The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hong Zheng - One of the best experts on this subject based on the ideXlab platform.
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modelling the stability of a soil rock mixture slope based on the digital image technology and Strength Reduction numerical manifold method
Engineering Analysis With Boundary Elements, 2021Co-Authors: Yongtao Yang, Hong Zheng, Tao ChenAbstract:Abstract In the present paper, the digital image processing (DIP) technology is employed to establish the structure model of a real SRM (soil-rock-mixture) slope. Based on the structure model, the most recently developed Strength Reduction numerical manifold method (SRNMM) is adopted to investigate the stability of the SRM slope. Based on the proposed numerical model, the testing results show that: 1) the DIP technology can accurately build the structure model of the SRM slope; 2) the SRNMM can obtain the slopes’ FOSs (factors of safety) with satisfactory accuracy, as well as obtain the main failure mode of the slopes; 3) the presence of rock blocks will improve the stability of the soil slopes.
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a stability analysis of rock slopes using a nonlinear Strength Reduction numerical manifold method
Computers and Geotechnics, 2021Co-Authors: Haibin Wang, Hong Zheng, Yongtao Yang, Guanhua SunAbstract:Abstract To investigate rock slope stability, a nonlinear Strength-Reduction numerical manifold method (NSRNMM) using a generalized Hoek-Brown (GHB) criterion is proposed. As it is difficult to implement the nonlinear Strength Reduction method (NSRM) with the use of the GHB criterion by directly reducing the GHB parameters, two equivalent Mohr-Coulomb (MC) criteria, namely, the instantaneous and average equivalent MC criteria that are derived from the GHB criterion, are adopted in the NSRNMM. The implementation details of the NSRNMM are discussed. The stability of two rock slopes, namely, a rock slope with a GHB material and a rock slope with a GHB material and two MC materials, is investigated using the NSRNMM. The numerical results indicate that 1) the proposed NSRNMM using the instantaneous equivalent MC criterion can accurately calculate the safety factor (Fs) of rock slopes and that 2) the Fs predicted with the NSRNMM using the average equivalent MC criterion is more conservative than that using the instantaneous equivalent MC criterion.
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slope stability analysis using convergent Strength Reduction method
Engineering Analysis With Boundary Elements, 2019Co-Authors: Zhibao Nie, Zhihong Zhang, Hong ZhengAbstract:Abstract The Strength Reduction method (SRM) is becoming more and more popular in the stability analysis of slopes. Nevertheless, the criterion for slope failure associated with SRM is controversial, and divergence exists while approaching to the limit equilibrium state of slopes. In this study, the slip body is discretized with constant boundary elements. Since at least one element on the slip surface, referred to as the critical element, should keep still till the slope reaches the limit equilibrium state, the critical element is forced to be fixed throughout while other elements on the slip surface are specified to be contact elements during the Strength Reduction. In this way, convergence is always assured in the open-close iteration of contact between the slip body and the slip bed, no matter how much the Strength of the slip surface is reduced. The limit equilibrium state is defined to be the moment at which the Strength redundancy of the critical element vanishes. The method of bisection is applied to find out the factor of safety (FOS). The proposed method is applied to those benchmark examples and the comparison is made with the limit equilibrium methods (LEM).
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a practical procedure for searching critical slip surfaces of slopes based on the Strength Reduction technique
Computers and Geotechnics, 2009Co-Authors: Hong Zheng, Guanhua Sun, Defu LiuAbstract:Abstract Once an earth slope is led to the limit equilibrium state by means of the finite element–Strength Reduction technique, a plastic zone will go through the slope from the toe to the top. Based on the observation that the critical slip surface will be within the plastic zone and be composed of the points at which the equivalent plastic strain arrives at the maximum in the vertical direction. First, some vertical lines are arranged along the horizontal direction. Then, along each of the vertical lines the point with the maximum equivalent plastic strain is found out. All such points take on a shape of wave and form the functional data. Finally, the functional data are smoothed by the least squares and the position of the critical slip surface is determined. The proposed procedure is verified through comparison with other procedures.
Ping Cao - One of the best experts on this subject based on the ideXlab platform.
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modeling the progressive failure of jointed rock slope using fracture mechanics and the Strength Reduction method
Rock Mechanics and Rock Engineering, 2015Co-Authors: Ping Cao, Ke Zhang, Jingjing Meng, Wenchen FanAbstract:The fracturing process during the progressive failure of a jointed rock slope is numerically investigated by using fracture mechanics and the Strength Reduction method (SRM). A displacement discontinuity method containing frictional elements is developed for the calculation of the stress intensity factor (SIF). The failure initiation of the jointed rock slope is analyzed by evaluating the SIF. A new joint model is proposed by combining solid elements with interface elements in the commercial software FLAC3D. These represent the discontinuous planes in a rock mass on which sliding or separation can occur. The progressive failure process is simulated by reducing the shear Strength of the rock mass, which includes the process of stress concentration, crack initiation, crack propagation, slip weakening, and coalescence of failure surfaces. The factor of safety (FS) and location of the critical failure surface are determined by the SRM. The influence of the joint inclination is investigated using the FS and the SIF. Laboratory experiments on specimens containing an inclined flaw under compression-shear stress are also conducted to investigate the effect of the angle between the shear direction and the flaw inclination, which provides an experimental explanation for the shear behavior of jointed rock. The results show that the joint inclination dominates the failure behavior of jointed rock slope, and two failure patterns have been classified.
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stability of soil nailed slope using Strength Reduction method
European Journal of Environmental and Civil Engineering, 2013Co-Authors: Hang Lin, Wei Xiong, Ping CaoAbstract:This paper describes the influence of soil nail reinforcement on the stability of slopes through a numerical analysis that uses the Strength Reduction method. The stability of nailed slopes is evaluated in terms of factor of safety and potential slip surface. In this paper, the dual-spring structure element in the commercial package (FLAC3D) based on an explicit finite difference formulation is adopted to simulate the characteristics of the nails. A 3D slope model is built to simulate the excavations of the slope and the reinforcement of soil nails. The effects of nail length, orientation, installation location and horizontal spacing on the factor of safety and potential slip surface of the slope, as well as on the nails’ mechanical responses, are numerically investigated.
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progressive failure analysis of slope with strain softening behaviour based on Strength Reduction method
Journal of Zhejiang University Science, 2013Co-Authors: Ke Zhang, Ping Cao, Rui BaoAbstract:Based on the Strength Reduction method and strain-softening model, a method for progressive failure analysis of strain-softening slopes was presented in this paper. The mutation is more pronounced in strain-softening analysis, and the mutation of displacement at slope crest was taken as critical failure criterion. An engineering example was provided to demonstrate the validity of the present method. This method was applied to a cut slope in an industry site. The results are as follows: (1) The factor of safety and the critical slip surface obtained by the present method are between those by peak and residual Strength. The analysis with peak Strength would lead to non-conservative results, but that with residual Strength tends to be overly conservative. (2) The thickness of the shear zone considering strain-softening behaviour is narrower than that with non-softening analysis. (3) The failure of slope is the process of the initiation, propagation and connection of potential failure surface. The Strength parameters are mobilized to a non-uniform degree while progressive failure occurs in the slope. (4) The factor of safety increases with the increase of residual shear strain threshold and elastic modulus. The failure mode of slope changes from shallow slip to deep slip. Poisson’s ratio and dilation angle have little effect on the results.
Yongtao Yang - One of the best experts on this subject based on the ideXlab platform.
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modelling the stability of a soil rock mixture slope based on the digital image technology and Strength Reduction numerical manifold method
Engineering Analysis With Boundary Elements, 2021Co-Authors: Yongtao Yang, Hong Zheng, Tao ChenAbstract:Abstract In the present paper, the digital image processing (DIP) technology is employed to establish the structure model of a real SRM (soil-rock-mixture) slope. Based on the structure model, the most recently developed Strength Reduction numerical manifold method (SRNMM) is adopted to investigate the stability of the SRM slope. Based on the proposed numerical model, the testing results show that: 1) the DIP technology can accurately build the structure model of the SRM slope; 2) the SRNMM can obtain the slopes’ FOSs (factors of safety) with satisfactory accuracy, as well as obtain the main failure mode of the slopes; 3) the presence of rock blocks will improve the stability of the soil slopes.
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a stability analysis of rock slopes using a nonlinear Strength Reduction numerical manifold method
Computers and Geotechnics, 2021Co-Authors: Haibin Wang, Hong Zheng, Yongtao Yang, Guanhua SunAbstract:Abstract To investigate rock slope stability, a nonlinear Strength-Reduction numerical manifold method (NSRNMM) using a generalized Hoek-Brown (GHB) criterion is proposed. As it is difficult to implement the nonlinear Strength Reduction method (NSRM) with the use of the GHB criterion by directly reducing the GHB parameters, two equivalent Mohr-Coulomb (MC) criteria, namely, the instantaneous and average equivalent MC criteria that are derived from the GHB criterion, are adopted in the NSRNMM. The implementation details of the NSRNMM are discussed. The stability of two rock slopes, namely, a rock slope with a GHB material and a rock slope with a GHB material and two MC materials, is investigated using the NSRNMM. The numerical results indicate that 1) the proposed NSRNMM using the instantaneous equivalent MC criterion can accurately calculate the safety factor (Fs) of rock slopes and that 2) the Fs predicted with the NSRNMM using the average equivalent MC criterion is more conservative than that using the instantaneous equivalent MC criterion.
Michael Sloan - One of the best experts on this subject based on the ideXlab platform.
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a case study of multi seam coal mine entry stability analysis with Strength Reduction method
International journal of mining science and technology, 2016Co-Authors: Ihsan Berk Tulu, Gabriel S Esterhuizen, Ted Klemetti, Michael M Murphy, James Sumner, Michael SloanAbstract:In this paper, the advantage of using numerical models with the Strength Reduction method (SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated. A coal mine under variable topography from the Central Appalachian region is used as a case study. At this mine, unexpected roof conditions were encountered during development below previously mined panels. Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels. Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries. The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations. The SRM-calculated stability factors were compared with observations made during the site visits, and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case. It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.
Ke Zhang - One of the best experts on this subject based on the ideXlab platform.
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modeling the progressive failure of jointed rock slope using fracture mechanics and the Strength Reduction method
Rock Mechanics and Rock Engineering, 2015Co-Authors: Ping Cao, Ke Zhang, Jingjing Meng, Wenchen FanAbstract:The fracturing process during the progressive failure of a jointed rock slope is numerically investigated by using fracture mechanics and the Strength Reduction method (SRM). A displacement discontinuity method containing frictional elements is developed for the calculation of the stress intensity factor (SIF). The failure initiation of the jointed rock slope is analyzed by evaluating the SIF. A new joint model is proposed by combining solid elements with interface elements in the commercial software FLAC3D. These represent the discontinuous planes in a rock mass on which sliding or separation can occur. The progressive failure process is simulated by reducing the shear Strength of the rock mass, which includes the process of stress concentration, crack initiation, crack propagation, slip weakening, and coalescence of failure surfaces. The factor of safety (FS) and location of the critical failure surface are determined by the SRM. The influence of the joint inclination is investigated using the FS and the SIF. Laboratory experiments on specimens containing an inclined flaw under compression-shear stress are also conducted to investigate the effect of the angle between the shear direction and the flaw inclination, which provides an experimental explanation for the shear behavior of jointed rock. The results show that the joint inclination dominates the failure behavior of jointed rock slope, and two failure patterns have been classified.
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progressive failure analysis of slope with strain softening behaviour based on Strength Reduction method
Journal of Zhejiang University Science, 2013Co-Authors: Ke Zhang, Ping Cao, Rui BaoAbstract:Based on the Strength Reduction method and strain-softening model, a method for progressive failure analysis of strain-softening slopes was presented in this paper. The mutation is more pronounced in strain-softening analysis, and the mutation of displacement at slope crest was taken as critical failure criterion. An engineering example was provided to demonstrate the validity of the present method. This method was applied to a cut slope in an industry site. The results are as follows: (1) The factor of safety and the critical slip surface obtained by the present method are between those by peak and residual Strength. The analysis with peak Strength would lead to non-conservative results, but that with residual Strength tends to be overly conservative. (2) The thickness of the shear zone considering strain-softening behaviour is narrower than that with non-softening analysis. (3) The failure of slope is the process of the initiation, propagation and connection of potential failure surface. The Strength parameters are mobilized to a non-uniform degree while progressive failure occurs in the slope. (4) The factor of safety increases with the increase of residual shear strain threshold and elastic modulus. The failure mode of slope changes from shallow slip to deep slip. Poisson’s ratio and dilation angle have little effect on the results.
