The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Xiaoli Yang - One of the best experts on this subject based on the ideXlab platform.
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Cavity expansion analysis with non-linear Failure Criterion
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 2011Co-Authors: Xiaoli Yang, Jin-feng ZouAbstract:The conventional calculation of an expanding cavity is formulated in terms of a linear Failure Criterion. However, experiments show that Failure criteria are non-linear for most geomaterials. This paper investigates the cavity expansion problem in an isotropic and homogeneous medium using a non-linear Failure Criterion. A procedure for analysing the expansion of cylindrical and spherical cavities is described, with effects of dilatancy considered. The solutions for stress and displacement around the cavity are presented in the elastic and plastic zones. A study is carried out to illustrate the effects of various parameters on the behaviour of the expanding cavity.
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Upper Bound Solutions for the Face Stability of Shallow Circular Tunnels Subjected to Nonlinear Failure Criterion
Deep and Underground Excavations, 2010Co-Authors: Fu Huang, Xiaoli YangAbstract:Based on the previous Failure mechanism, the face stability of shallow circular tunnels is investigated using the upper bound theorem of limit analysis in conjunction with the nonlinear Failure Criterion. By using generalized tangential technique, the nonlinear Failure Criterion is introduced to optimize the retaining pressure of tunnel face. The optimum value of retaining pressure of tunnel face is obtained by employing nonlinear programming which is characterized by two variables with constraint. In order to evaluate the validity of the numerical results, the optimum solutions of this paper are compared with the value of retaining pressure calculated by linear Failure Criterion. The agreements indicate the proposed method is effective. The numerical results show that the nonlinear Failure Criterion has an important influence on the retaining pressure of tunnel face.
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estimation of seismic passive earth pressures with nonlinear Failure Criterion
Engineering Structures, 2006Co-Authors: Xiaoli YangAbstract:Abstract Most conventional calculation of seismic passive earth pressures is based on a linear Mohr–Coulomb Failure Criterion. However, a substantial amount of experimental data shows that almost all geomaterials follow a nonlinear Failure Criterion in practice. In this paper, the influence of a nonlinear strength envelope is considered in the framework of limit analysis of plasticity. The seismic passive earth pressures on the rigid walls in seismic conditions are estimated using the upper bound theorem of limit analysis in conjunction with the nonlinear Failure Criterion. A generalized tangential technique, one tangential line to the nonlinear Failure Criterion, is used to develop the external work and internal energy dissipation. The seismic earth passive pressure is obtained from optimization. An extended Rankine’s theory is proposed with the same nonlinear Failure Criterion. In order to evaluate the validity of the numerical results using the generalized tangential technique, the solutions of seismic passive earth pressure are also presented in the framework of the extended Rankine’s theory. Numerical results for different seismic coefficients and various nonlinear parameters of the Failure Criterion are compared with each other. The upper bound solutions using the generalized tangential technique are almost equal to the extended Rankine’s theoretical solutions, with the maximum difference being less than 1%. The good agreement shows that the generalized tangential technique is an effective method for evaluating the seismic passive earth pressure with a nonlinear Failure Criterion. This paper extends the work of the seismic passive earth pressure using a linear Mohr–Coulomb Failure Criterion in previous literature to that using the nonlinear Failure Criterion.
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upper bound solution for ultimate bearing capacity with a modified hoek brown Failure Criterion
International Journal of Rock Mechanics and Mining Sciences, 2005Co-Authors: Xiaoli Yang, Jianhua YinAbstract:Abstract Conventional calculations of ultimate bearing capacity are formulated in terms of a linear Mohr–Coulomb (MC) Failure Criterion. However, experimental data shows that the strength envelops of almost all types of rocks are nonlinear over the wide range of normal stresses. In this paper, the strength envelope of rock masses is considered to follow a modified Hoek–Brown Failure Criterion that is a nonlinear Failure Criterion. Two different kinds of techniques are used to develop the ultimate bearing capacity in the framework of limit analysis in plasticity. The first technique is the generalized tangential technique proposed by the authors. Based on a multi-wedge translation Failure mechanism, a generalized tangential technique is used to formulate the bearing capacity problem as a classical optimization problem where the objective function, which is to be minimized with respects to the parameters of Failure mechanism and the location of tangency point, corresponds to the dissipated power. The minimum solution is obtained by optimization. Using the technique, the effects of rock weight under the base of the footing and surcharge load can be considered. The second technique, “tangential” line technique, was originally used to analyze slope stability with a nonlinear Failure Criterion. In order to assess the validity of the proposed method, the “tangential” line technique is extended to evaluate the bearing capacity factor with the nonlinear Failure Criterion, where the effects of self-weight and surcharge load on the bearing capacity cannot considered. The second technique, however, has to utilize the previously calculated ultimate bearing capacity factor with a linear MC Failure Criterion. Numerical results are compared and presented for practical use in rock engineering.
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Upper bound solution for ultimate bearing capacity with a modified Hoek–Brown Failure Criterion
International Journal of Rock Mechanics and Mining Sciences, 2005Co-Authors: Xiaoli Yang, Jianhua YinAbstract:Conventional calculations of ultimate bearing capacity are formulated in terms of a linear Mohr-Coulomb (MC) Failure Criterion. However, experimental data shows that the strength envelops of almost all types of rocks are nonlinear over the wide range of normal stresses. In this paper, the strength envelope of rock masses is considered to follow a modified Hoek-Brown Failure Criterion that is a nonlinear Failure Criterion. Two different kinds of techniques are used to develop the ultimate bearing capacity in the framework of limit analysis in plasticity. The first technique is the generalized tangential technique proposed by the authors. Based on a multi-wedge translation Failure mechanism, a generalized tangential technique is used to formulate the bearing capacity problem as a classical optimization problem where the objective function, which is to be minimized with respects to the parameters of Failure mechanism and the location of tangency point, corresponds to the dissipated power. The minimum solution is obtained by optimization. Using the technique, the effects of rock weight under the base of the footing and surcharge load can be considered. The second technique, "tangential" line technique, was originally used to analyze slope stability with a nonlinear Failure Criterion. In order to assess the validity of the proposed method, the "tangential" line technique is extended to evaluate the bearing capacity factor with the nonlinear Failure Criterion, where the effects of self-weight and surcharge load on the bearing capacity cannot considered. The second technique, however, has to utilize the previously calculated ultimate bearing capacity factor with a linear MC Failure Criterion. Numerical results are compared and presented for practical use in rock engineering.Department of Civil and Environmental Engineerin
Seyed Rahman Torabi - One of the best experts on this subject based on the ideXlab platform.
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A modified Failure Criterion for transversely isotropic rocks
Geoscience Frontiers, 2014Co-Authors: Omid Saeidi, Vamegh Rasouli, Rashid Geranmayeh Vaneghi, Raoof Gholami, Seyed Rahman TorabiAbstract:A modified Failure Criterion is proposed to determine the strength of transversely isotropic rocks. Mechanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consideration. Afterward, introduced triaxial rock strength Criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy indexes in literature showed reasonable results for the studied rock samples. The modified Criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified Failure Criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.
Jianhua Yin - One of the best experts on this subject based on the ideXlab platform.
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upper bound solution for ultimate bearing capacity with a modified hoek brown Failure Criterion
International Journal of Rock Mechanics and Mining Sciences, 2005Co-Authors: Xiaoli Yang, Jianhua YinAbstract:Abstract Conventional calculations of ultimate bearing capacity are formulated in terms of a linear Mohr–Coulomb (MC) Failure Criterion. However, experimental data shows that the strength envelops of almost all types of rocks are nonlinear over the wide range of normal stresses. In this paper, the strength envelope of rock masses is considered to follow a modified Hoek–Brown Failure Criterion that is a nonlinear Failure Criterion. Two different kinds of techniques are used to develop the ultimate bearing capacity in the framework of limit analysis in plasticity. The first technique is the generalized tangential technique proposed by the authors. Based on a multi-wedge translation Failure mechanism, a generalized tangential technique is used to formulate the bearing capacity problem as a classical optimization problem where the objective function, which is to be minimized with respects to the parameters of Failure mechanism and the location of tangency point, corresponds to the dissipated power. The minimum solution is obtained by optimization. Using the technique, the effects of rock weight under the base of the footing and surcharge load can be considered. The second technique, “tangential” line technique, was originally used to analyze slope stability with a nonlinear Failure Criterion. In order to assess the validity of the proposed method, the “tangential” line technique is extended to evaluate the bearing capacity factor with the nonlinear Failure Criterion, where the effects of self-weight and surcharge load on the bearing capacity cannot considered. The second technique, however, has to utilize the previously calculated ultimate bearing capacity factor with a linear MC Failure Criterion. Numerical results are compared and presented for practical use in rock engineering.
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Upper bound solution for ultimate bearing capacity with a modified Hoek–Brown Failure Criterion
International Journal of Rock Mechanics and Mining Sciences, 2005Co-Authors: Xiaoli Yang, Jianhua YinAbstract:Conventional calculations of ultimate bearing capacity are formulated in terms of a linear Mohr-Coulomb (MC) Failure Criterion. However, experimental data shows that the strength envelops of almost all types of rocks are nonlinear over the wide range of normal stresses. In this paper, the strength envelope of rock masses is considered to follow a modified Hoek-Brown Failure Criterion that is a nonlinear Failure Criterion. Two different kinds of techniques are used to develop the ultimate bearing capacity in the framework of limit analysis in plasticity. The first technique is the generalized tangential technique proposed by the authors. Based on a multi-wedge translation Failure mechanism, a generalized tangential technique is used to formulate the bearing capacity problem as a classical optimization problem where the objective function, which is to be minimized with respects to the parameters of Failure mechanism and the location of tangency point, corresponds to the dissipated power. The minimum solution is obtained by optimization. Using the technique, the effects of rock weight under the base of the footing and surcharge load can be considered. The second technique, "tangential" line technique, was originally used to analyze slope stability with a nonlinear Failure Criterion. In order to assess the validity of the proposed method, the "tangential" line technique is extended to evaluate the bearing capacity factor with the nonlinear Failure Criterion, where the effects of self-weight and surcharge load on the bearing capacity cannot considered. The second technique, however, has to utilize the previously calculated ultimate bearing capacity factor with a linear MC Failure Criterion. Numerical results are compared and presented for practical use in rock engineering.Department of Civil and Environmental Engineerin
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stability analysis of rock slopes with a modified hoek brown Failure Criterion
International Journal for Numerical and Analytical Methods in Geomechanics, 2004Co-Authors: Xiaoli Yang, Jianhua YinAbstract:The original Hoek–Brown (HB) Failure Criterion was used to analyse the stability of rock slopes. For highly fractured rock, the original HB Failure Criterion has been modified, but its effect on the stability of rock slopes has not been studied. Within the framework of the kinematical approach of limit analysis, this paper computes the rigorous upper bounds of stability factors of homogeneous rock slopes with the modified HB Failure Criterion under the plane strain condition, by employing a ‘generalized tangential’ technique. In such technique, instead of using the modified HB Failure Criterion, a series of linear Failure surfaces tangent to the actual non-linear Failure surface are utilized to derive the upper bound solutions, incorporating a new parameter n ranging from 0.5 to 0.65. The numerical results are compared with other published solutions for the case of n=0.5. The effects of the n on the stability factors of rock slopes are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
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Stability analysis of rock slopes with a modified Hoek–Brown Failure Criterion
International Journal for Numerical and Analytical Methods in Geomechanics, 2004Co-Authors: Xiaoli Yang, Jianhua YinAbstract:The original Hoek–Brown (HB) Failure Criterion was used to analyse the stability of rock slopes. For highly fractured rock, the original HB Failure Criterion has been modified, but its effect on the stability of rock slopes has not been studied. Within the framework of the kinematical approach of limit analysis, this paper computes the rigorous upper bounds of stability factors of homogeneous rock slopes with the modified HB Failure Criterion under the plane strain condition, by employing a ‘generalized tangential’ technique. In such technique, instead of using the modified HB Failure Criterion, a series of linear Failure surfaces tangent to the actual non-linear Failure surface are utilized to derive the upper bound solutions, incorporating a new parameter n ranging from 0.5 to 0.65. The numerical results are compared with other published solutions for the case of n=0.5. The effects of the n on the stability factors of rock slopes are discussed. Copyright © 2004 John Wiley & Sons, Ltd.
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Slope Stability Analysis with Nonlinear Failure Criterion
Journal of Engineering Mechanics, 2004Co-Authors: Xiaoli Yang, Jianhua YinAbstract:A linear Failure Criterion is widely used in slope stability analyses. However, the strength envelope of almost all geomaterials has the nature of nonlinearity. This paper computes rigorous upper b...
Omid Saeidi - One of the best experts on this subject based on the ideXlab platform.
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A modified Failure Criterion for transversely isotropic rocks
Geoscience Frontiers, 2014Co-Authors: Omid Saeidi, Vamegh Rasouli, Rashid Geranmayeh Vaneghi, Raoof Gholami, Seyed Rahman TorabiAbstract:A modified Failure Criterion is proposed to determine the strength of transversely isotropic rocks. Mechanical properties of some metamorphic and sedimentary rocks including gneiss, slate, marble, schist, shale, sandstone and limestone, which show transversely isotropic behavior, were taken into consideration. Afterward, introduced triaxial rock strength Criterion was modified for transversely isotropic rocks. Through modification process an index was obtained that can be considered as a strength reduction parameter due to rock strength anisotropy. Comparison of the parameter with previous anisotropy indexes in literature showed reasonable results for the studied rock samples. The modified Criterion was compared to modified Hoek-Brown and Ramamurthy criteria for different transversely isotropic rocks. It can be concluded that the modified Failure Criterion proposed in this study can be used for predicting the strength of transversely isotropic rocks.
Kenneth Jaquay - One of the best experts on this subject based on the ideXlab platform.
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A Strain Based Failure Criterion for Stainless Steel 316L
Volume 2: Plant Systems Structures and Components; Safety and Security; Next Generation Systems; Heat Exchangers and Cooling Systems, 2012Co-Authors: Necip Onder Akinci, Kenneth JaquayAbstract:This study presents a proposed Failure Criterion for evaluation of stainless steel 316L plates subjected to multiaxial stresses. Effects of membrane and bending stresses are investigated. The experimental data used in the development of the Failure Criterion is based on 316L forming limit diagram. Strains obtained from the forming limit diagram are used for calculation of stresses and triaxiality factors. The proposed Failure Criterion is compared with those available in the literature. Effects of bending stresses on the ductility of 316L plates are discussed.Copyright © 2012 by ASME
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A Strain Based Failure Criterion for Stainless Steel 316L
Volume 2: Plant Systems Structures and Components; Safety and Security; Next Generation Systems; Heat Exchangers and Cooling Systems, 2012Co-Authors: Necip Onder Akinci, Kenneth JaquayAbstract:This study presents a proposed Failure Criterion for evaluation of stainless steel 316L plates subjected to multiaxial stresses. Effects of membrane and bending stresses are investigated. The experimental data used in the development of the Failure Criterion is based on 316L forming limit diagram. Strains obtained from the forming limit diagram are used for calculation of stresses and triaxiality factors. The proposed Failure Criterion is compared with those available in the literature. Effects of bending stresses on the ductility of 316L plates are discussed.
