• Title/Summary/Keyword: Nonlinear active earth pressure

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Estimation of 3D active earth pressure under nonlinear strength condition

  • Zhang, D.B.;Jiang, Y.;Yang, X.L.
    • Geomechanics and Engineering
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    • v.17 no.6
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    • pp.515-525
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    • 2019
  • The calculation of active earth pressure behind retaining wall is a typical three-dimensional (3D) problem with spatial effects. With the help of limit analysis, this paper firstly deduces the internal energy dissipation power equations and various external forces power equations of the 3D retaining wall under the nonlinear strength condition, such as to establish the work-energy balance equation. The pseudo-static method is used to consider the effect of earthquake on active earth pressure in horizontal state. The failure mode is a 3D curvilinear cone failure mechanism. For the different width of the retaining wall, the plane strain block is inserted in the symmetric plane. By optimizing all parameters, the maximum value of active earth pressure is calculated. In order to verify the validity of the new expressions obtained by the paper, the solutions are compared with previously published solutions. Agreement shows that the new expressions are effective. The results of different parameters are given in the forms of figures to analysis the influence caused by nonlinear strength parameters.

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.

Active Earth Pressure behind Rigid Retaining Wall Rotating about the Base (저점을 중심으로 회전하는 강성옹벽에 작용하는 주동토압)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.20 no.8
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    • pp.193-203
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    • 2004
  • Arching effects in backfill materials generate a nonlinear active earth pressure distribution on a rigid retaining wall with rough face, and arching effects on the shape of the nonlinear earth pressure distribution depends on the mode of wall movement. Therefore, the practical shape of failure surface and arching effect in the backfill changed with the mode of wall movement must be considered to calculate accurate magnitude and distribution of active earth pressure on the rigid wall. In this study, a new formulation for calculating the active earth pressure on a rough rigid retaining wall rotating about the base is proposed by considering the shape of nonlinear failure surface and arching effects in the backfill. In order to avoid mathematical complexities in the calculation of active earth pressure, the imaginary failure surface composed of four linear surfaces is used instead of the nonlinear failure surface as failure surface of backfills. The comparisons between predictions from the proposed equations and existing model test results show that the proposed equations produce satisfactory predictions.

Nonlinearly Distributed Active Earth Pressure on n Translating Rigid Retaining Wall : I. Formulation (평행이동하는 강성옹벽에 작용하는 비선형 주동토압 : I. 정식화)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.19 no.1
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    • pp.181-189
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    • 2003
  • The active earth pressure against a rigid retaining wall has been generally calculated using either Rankine's or Coulomb's formulation. Both assume that the distribution of active earth pressure exerted against the wall is triangular. However, many experimental results show that the distribution of the active earth pressure on a rigid rough wall is nonlinear. These results do not agree with the assumption used in both Rankine's and Coulomb's theories. The nonlinearity of the active earth pressure distribution results from arching effects in the backfill. Several researchers have attempted to estimate the active earth pressure on a rigid retaining wall, considering arching effect in the backfill. Their equations, however, have some limitations. In this paper, a new formulation for calculating the active earth pressure on a rough rigid retaining wall undergoing horizontal translation is proposed. It takes into account the arching effects that occur in the backfill.

Estimation of Nonlinearly Distributed Active Earth Pressure on Rigid Retaining Wall (강성옹벽에 작용하는 비선형 주동토압의 산정)

  • 백규호
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.443-450
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    • 2002
  • It is known that the distribution of the active earth pressure against a translating rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the present paper, a new formulation for calculating the active earth pressure on a rigid retaining wall undergoing horizontal translation is proposed. It takes into account the arching effects that occur in the backfill. 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 total active earth force on the translating wall.

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Active Earth Pressure against Caisson Backfilled with Crushed Rock and Sand (I) : Formulation (사석과 모래로 뒷채움된 케이슨에 작용하는 주동토압 (I) : 정식화)

  • Paik Kyu-Ho
    • Journal of the Korean Geotechnical Society
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    • v.22 no.1
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    • pp.63-72
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    • 2006
  • Coulomb's theory has traditionally been used for the estimation of active earth pressure acting on rigid walls. However, many experimental data show that active earth pressures on rough, rigid walls are nonlinearly distributed. This is due to the arching effects produced by friction between the wall and backfill materials when the wall translates away from the backfill. Although there are analyses that take arching into consideration f3r a horizontal backfill surface and a vertical rigid wall, these analyses were derived for homogeneous backfill. Therefore, it is not possible to use these analyses for a caisson backfilled with crushed rock and sand, a common type of rigid wall for harbor structures. In this study, a new formulation for calculation of the nonlinear active earth pressure acting on a caisson backfilled with crushed rock and sand is proposed considering both internal friction angles and unit weights of the crushed rock and sand.

Active Eanh Pressure Against Caisson Backfilled with Crushed Rock and Sand (II) : Verification and Application (사석과 모래로 뒷채움된 케이슨에 작용하는 주동토압 (II) : 검증과 적용)

  • Paik Kyu-Ho
    • Journal of the Korean Geotechnical Society
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    • v.22 no.2
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    • pp.29-39
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    • 2006
  • In the companion paper (Paik 2006), a new formulation for calculating the nonlinearly distributed active earth pressure acting on a caisson backfilled with crushed rock and sand is proposed, and it takes into account arching effects as well as difference in internal friction angles and unit weights between sand and crushed rock. In this study, in order to partially check the accuracy of the proposed equation, the results of the proposed equation are compared with the equation proposed by Paik (2003a) for caissons with rough surface and homogeneous backfill, and are compared with results of Rankine's theory for caissons with smooth surface and homogeneous backfill. In addition, a parametric study is performed to investigate the effect of $phi_{r}$, $phi_{s}$, $\delta_{r}$, $\gamma_{r}$, $\gamma_{s}$ and $\beta$ on the magnitude of active earth pressure acting on the caisson, and construction methods for minimizing active earth pressure on the caisson are also provided based on the results of a parametric study.

Seismic Fragility Evaluation of Inverted T-type Wall with a Backfill Slope Considering Site Conditions (사면 경사도가 있는 뒷채움토와 지반특성을 고려한 역T형 옹벽의 지진시 취약도 평가)

  • Seo, Hwanwoo;Kim, Byungmin;Park, Duhee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.41 no.5
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    • pp.533-541
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    • 2021
  • Retaining walls have been used to prevent slope failure through resistance of earth pressure in railway, road, nuclear power plant, dam, and river infrastructure. To calculate dynamic earth pressure and determine the characteristics for seismic behavior, many researchers have analyzed the nonlinear response of ground and structure based on various numerical analyses (FLAC, PLAXIS, ABAQUS etc). In addition, seismic fragility evaluation is performed to ensure safety against earthquakes for structures. In this study, we used the FLAC2D program to understand the seismic response of the inverted T-type wall with a backfill slope, and evaluated seismic fragility based on relative horizontal displacements of the wall. Nonlinear site response analysis was performed for each site (S2 and S4) using the seven ground motions to calculate various seismic loadings reflecting site characteristics. The numerical model was validated based on other numerical models, experiment results, and generalized formula for dynamic active earth pressure. We also determined the damage state and damage index based on the height of retaining wall, and developed the seismic fragility curves. The damage probabilities of the retaining wall for the S4 site were computed to be larger than those for the S2 site.