• Title/Summary/Keyword: earth wall

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Problem of Evaluation Methods on the Wall Facing-Geosynthetics Connection Strength and Its Improvement (전면 벽체-보강재 연결강도 평가방법의 문제점 및 개선 방향)

  • Hong, Ki-Kwon;Shin, Ju-Oek;Han, Jung-Geun;Cho, Sam-Deok;Lee, Kwang-Wu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.184-195
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    • 2008
  • The use of geosynthetics for the reinforced earth wall system has been increasing rapidly for a number of years. The connection strength between wall facing and geosynthetics should be evaluated in the design of geosynthetics. However, the connection strength is not often evaluate, exactly, and it causes problems such as deformation of the wall facing, local failure of the reinforced earth wall system, conservative design and so on. Therefore, the connection strength in the design of geosynthetics should be applied evaluation result by reasonable method. This study is evaluated connection strength using the typical design method, NCMA(1997) and FHWA(1996), in the field case. Then the results compared with the evaluation results of connection strength, which is suggested by Soong & Koener(1997). The analysis results confirmed that the connection strength for the design of geosynthetics should be evaluate using reasonable method with considering various factor, such as safety factor, installation and importance of construction.

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The 3-Dimensional Active Earth Pressure Depending on the Size of Rectangular Wall (직사각형 벽체의 크기에 따른 3차원 주동토압)

  • Park, Byung-Suk;Lee, Sang-Duk
    • Journal of the Korean Geotechnical Society
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    • v.31 no.9
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    • pp.69-78
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    • 2015
  • If an active displacement occurs on a wall with finite size, the ground behind the wall forms shapes of 3-dimensional wedges and 3-dimensional active earth pressure are applied on the wall. In the previous studies, shapes of 3-dimensional wedges were measured and the resultant of 3-dimensional active earth pressure has been calculated. In this study, the magnitude and the distribution of 3-dimensional active earth pressure depending on the size of a rectangular wall, which was defined by the aspect ratio (h/w), that is, the ratio between the height and the width of wall, were measured and compared with previous 3-dimensional models. The result shows that, the horizontal displacement (S) of the wall is approx 0.12% of the height of wall (h). The resultant 3-dimensional active earth pressure is similar to that of Karstedt (1982). The distributions of earth pressures on the wall are parabolic shape. The peak earth pressure was measured at the 0.5~0.55 depth from the ground surface. The reduction factor of 3-dimensional active earth pressure against the 2-dimensional earth pressure (${\alpha}$) depending the aspect ratio (h/w) is presented by the diagram.

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.

Behaviour of Reinforced Earth Wall with Steel Framed-Facing based on Field Test (현장시험을 이용한 강재틀 보강토옹벽의 안정성 평가)

  • Lee, Kwang-Wu;Cho, Sam-Deok;Han, Jung-Geun;Hong, Ki-Kwon
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.4
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    • pp.37-47
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    • 2011
  • This paper describes the stability evaluation of reinforced earth wall with steel framed-facing based on field test. The reinforced earth wall with steel framed-facing is composed of wall facing, reinforcement and backfill soil. The wall facing is assembled by steel frames and the aggregates are filled in that. The reinforcement is steel strip type based on bearing resistance. Field test is conducted to evaluate for two separate sections and the measurement is conducted according to construction elapsed time of structure for earth pressure, horizontal displacement of wall facing and reinforcement strain. The evaluation results show that the measured earth pressure is less than theoretical earth pressure due to dispersion effect of earth pressure by the applied reinforcement. Also, the horizontal displacement of wall facing satisfied a empirical criteria and the measured strain of reinforcement had nearly no effect on stability of structure. Therefore, the reinforced earth wall with steel framed-facing has a structural stability and it can be commonly used in field.

Nonlinearly Distributed Active Earth Pressure on a Translating Rigid Retaining Wall : II. Application (평행이동하는 강성옹벽에 작용하는 비선형 주동토압 : II. 적용성)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.19 no.1
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    • pp.191-199
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    • 2003
  • It is known that the distribution of the active earth pressure against a rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the farmer paper, a new formulation was proposed for the nonlinear distribution of active earth pressure on a translating rigid retaining wall considering arching effects. In this paper, parametric study is performed to investigate the effect of ${\phi}, {\delta}$ and wall height on the magnitude and distribution of active earth pressure calculated from the proposed equations. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the lateral active earth force on the translating wall. Simplified design charts are also proposed for the modified active earth pressure coefficient and fur the height of application of the lateral active force in order to facilitate the use of the proposed equation.

Numerical Analysis for Lateral Earth Pressure on Retaining Wall with Relieving Platform backfilled with Jumoonjin Sand (주문진 모래로 뒤채움한 선반식 옹벽의 수평토압에 관한 수치해석)

  • Moon, In-Jong;Kim, Byoung-Il;Yoo, Wan-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3916-3922
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    • 2014
  • Generally, the retaining wall is becoming unstable as the height is higher. On the other hand, the retaining wall with the relieving platform is more stable and more economical than any other type of retaining wall, because the relieving platform the reduce the lateral earth pressure. In this study, numerical analyses were carried out for 15 cases varying with the type of retaining wall, length and location of the relieving platform and the backfill type. From the numerical analyses, the reduction of the lateral earth pressure was checked and the results of numerical analyses were compared with that of model tests and theoretical equations. As the results of this study, the lateral earth pressure of the retaining wall with the relieving platform is considerably less than that of cantilever wall. And the of magnitude of the lateral earth pressure is affected by the length and location of relieving platform and the backfill type.

Earth Pressure on the Cylindrical Wall in Cohesionless Soils (사질토 지반의 원형수직구에 설치된 흙막이벽에 작용하는 토압)

  • 천병식;신영완
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.175-187
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    • 2003
  • The earth pressure acting on the cylindrical retaining wall in cohesionless soils is different from that on the retaining wall in plane strain condition due to three dimensional arching effect. Accurate estimation of earth pressure is required for the design of vertical cylindrical retaining wall. Failure modes of the ground behind vertical shaft are dependent on ground in-situ stress conditions. Failure modes are actually divided into two modes of cylindrical failure mode and funnel-shaped mode with truncated cone surface. Several researchers have attempted to estimate the earth pressure on cylindrical wall for each failure mode, but they have some limitations. In this paper, several equations for estimating the earth pressure on cylindrical wall in cohesionless soils are investigated and new formulations for two failure modes are suggested. It rationally takes into account the overburden pressure, wall friction, and force equilibriums on sliding surface.

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).

The Behavior of Earth Retaining Walls Applied to Top-Down Construction Method Using Back Analysis (Top-Down 공법이 적용된 흙막이벽의 역해석을 이용한 거동분석)

  • Hong, Won-Pyo;Kang, Chul-Joong;Yun, Jung-Mann
    • The Journal of Engineering Geology
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    • v.22 no.1
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    • pp.39-48
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    • 2012
  • The behaviors of a diaphragm wall and a contiguous pile wall such as CIP(Case-in-place pile) and SCW(Soil-cement wall), applied to the top-down construction method, were analyzed using the SUNEX program, which is widely used to design earth retaining walls. Four types of earth pressures, as described by Rankine (1857), Terzaghi and Peck (1967), Tchbotarioff (1973), and Hong and Yun (1995a), were applied to the analysis program to predict the lateral displacement of walls. The results show that the displacements of an earth retaining walls vary with the applied earth pressure. The predicted lateral displacement based on Hong & Yun's (1995a) earth pressure is similar to the measured displacement. Therefore, the actual lateral displacement of an earth retaining wall, as applied to top-down construction method, can be accurately predicted by using an analysis program considering Hong and Yun's (1995a) earth pressure.