplification. Thus analyzed of wave propagation was done with roadbed and structure property to confirm application performance of pile slab method of high speed railway structure.

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A Case of Field Application of EPS Blocks and Its Performance (EPS블럭의 현장적용에 따른 하부지반의 거동 연구)

  • 장용채
    • Geotechnical Engineering
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    • v.14 no.1
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    • pp.15-28
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    • 1998
  • The use of EPS application to construction field was introduced in this country very recently. Nevertheless, approximately a total of 210,000m3 of EPS application was conducted in less than four years. Main app.lication areas for the EPS method are : (1)backfill behind a bridge abutment constructed on soft clay soil, (2)embankment constructed on soft clay soil, and (3)backfill of gravity wall. Among these, about 70oA of EPS are used for (1) and (2) deb cribed above. In this study, an invesitgation was held for the application of the EPS method to backfill of a bridge abutment which was constructed on soft clay soil. Several instruments were installed around the construction site to invesitgate the behavior of the system. Then a Finite Element Analysis was conducted for comparison.

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A Development of Automated Monitoring Technique and Feedback Design System for Embankment on Soft Ground (연약지반 계측 정보관리 및 자동분석.재설계 시스템 개발)

  • 한영철;윤동덕;김주용
    • Proceedings of the Korean Geotechical Society Conference
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    • 1999.10a
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    • pp.103-108
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    • 1999
  • This paper describes development of a new automated real-time system which preforms measurement data reduction and management, geotechnical backanalysis, and feedback design for embankment construction on soft ground. Such a system can be an effective, useful and economical tool for managing a large site development on soft ground. The system consists of data base system to characterize soil properties and identify instrumentation, analysis system for ground behavior and stability coupled with automatic monitoring system, and feedback design system which is a new technique to reflect the analysis of measured ground behavior against original design.

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Characteristics of Lateral Flow due to Embankments for Road Construction on Soft Grounds Using Vertical Drain Methods (연직배수공법이 적용된 연약지반 상에 도로성토로 인한 측방유동의 특성)

  • Hong, Won-Pyo;Kim, Jung-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.28 no.9
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    • pp.5-15
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    • 2012
  • Field monitoring data for embankments in thirteen road construction sites at coastal area of the Korean Peninsula were analyzed to investigate the characteristics of lateral flow in soft grounds, to which vertical drain methods were applied. First of all, the effect of the embankment scale on the lateral flow was investigated. Thicker soft soils and lager relative embankment scale produced more horizontal displacements in soft grounds. Especially, if thick soft grounds were placed, the relative embankment scale, which was given by the ratio of thickness of soft ground to the bottom width of embankments, became larger and in turn large horizontal displacement was produced. And also higher filling velocity of embankments induced more horizontal displacements in soft grounds. The other major factors affecting the lateral flow in soft ground were the thickness and undrained shear strength of soft grounds, the soil modulus and the stability number. Maximum horizontal displacement was induced by less undrained shear strength and soil modulus of soft grounds. Also more stability numbers produced more maximum horizontal displacements. When the shear deformation does not develop, the stability number was less than 3.0 and the safety factor of bearing was more than 1.7. However, if the stability number was more than 5.14 and the safety factor of bearing was less than 1.0, the unstable shear failure developed in soft ground. 50mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear deformation in soft ground, while 100mm can be recommended as a criterion of the allowable maximum horizontal displacement to prevent the shear failure in soft ground.

Model Test on the Effect of the Depth of Revetment by Inter Sand Layer in Soft Ground (모형토조 실험을 이용한 연약지반내 중간모래층이 호안제방하부 강제치환 깊이에 미치는 영향 연구)

  • Chung, Hyung-Sik;Bang, Chang-Kuk;Lee, Yong-Jun
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.956-965
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    • 2005
  • In this paper, the effect on the forced replacement depth of the revetment in soft soil with inter sand layer is analyzed by model test. In the result, the forced replacement occur in 60 second from filling the embankment material. The shape of the forced replacement depth is like to punching shape. Then, in case of thin inter sand layer and near the embankment, the forced replacement depth of inter sand layer case is more than only clayed soil case.

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