• Title/Summary/Keyword: retaining wall

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Numerical Analysis of Self-Supported Earth Retaining Wall with Stabilizing Piles (2열 자립식 흙막이 공법의 거동특성에 관한 수치해석적 연구)

  • Sim, Jae-Uk;Jeong, Sang-Seom;Lee, Jun-Hwan
    • Journal of the Korean Geotechnical Society
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    • v.31 no.5
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    • pp.35-46
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    • 2015
  • In this study, the behavior of self-supported earth retaining wall with stabilizing piles was investigated by using a numerical study and field tests in urban excavations. This earth retaining wall can provide stable support against lateral earth pressures through its use of stabilizing piles that provide passive resistance to lateral earth pressures arising due to ground excavations. Field tests at two sites were performed to verify the performance of instrumented retaining wall with stabilizing piles. Furthermore, detailed 3D numerical analyses were conducted to provide insight into the in situ wall behavior. The 3D numerical methodology in the present study represents the behavior of the self-supported earth retaining wall with stabilizing piles. A number of 3D numerical analyses were carried out on the self-supported earth retaining wall with stabilizing piles to assess the results stemming from wide variations of influencing parameters such as the soil condition, the pile spacing, the distance between the front pile and the rear pile, and the pile embedded depth. Based on the results of the parametric study, the maximum horizontal displacement and the maximum bending moment significantly decreased when the retaining wall with stabilizing piles is used. Moreover, the horizontal displacement reduction effect of influencing parameters such as the pile spacing and the distance between the front pile and the rear pile is more sensitive in sandy soil, with a higher friction angle compared to clayey soil. In engineering practice, reducing the pile spacing and increasing the distance between the front pile and the rear pile can effectively improve the stability of the self-supported earth retaining wall with stabilizing piles.

A Case study on reinforced retaining wall backfilled by soil cement (쏘일시멘트 보강토옹벽 사례 연구)

  • Lee, Myung-Jae;Jang, Ki-Soo;Lee, Jin-Hwan;Paik, Min-Cheol
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.985-994
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    • 2004
  • The application of the reinforced retaining wall has increased in the last 10 years in Korea. The height of reinforced wall is generally limited to less than 15m. It has been reported that the reinforced wall higher than 10m should have higher strength reinforcement or should reduce the lateral earth pressure of the reinforced wall to secure the stability of the wall. In this study, the reinforced retaining wall was constructed 14m high, backfilled by a mixture of soil and cement and instrumented on the reinforcement elements. The instrumented reinforced wall was monitored during and after construction. Field monitoring result shows that a backfill by a mixture of soil and cement reduced the tensile stress developed on the reinforcing elements and the reinforced wall backfilled by a mixture of soil and cement performed successful.

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Development of Strengthening Method and Safety Analysis of Ecological Block and Vegetation Bank Protection (식생블록옹벽의 구조적 안전성 해석과 보강설계기법 연구)

  • Oh, Byung-Hwan;Cho, In-Ho;Lee, Young-Saeng;Lee, Keun-Hee
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.1
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    • pp.207-215
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    • 2003
  • Developed is a new environment-friendly concrete-block retaining wall system. The conventional analysis methods are not directly applicable because the proposed concrete-block wall system is made of by interlocking the blocks with shear keys. Therefore, the shear analysis as well as stability analysis have been conducted to secure the safety of block-wall system. Overall slope stability analysis was also performed. An appropriate strengthening method was developed to ensure the safety when the block-wall system is relatively high. The method of analysis for strengthening the concrete-block wall system was also proposed. The proposed environment-friendly concrete block retaining wall system shows reasonable safety and can be a good construction method for retaining walls and river bank walls.

Pseudo-dynamic approach of seismic earth pressure behind cantilever retaining wall with inclined backfill surface

  • Giri, Debabrata
    • Geomechanics and Engineering
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    • v.3 no.4
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    • pp.255-266
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    • 2011
  • Knowledge of seismic earth pressure against rigid retaining wall is very important. Mononobe-Okabe method is commonly used, which considers pseudo-static approach. In this paper, the pseudo-dynamic method is used to compute the distribution of seismic earth pressure on a rigid cantilever retaining wall supporting dry cohesionless backfill. Planar rupture surface is considered in the analysis. Effect of various parameters like wall friction angle, soil friction angle, shear wave velocity, primary wave velocity, horizontal and vertical seismic accelerations on seismic earth pressure have been studied. Results are presented in terms of tabular and graphical non-dimensional form.

Experimental study on the behavior of retaining wall according to underground excavation distance (지하굴착 이격거리에 따른 흙막이벽체 거동에 대한 실험적 연구)

  • Park, Jong-Deok;Ahn, Chang-Kyun;Kim, Do-Youp;Lee, Seok-Won
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.2
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    • pp.155-164
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    • 2016
  • The changes in earth pressure and ground settlement due to the underground excavation nearby the existing retaining wall according to the separation distance between underground excavation and retaining wall, were studied experimentally. A soil tank having 160 cm in length and 120 cm in height, was manufactured to simulate the underground excavation like tunnel by using 5 separated bottom walls. The variation of earth pressure was measured according to the excavation stages by using 10 separated right walls simulating the retaining wall. The results showed that the earth pressure was changed by the lowering of first bottom wall(B1), however the earth pressure was not changed significantly by the lowering of third bottom wall(B3) since B3 had sufficient separation distance from retaining wall. Lowering of first bottom wall(B1) induced the decrease of earth pressure in lower part of retaining wall, on the contrary, lowering of first bottom wall(B1) induced the increase of earth pressure in middle part of retaining wall proving the arching effect.

Influence of wall flexibility on dynamic response of cantilever retaining walls

  • Cakir, Tufan
    • Structural Engineering and Mechanics
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    • v.49 no.1
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    • pp.1-22
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    • 2014
  • A seismic evaluation is made of the response to horizontal ground shaking of cantilever retaining walls using the finite element model in three dimensional space whose verification is provided analytically through the modal analysis technique in case of the assumptions of fixed base, complete bonding behavior at the wall-soil interface, and elastic behavior of soil. Thanks to the versatility of the finite element model, the retained medium is then idealized as a uniform, elastoplastic stratum of constant thickness and semi-infinite extent in the horizontal direction considering debonding behavior at the interface in order to perform comprehensive soil-structure interaction (SSI) analyses. The parameters varied include the flexibility of the wall, the properties of the soil medium, and the characteristics of the ground motion. Two different finite element models corresponding with flexible and rigid wall configurations are studied for six different soil types under the effects of two different ground motions. The response quantities examined incorporate the lateral displacements of the wall relative to the moving base and the stresses in the wall in all directions. The results show that the wall flexibility and soil properties have a major effect on seismic behavior of cantilever retaining walls and should be considered in design criteria of cantilever walls. Furthermore, the results of the numerical investigations are expected to be useful for the better understanding and the optimization of seismic design of this particular type of retaining structure.

Stability Analysis of Reinforced Retaining Wall with Steel Supported Face (강재지주 전면판 보강토 옹벽의 안정성 평가)

  • Kim, Ki Il;Kim, Byoung Il;Lee, Yeong Saeng;Lee, Soon Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.2C
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    • pp.75-82
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    • 2011
  • Recently, a new reinforced retaining wall with light steel support face has been developed. In this study, full size in-situ test is carried out to investigate the stability of the new reinforced retaining wall. The lateral displacement of wall, lateral earth pressure, and settlement of the reinforced retaining wall are measured in the full size test. And numerical analysis by 3-D finite element method is also carried out to compare the test results with those of the analysis. From the full size in-situ test, the maximum lateral displacement of wall is 46mm(0.009H) and the maximum settlement is 21.5mm. And comparing these values with those of numerical analysis, it is confirmed that the new reinforced retaining wall with light steel support face is stable and applicable.

Numerical Analysis on Behavior of Cantilever Retaining Walls (캔틸레버 옹벽의 거동에 대한 수치해석적 연구)

  • Jang, In-Seong;Jeong, Chung-Gi;Kim, Myeong-Mo
    • Geotechnical Engineering
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    • v.12 no.4
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    • pp.75-86
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    • 1996
  • Current methods to estimate the earth pressure for retaining wall analysis are based on Rankine or Coulomb approaches, in which the soil mass behind wall is assumed to reach to failure state with sufficient lateral movements. Some of recent research works carried out by field measurements reveal that the active earth. pressures by Ranking or Coulomb method are underestimated. It means that the lateral movements of wall and soil would not be mobilized enough to reach the failure state. In this study, the finite element method with Drucker -Prager model for soil is employed to investigate the behavior of concrete cantile,tier retaining wall, together with the influence of inclined backfill. The results indicate that the earth pressures on the retaining wall are strongly related to the mobilized lateral movements of wall and soil and that Ranking and Coulomb methods underestimate the resultant earth pressures and the increasing effect on earth pressure by inclined backfill. Based on this study, a simplified method to determine to earth pressures on cantilever retaining wall with horizontal backfill is proposed.

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Optimal Design Conditions of Retaining Wall with Relieving Platform through Real-Scale Numerical Analysis (실단면 수치해석을 통한 선반식 옹벽의 최적 설계 조건)

  • Moon, In-Jong;Kim, Byoung-Il;Han, Jin-Tae;Stuedlein, Armin W.
    • Journal of the Korean Geotechnical Society
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    • v.32 no.10
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    • pp.55-65
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    • 2016
  • Retaining wall with relieving platform has advantages in terms of stability and costs because it decreases the earth pressure by installing the relieving platform. However, there have not been previous studies of the optimal design for the retaining wall with reliving platform in practice. In this study, the optimal design conditions of the retaining wall with relieving platform are proposed by evaluating the reduction effect of lateral earth pressure based on the numerical analysis of 40 cross sections by changing wall types, wall heights, shelf locations and lengths. As a result, the optimal location of a shelf is the central part of a retaining wall (h/H=0.50) and the optimal length is recommended to be designed to satisfy b/L=0.45, at least.

Numerical Analysis for Optimum Reinforcement Length Ratio of Reinforced Earth Retaining Wall (보강토옹벽의 최적 보강길이비 산정을 위한 수치해석적 연구)

  • Park, Choonsik;Ahn, Woojong
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.12
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    • pp.5-14
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    • 2018
  • Recently, method of reinforced earth retaining wall have been proposed according to the material of facing, geosynthetic, construction method, and facing slope. However, the regulations such as the design method and detailed review items according to each construction method are not clear, and collapse due to heavy rainfall frequently occurs. In this study, to obtain a more stable technical approach in the design of reinforced earth retaining wall, the combination of the pullout failure of reinforced earth retaining wall and the optimal reinforcement ratio of height using reinforced earth retaining wall using a single strength reinforcement is assumed, optimum design of stiffener, optimal design of superimposed wall and optimum length ratio of reinforcement material of geosynthetics are proposed through safety factor according to reinforcement length ratio (L/H).