Centrifuge Modeling of Granular Soil Response Over Active Circular Trapdoors

Dewoolkar, Mandar M.; Santichaianant, Kitidech; Ko, Hon-Yim

doi:10.3208/sandf.47.931

Cited by 80 publications

(27 citation statements)

References 17 publications

(22 reference statements)

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“…(a) The variation of ground reaction curves with relative tunnel depth and soil density was in general agreement with trapdoor centrifuge tests reported by Dewoolkar et al (2007) and Iglesia et al (2014). However, in contrast to the trapdoor results, it was shown that the greater the cover-to-diameter ratio (C/D) and/or the looser the soil, the higher the tunnel volume loss corresponding to the minimum tunnel pressure.…”

Section: Discussionsupporting

confidence: 72%

“…With respect to the trapdoor-based findings of Dewoolkar et al (2007) and Iglesia et al (2014), the results in Fig. 2 confirm that minimum relative loadings (σ t,min /σ t,0 ) decrease with the increase of C/D and that σ t,min slightly decreases with the increase in I d .…”

Section: Ground Reaction Curvessupporting

confidence: 70%

“…the ground reaction curve (GRC)) is also of interest. GRCs for tunnels in cohesionless soils were suggested and compared against numerical analyses by Wong & Kaiser (1991), whereas Dewoolkar et al (2007) and Iglesia et al (2014) conducted investigations based on centrifuge modelling of a trapdoor. There have not been extensive centrifuge test investigations of the GRC for tunnels in cohesionless soils.…”

Section: Experimental Set-up and Spin-up Effectsmentioning

confidence: 99%

See 2 more Smart Citations

Greenfield tunnelling in sands: the effects of soil density and relative depth

2019

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Tunnel construction is vital for the development of urban infrastructure systems throughout the world. An understanding of tunnelling-induced displacements is needed to evaluate the impact of tunnel construction on existing structures. Recent research has provided insight into the complex mechanisms that control tunnelling-induced ground movements in sands; however, the combined influence of relative tunnel depth and soil density has not been described. This paper presents data from a series of 15 plane-strain centrifuge tests in dry sand. The cover-to-diameter ratio, C/D, of the tunnels ranges between 1·3 and 6·3, thereby including relatively shallow and deep tunnels. The sand relative density varies between 30 and 90%, corresponding to loose and dense soils. The effects of C/D, soil density and volume loss on vertical and horizontal soil movements, shear strains and ground reaction curves are discussed. Analysis of surface and subsurface settlement trough characteristics shows that the mechanisms are non-linear and the effects of soil relative density and volume loss on deformation patterns are highly dependent on C/D. The role of soil arching in the definition of the displacement mechanisms and a discussion of the implications of the results to the assessment of damage to existing structures are also provided.

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Section: Discussionsupporting

confidence: 72%

Section: Ground Reaction Curvessupporting

confidence: 70%

Section: Experimental Set-up and Spin-up Effectsmentioning

confidence: 99%

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Greenfield tunnelling in sands: the effects of soil density and relative depth

2019

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“…Iglesia et al made a similar conclusion from centrifuge model tests and presented the expressions of earth pressure acting on the trapdoor corresponding to these three phases. Dewoolkar et al investigated the failure mechanisms of soil mass above a trapdoor with different buried depth and stress levels through the axisymmetric centrifuge model tests. Costa et al conducted a similar study with centrifuge model tests under plane strain condition.…”

Section: Introductionmentioning

confidence: 99%

Numerical and theoretical research on stress distribution in the loosening zone of the trapdoor problem

Liang

2019

Num Anal Meth Geomechanics

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Summary The traditional theory of soil arching effect was developed on the assumption that stress distribution in the loosening zone is uniform. However, because of the deflection of principal stress' direction, the stress distribution in the loosening zone is actually ununiform. For the evaluation of principal stress axis deflection and stress redistribution, a discrete element method numerical model of trapdoor problem is established for the simulation of soil arching effect. Based on the numerical results, an arc shape of major principal stress trajectory and uniform horizontal stress distribution at the same depth of the loosening zone are adopted. An analytical model is raised to estimate the average loosening earth pressure acting on the trapdoor and stress distribution in the loosening zone at a limit state. In addition, comparison studies are carried out between the predictions of the proposed solutions and discrete element method numerical results as well as available model test results, thereby validating the accuracy of the proposed theoretical model. Both numerical and theoretical results indicate that the vertical stress distribution in the loosening zone is obviously ununiform. The load acting in the middle of loosening zone is transferred toward two sides so that the vertical stress distribution in loosening zone is concave.

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“…The trapdoor problem has been investigated ex-perimentally and theoretically by many researchers. Dewoolkar et al (2007) listed the major experimental studies on trapdoors with diŠerent testing conditions. Most of these studies were performed under plane strain (strip trapdoors) or axisymmetric conditions (circular trapdoors) (Terzaghi, 1936;Tanaka and Sakai, 1993;Vardoulakis et al, 1981;Dewoolkar et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Arching Observation in Three-Dimensional Trapdoor Problem with X-Ray CT and Discrete Element Method

Chevalier

Otani

2011

Soils and Foundations

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A comparative study of the trapdoor problem is proposed in this paper involving experimental model tests on one side and a Discrete Element Method modelling on the other side. Most of the past studies related to the arching eŠect and the trapdoor problem were performed under plane strain or axisymetric conditions. The observation of the arching mechanisms is indeed simpliˆed under these special test conditions. In this paper, the trapdoor problem was simulated under three-dimensional testing conditions with a square-shaped trapdoor. The granular layers were made with monodisperse glass beads. The arching mechanisms were experimentally investigated with X-ray Computed Tomography. Based on the images obtained, the propagation in the granular layer of the disturbance due to the displacement of the trapdoor was monitored. On the other side, the intensity of the load transfers in the granular material was evaluated with a force measurement apparatus on the trapdoor. In parallel, a numerical analysis involving the Discrete Element Method was conducted to predict both the qualitative and the quantitative phenomena. The gradual local expansion of the granular layer due to trapdoor displacement and the load transfer amplitudes were very well reproduced. An agreement between the experimental and the numerical results was obtained for small displacements of the trapdoor (high load transfers) as well as for larger displacements of the trapdoor.

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Centrifuge Modeling of Granular Soil Response Over Active Circular Trapdoors

Cited by 80 publications

References 17 publications

Greenfield tunnelling in sands: the effects of soil density and relative depth

Greenfield tunnelling in sands: the effects of soil density and relative depth

Numerical and theoretical research on stress distribution in the loosening zone of the trapdoor problem

Arching Observation in Three-Dimensional Trapdoor Problem with X-Ray CT and Discrete Element Method

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