Three-Dimensional Active Earth Pressures for Unsaturated Backfills with Cracks Considering Steady Seepage

Zhang, Z. L.; Zhu, Jian-qun; Yang, Xiaohan

doi:10.1061/(asce)gm.1943-5622.0002648

Cited by 23 publications

(3 citation statements)

References 30 publications

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“…In the considered problem, the external work includes the following items: pore pressure, soil gravity, and slurry pressure. The calculation of the limit analysis is performed by equaling the internal energy dissipation rates and external work rates [35][36][37][38][39].…”

Section: Kinematical Analysis Of the Tunnel Facementioning

confidence: 99%

“…To balance the work rate equation, an index f σ representing the extra required uniform support pressure, in addition to the applied slurry pressure to maintain the tunnel face In the considered problem, the external work includes the following items: pore pressure, soil gravity, and slurry pressure. The calculation of the limit analysis is performed by equaling the internal energy dissipation rates and external work rates [35][36][37][38][39]. To balance the work rate equation, an index σ f representing the extra required uniform support pressure, in addition to the applied slurry pressure to maintain the tunnel face stability, is introduced.…”

Section: Kinematical Analysis Of the Tunnel Facementioning

confidence: 99%

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Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

et al. 2023

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With excess slurry pressures exerted on the tunnel face, slurry particles tend to infiltrate into the soil in front of the tunnel. There will be excess pore pressure ahead of the tunnel in the case of infiltration, leading to an impairment in the supporting effect contributed by the excess slurry pressure. Corresponding to three slurry infiltration scenarios distinguished by the forms of the filter cake, different pressure transfer models are employed to describe the pore pressure distribution. Using the kinematic approach of limit analysis and the numerically simulated seepage field, the study of tunnel face stability under different slurry infiltration cases is extended by employing a 3D discretization-based failure mechanism. In addition, two simple empirical formulas describing the pore pressure distributions above the tunnel and in advance of the tunnel are established and verified. Combined with the dichotomy method and strength reduction method, the safety factors yielding rigorous upper-bound solutions are obtained by optimization. The proposed method is validated by a comparative analysis. The developed framework allows considering the influence of excess pore pressure on the whole failure mechanism and the three-dimensional characteristics of seepage. A parameter analysis is performed to study the effect of the excess slurry pressure, hydraulic conditions, soil strength properties, and pressure drop coefficient. The results show that the steady-state flow model leads to much more conservative results than the full-membrane model. The safety factor increases with the increasing excess slurry pressure and the decreasing pressure drop coefficient. The present work provides an effective framework to quickly assess the face stability of tunnels under excess slurry pressure considering different filter cake scenarios.

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Section: Kinematical Analysis Of the Tunnel Facementioning

confidence: 99%

Section: Kinematical Analysis Of the Tunnel Facementioning

confidence: 99%

Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

et al. 2023

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“…The limit analysis method, relying on its rigorous and systematic theorem, has gradually been accepted by scholars and engineers in recent decades [14][15][16][17][18]. The difficulty of the lower-bound analysis exists in the establishment of the statically permissible stress field; for this reason, the construction of the appropriate stress field is generally performed with the help of finite element software.…”

Section: Introductionmentioning

confidence: 99%

Seismic Stability Analysis of Tunnel Faces in Heterogeneous and Anisotropic Soils Using Modified Pseudodynamic Method

2023

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This work assesses the seismic stability of tunnel faces advanced in heterogeneous and anisotropic soils based on the plastic limit theorem. A discretized kinematic velocity field respecting the normal flow rule is generated via a point-to-point discretization technique. The distribution of soil parameters in the depth direction including cohesion, friction angle, and unit weight are considered by four kinds of profiles. The variation in cohesion with shear direction caused by consolidation and sedimentation is considered by including an anisotropy coefficient. The seismic acceleration is represented by the modified pseudodynamic method (MPD) rather than the conventional pseudodynamic method (CPD). Based on the energy equilibrium equation, an upper-bound solution is derived. The accuracy and rationality of the proposed procedure are substantiated by comparing with the solutions obtained by conventional log-spiral mechanism and CPD. A parametric study indicates that nonlinear profiles tend to predict a smaller required face pressure than the constant and linear profiles due to the convexity of nonlinear profiles. The over-consolidated soil is more sensitive to the anisotropy coefficient than normally consolidated soil. Moreover, the adverse effect of horizontal seismic acceleration is much greater than that of vertical acceleration, and the resonance effect is more prone to happen, especially for shallow-buried tunnels.

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Seismic Stability of 3D Rock Slopes Based on a Multi-cone Failure Mechanism

2022

Rock Mech Rock Eng

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Three-Dimensional Active Earth Pressures for Unsaturated Backfills with Cracks Considering Steady Seepage

Cited by 23 publications

References 30 publications

Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

Tunnel Face Stability Considering the Influence of Excess Slurry Pressure

Seismic Stability Analysis of Tunnel Faces in Heterogeneous and Anisotropic Soils Using Modified Pseudodynamic Method

Seismic Stability of 3D Rock Slopes Based on a Multi-cone Failure Mechanism

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