• Title, Summary, Keyword: Improved trial wedge

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Stability of Railway Bridge Abutment with Earth Pressure and Internal Friction Angle of Backfill (내부마찰각과 토압 산정방법에 따른 철도교대의 안정성 비교 연구)

  • Choi, Chan Yong;Kim, Hun Ki;Yang, Sang Beom;Kim, Byung Il
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.765-776
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    • 2016
  • In this study, a standard section of a railway bridge abutment wall was designed to satisfy the external stability condition in accordance with the design criteria; this design was used to compare and analyze the active earth pressure and to calculate various types of earth pressure acting on the virtual back (wall, plane) according to the frictional angle of the backfill materials. Also, the external stability, member force and construction cost were analyzed according to the frictional angle of the backfill materials using various theories of earth pressure such as Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge. As for the results, it was found that lateral earth pressure at the virtual back plane was higher than at the virtual back wall, and that these values decreased with the increase of the frictional angle of the backfill materials. The increasing of the frictional angle of the backfill materials decreased the active earth pressure (according to Rankine, Coulomb, Trial Wedge, and Improved Trial Wedge results), and the member force as well as the construction cost were reduced.

An Estimation of Behavior for Wedge type Removable Soil Nailing System by Field Trial Construction (현장시험시공을 통한 쐐기형 제거식 쏘일네일링 공법의 거동 평가)

  • Han, Yeon-Jin;Park, Si-Sam;Kwon, Hyuk-Jun;Kim, Hong-Taek;Park, Ju-Seok
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1360-1364
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    • 2009
  • Necessity of removable soil nailing has been arisen in the soil nailing system because of problem such as civil petition for geotechnical environment and invasion of the ground boundary line and payments for use besides geotechnical engineering. Removable soil nailing system is improved soil nailing system that fixed socket arranged in boring hole for increasement of skin friction. In this study, field pull-out tests are carried out more 4 times considering installed distance of fixed socket and analyze skin friction behavior characteristics in fixed socket through analysis of measurements of strain gauge attached to fixed socket. Also, to evaluate application for wedge type removable soil nailing system analyzing displacement aspects through field pull-out tests by trial construction.

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The Calculation and Design Method of Active Earth Pressure with Type of Gravity Structures (중력식 구조물의 형태에 따른 주동토압 산정과 설계법 제안)

  • Kim, Byung-Il;Jeong, Young-Jin;Kim, Do-Hyung;Lee, Chung-Ho;Han, Sang-Jae
    • Journal of the Korean Geotechnical Society
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    • v.30 no.4
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    • pp.47-63
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    • 2014
  • In this study theories of earth pressure such as Rankine, Coulomb, Trial Wedge, Improved Trial Wedge, used in the design for onshore and offshore structures, are analyzed and the characteristics of loaded pressure to virtual back (wall, plane) and wall surface in accordance with the structure type are suggested. To investigate characteristics of earth pressure, gravity retaining wall with inclined angle and cantilever wall with inclined ground are movilized for onshore structures and caisson and block type quay wall are mobilized for offshore structures. Based on various theories, the earth pressure applied angle(wall friction angle) and sliding angle toward the wall, which is influenced by the heel length, are calculated and compared. In the case of long heel, the pressure by Rankine's method in virtual plane and the mobilized angle are most reasonably estimated by the ground slope, and in the case of short heel, the pressure by Coulomb's method and the mobilized angle by the angle of wall friction. In addition, the sliding angle toward the wall estimated by the improved trial wedge method is large than the value of Rankine's method. Finally, in this study the reasonable method for calculating the pressure and the mobilized angle that can be applied to the routine design of port structures is proposed. The proposed method can decide the earth pressure with length of a heel and a self weight of retaining wall according to sliding angle toward the wall.

An Experimental Study on the Improvement of Resistance Performance at Pre-planing Condition for G/T 100 ton Class Planing Hull Form (총톤수 100톤급 활주형선의 활주 전 저항성능 개선에 관한 실험적 연구)

  • Lee, Kwi-Joo;Joa, Soon-Won
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.1
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    • pp.17-22
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    • 2004
  • This study was carried out at the CWC of Chosun university for the purpose of resistance performance improvement of planing hull, and the results of the tests were confirmed cooperatively with WJFEL. G/T 100 ton class planing hull form was selected, and the improvement of hull form including appendages were performed by using some model test techniques. The model test scope comprises resistance relative tests including wave profile observation, trim and sinkage measurement and flow visualization tests at full load and trial conditions for one bare hull and for two appended hulls. The final wedge and spray strip combined with improved hull form showed about 1.0 knot speed improvement at both of full and trial conditions, and outstanding improvement for fore wave phenomena.