Probabilistic basal heave stability analyses of supported circular shafts in non-homogeneous clayey soils

Abstract Circular shafts are commonly used to construct accesses to facilitate tunnel boring machine works and can be used as ventilation systems, subway stations or emergency exits. This study presents a probabilistic analysis of supported circular shafts in undrained and non-homogeneous clayey soils to reflect the uncertainty influences of the soil undrained shear strength at the ground surface, non-homogeneity coefficient, unit weight and soil-wall adhesion factor. The basal heave safety factor is evaluated by an axisymmetric lower bound Finite Element Limit Analysis and a probabilistic analysis is discussed using the adaptive Polynomial Chaos Kriging technique-based Monte-Carlo Simulation and a Global Sensitivity Analysis (GSA). After deterministic and probabilistic comparisons, academic cases are performed to get some insights for the following problems: (1) importance of the uncertainty’s consideration; (2) effect of the soil-wall interface; (3) influence of non-homogeneous soils on the circular shaft’s stability. Besides, some sensitivity analyses are conducted to discuss the input random variables importance. Obtained results show that the coefficient of variation, soil-wall adhesion factor and soil non-homogeneity coefficients have a remarkable influence on the circular shaft stability.

[1]  D. Dias,et al.  Influence of a weak layer on the tunnel face stability – Reliability and sensitivity analysis , 2020 .

[2]  Keizo Ugai,et al.  Base Stability of Circular Excavations in Soft Clay , 2002 .

[3]  A. Johari,et al.  System reliability analysis of soldier-piled excavation in unsaturated soil by combining random finite element and sequential compounding methods , 2020, Bulletin of Engineering Geology and the Environment.

[4]  D. V. Griffiths,et al.  Another look at the stability of slopes with linearly increasing undrained strength , 2015 .

[5]  Alper Turan,et al.  Numerical investigation of spatial aspects of soil structure interaction for secant pile wall circular shafts , 2015 .

[6]  Stefano Marelli,et al.  Rare Event Estimation Using Polynomial-Chaos Kriging , 2017 .

[7]  Toshiyuki Hagiwara,et al.  Two-dimensional base stability of excavations in soft soils using FEM , 2003 .

[8]  Zhe Luo,et al.  Simplified Approach for Reliability-Based Design against Basal-Heave Failure in Braced Excavations Considering Spatial Effect , 2012 .

[9]  Subha Sankar Chowdhury.  Reliability Analysis of Excavation Induced Basal Heave , 2017, Geotechnical and Geological Engineering.

[10]  Yu-you Yang,et al.  Failure of circular shaft subjected to hydraulic uplift: Field and numerical investigation , 2020 .

[11]  D. Dias,et al.  Discrete Kinematic Mechanism for Nonhomogeneous Slopes and Its Application , 2018, International Journal of Geomechanics.

[12]  Xiangfeng Guo,et al.  A Practical Framework for Probabilistic Analysis of Embankment Dams , 2020 .

[13]  Qiujing Pan,et al.  Probabilistic evaluation of tunnel face stability in spatially random soils using sparse polynomial chaos expansion with global sensitivity analysis , 2017 .

[14]  S. C. Chian,et al.  Seismic bearing capacity of non-uniform soil slopes using discretization-based kinematic analysis considering Rayleigh waves , 2018, Soil Dynamics and Earthquake Engineering.

[15]  Jyant Kumar,et al.  Stability of an unsupported vertical circular excavation in clays under undrained condition , 2010 .

[16]  D. Dias,et al.  Reliability analysis of tunnel lining considering soil spatial variability , 2019, Engineering Structures.

[17]  Pengfei Li,et al.  Axisymmetric Arc Sliding Method of Basal Heave Stability Analysis for Braced Circular Excavations , 2018, Symmetry.

[18]  Daniel Dias,et al.  Dynamic probabilistic analysis of non-homogeneous slopes based on a simplified deterministic model , 2021 .

[19]  S. Keawsawasvong,et al.  Undrained basal stability of braced circular excavations in non-homogeneous clays with linear increase of strength with depth , 2019, Computers and Geotechnics.

[20]  Ilya M. Sobol,et al.  Sensitivity Estimates for Nonlinear Mathematical Models , 1993 .

[21]  A. Johari,et al.  Reliability-based analysis of braced excavation in unsaturated soils considering conditional spatial variability , 2019, Computers and Geotechnics.

[22]  K. S. Wong,et al.  Deterministic and reliability analysis of basal heave stability for excavation in spatial variable soils , 2019, Computers and Geotechnics.

[23]  Stefano Marelli,et al.  UQLab: A Framework for Uncertainty Quantification in Matlab , 2014 .

[24]  Sang Seom Jeong,et al.  The effect of arching pressure on a vertical circular shaft , 2013 .

[25]  Ming-Fang Chang,et al.  BASAL STABILITY ANALYSIS OF BRACED CUTS IN CLAY. TECHNICAL NOTE , 2000 .

[26]  Jing Ji,et al.  Behavior of Interfaces between Granular Soil and Structure: A State-of-the-art Review , 2015 .

[27]  Fred H. Kulhawy,et al.  Reliability Assessment of Basal-Heave Stability for Braced Excavations in Clay , 2008 .

[28]  O. Eide,et al.  Stability of strutted excavations in clay , 1956 .

[29]  Nicolas Gayton,et al.  AK-MCS: An active learning reliability method combining Kriging and Monte Carlo Simulation , 2011 .

[30]  Tiago Gerheim Souza Dias,et al.  Large diameter shafts for underground infrastructure , 2015 .

[31]  A. Goh.  Basal heave stability of supported circular excavations in clay , 2017 .

[32]  Joe Wiart,et al.  A new surrogate modeling technique combining Kriging and polynomial chaos expansions - Application to uncertainty analysis in computational dosimetry , 2015, J. Comput. Phys..

[33]  Gordon Tung-Chin Kung,et al.  Probabilistic Analysis of Basal Heave in Deep Excavation , 2011 .

[34]  A. Goh,et al.  Deterministic and reliability assessment of basal heave stability for braced excavations with jet grout base slab , 2017 .

[35]  Daniel Dias,et al.  Three-dimensional face stability analysis of shallow tunnels using numerical limit analysis and material point method , 2021 .

[36]  Jyant Kumar,et al.  Stability of Unsupported Vertical Circular Excavations , 2014 .

[37]  Qiujing Pan,et al.  A sequential sparse polynomial chaos expansion using Bayesian regression for geotechnical reliability estimations , 2020, International Journal for Numerical and Analytical Methods in Geomechanics.

[38]  Claudia Cherubini,et al.  Reliability evaluation of shallow foundation bearing capacity on c', Φ' soils , 2000 .

[39]  S. Keawsawasvong,et al.  Stability of unsupported conical excavations in non-homogeneous clays , 2017 .

[40]  D. V. Griffiths,et al.  Probabilistic stability analyses of undrained slopes with linearly increasing mean strength , 2017 .