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Limit equilibrium analysis for rock slope stability using basic Hoek–Brown strength criterion

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Journal of Central South University 2017年第9期24卷 2154-2163页

作者：邓东平赵炼恒李亮 School of Civil Engineering Central South UniversityChangsha 410075China

Hoek–Brown(HB)strength criterion can reflect rock’s inherent failure nature,so it is more suitable for analyzing the stability of rock ***,the traditional limit equilibrium methods are at present only suitable for analyzing the rock slope stability using the linear equivalent Mohr–Coulomb(EMC)strength parameters instead of the nonlinear HB strength ***,a new method derived to analyze directly the rock slope stability using the nonlinear HB strength criterion for arbitrary curve slip surface was described in the limit equilibrium *** current method was established based on certain assumptions concerning the stresses on the slip surface through amending the initial normal stressσ0 obtained without considering the effect of inter-slice forces,and it can satisfy all static equilibrium conditions of the sliding body,so the current method can obtain the reasonable and strict factor of safety(FOS)*** with the results of other methods in some examples,the feasibility of the current method was ***,the parametric analysis shows that the slope angleβhas an important influence on the difference of the results obtained using the nonlinear HB strength criterion and its linear EMC strength ***β≤45°,both of the results are similar,showing the traditional limit equilibrium methods using the linear EMC strength parameters and the current method are all suitable to analyze rock slope stability,but forβ>60°,the differences of both the results are obvious,showing the actual slope stability state can not be reflected in the traditional limit equilibrium methods,and then the current method should be used.

关键词： Hoek-Brown strength criterion linear equivalent Mohr-Coulomb strength parameters slope stability limit equilibrium slip surface factor of safety

Limit equilibrium stability analysis of slopes under external loads

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Journal of Central South University 2016年第9期23卷 2382-2396页

作者： DENG Dong-ping ZHAO Lian-heng LI Liang School of Civil Engineering Central South University Changsha 410075 China

Two calculation modes for the effect of external load on slope stability, i.e., mode I in which the external load is thought to act on slope surface, and mode II in which the external load is thought to act on slip surface along the force action line, were considered. Meanwhile, four basic distribution patterns of external load were used, of which complex external loads could be composed. In analysis process, several limit equilibrium methods, such as Swedish method, simplified Bishop method, simplified Janbu method, Spencer method, Morgenstern-Price(M-P) method, Sarma method, and unbalanced thrust method, were also adopted to contrast their differences in slope stability under the external load. According to parametric analysis, some conclusions can be obtained as follows:(1) The external load, with the large magnitude, small inclination angle, and acting position close to the slope toe,has more positive effect on slope stability;(2) The results calculated using modes I and II of external load are similar, indicating that the calculation mode of external load has little influence on slope stability;(3) If different patterns of external loads are equivalent to each other, their slope stability under these external loads are the same, and if not, the external load leads to the better slope stability,as action position of the resultant force for external load is closer to the lower sliding point of slip surface.

关键词： slope stability calculation mode of external load distribution pattern of external load limit equilibrium slip surface factor of safety (FOS)

Three-dimensional limit variation analysis on the ultimate pullout capacity of the anchor cables based on the Hoek-Brown failure criterion

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Journal of Mountain Science 2024年第3期21卷 1036-1047页

作者： ZUO Shi ZHAO Lianheng HU Shihong College of Civil Engineering Changsha UniversityChangsha 410022China Hunan provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structure Key Laboratory of Heavy-Haul Railway Engineering StructureMinistry of EducationCentral South UniversityChangsha 410075China College of Civil Engineering Central South UniversityChangsha 410075China

Only simplified two-dimensional model and a single failure mode are adopted to calculate the ultimate pullout capacity(UPC)of anchor cables in most previous *** study focuses on a more comprehensive combination failure mode that consists of bond failure of an anchorage body and failure of an anchored rock *** three-dimensional ultimate pullout capacity of the anchor cables is calculated based on the Hoek-Brown failure criterion and variation analysis *** numerical solution for the curvilinear function in fracture plane is obtained based on the finite difference theory,which more accurately reflects the failure state of the anchor cable,as opposed to that being assumed in *** results reveal that relying solely on a single failure mode for UPC calculations has limitations,as changes in parameter values not only directly impact the UPC value but also can alter the failure model and thus the calculation method.

关键词： Anchor cable Ultimate pullout capacity(UPC) Failure model Variation analysis Hoek-Brown failure criterion

Limit equilibrium method(LEM) of slope stability and calculation of comprehensive factor of safety with double strength-reduction technique

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Journal of Mountain Science 2017年第11期14卷 2311-2324页

作者： DENG Dong-ping LI Liang ZHAO Lian-heng School of Civil Engineering Central South University

When the slope is in critical limit equilibrium(LE) state, the strength parameters have different contribution to each other on maintaining slope stability. That is to say that the strength parameters are not simultaneously reduced. Hence, the LE stress method is established to analyze the slope stability by employing the double strengthreduction(DSR) technique in this work. For calculation model of slope stability under the DSR technique, the general nonlinear Mohr–Coulomb(M–C) criterion is used to describe the shear failure of slope. Meanwhile, the average and polar diameter methods via the DSR technique are both adopted to calculate the comprehensive factor of safety(FOS) of slope. To extend the application of the polar diameter method, the original method is improved in the proposed method. After comparison and analysis on some slope examples, the proposed method's feasibility is verified. Thereafter, the stability charts of slope suitable for engineering application are drawn. Moreover, the studies show that:(1) the average method yields similar results as that of the polardiameter method;(2) compared with the traditional uniform strength-reduction(USR) technique, the slope stability obtained using the DSR techniquetends to be more unsafe; and(3) for a slope in the critical LE state, the strength parameter φ, i.e., internal friction angle, has greater contribution on the slope stability than the strength parameters c, i.e., cohesion.

关键词： Slope stability Nonlinear Mohr-Coulomb (M-C) criterion Double strength-reduction(DSR) technique Slope Comprehensive Factor ofSafety (FOS) Stability charts

Combined influence of nonlinearity and dilation on slope stability evaluated by upper-bound limit analysis

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Journal of Central South University 2017年第7期24卷 1602-1611页

作者： TANG Gao-peng ZHAO Lian-heng LI Liang CHEN Jing-yu School of Civil Engineering Central South UniversityChangsha 410075China

The combined influence of nonlinearity and dilation on slope stability was evaluated using the upper-bound limit analysis *** mechanism of slope collapse was analyzed by dividing it into arbitrary discrete soil blocks with the nonlinear Mohr–Coulomb failure criterion and nonassociated flow *** multipoint tangent(multi-tangent) technique was used to analyze the slope stability by linearizing the nonlinear failure criterion.A general expression for the slope safety factor was derived based on the virtual work principle and the strength reduction technique,and the global slope safety factor can be obtained by the optimization method of nonlinear sequential quadratic *** results show better agreement with previous research result when the nonlinear failure criterion reduces to a linear failure criterion or the non-associated flow rule reduces to an associated flow rule,which demonstrates the rationality of the presented *** safety factors calculated by the multi-tangent inclined-slices technique were smaller than those obtained by the traditional single-tangent inclined-slices *** results show that the multi-tangent inclined-slices technique is a safe and effective method of slope stability limit *** combined effect of nonlinearity and dilation on slope stability was analyzed,and the parameter analysis indicates that nonlinearity and dilation have significant influence on the result of slope stability analysis.

关键词： slope stability analysis nonlinear failure criterion non-associated flow rule multipoint tangent technique upper-bound limit analysis theorem

System reliability analysis of seismic pseudo-static stability of rock wedge based on nonlinear Barton–Bandis criterion

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Journal of Central South University 2020年第11期27卷 3450-3463页

作者： ZHAO Lian-heng JIAO Kang-fu LI De-jian ZUO Shi School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Heavy-Haul Railway Engineering Structure(Ministry of Education) Central South UniversityChangsha 410075China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610031China

Based on the nonlinear Barton–Bandis(B–B)failure criterion,this study considers the system reliability of rock wedge stability under the pseudo-static seismic *** failure probability(Pf)of the system is calculated based on the Monte−Carlo method when considering parameter correlation and *** analysis and sensitivity analysis are carried out to explore the influence of parameters on *** relationships among the failure probability,safety factor(Fs),and variation coefficient are explored,and then stability probability curves of the rock wedge under the pseudo-static seismic load are *** results show that the parameter correlation of the B–B failure criterion has a significant influence on the failure probability,but correlation increases system reliability or decreases system reliability affected by other *** the pseudo-static seismic action,sliding on both planes is the main failure mode of wedge *** addition,the parameters with relatively high sensitivity are two angles related to the joint *** the coefficient of variation is consistent,the probability of system failure is a function of the safety factor.

关键词： 3D rock wedge seismic pseudo-static stability nonlinear Barton–Bandis failure criterion system reliability sensitivity analysis stability probability curves

Comparative study of material point method and upper bound limit analysis in slope stability analysis

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transportation Safety and Environment 2020年第1期2卷 44-57页

作者： Lianheng Zhao Nan Qiao Zhigang Zhao Shi Zuo Xiang Wang School of Civil Engineering Central South UniversityChangshaHunan 410075China Key Laboratory of Heavy-haul Railway Engineering Structure Ministry of EducationCentral South UniversityChangshaHunan 410075China china Railway Seventh Group Co. LtdZhengzhouHenan 450016China School of Civil and Environmental Engineering Hong Kong Polytechnic UniversityYukai RoadKowloonHong KongChina

The upper bound limit analysis(UBLA)is one of the key research directions in geotechnical engineering and is widely used in engineering *** assumes that the slip surface with the minimum factor of safety(FSmin)is the critical slip surface,and then applies it to slope stability ***,the hypothesis of UBLA has not been systematically verified,which may be due to the fact that the traditional numerical method is difficult to simulate the large *** this study,in order to systematically verify the assumption of UBLA,material point method(MPM),which is suitable to simulate the large deformation of continuous media,is used to simulate the whole process of the slope failure,including the large-scale transportation and deposition of soil mass after slope *** a series of comparative studies are conducted on the stability of cohesive slopes using UBLA and *** proposed study indicated that the slope angle,internal friction angle and cohesion have a remarkable effect on the slip surface of the cohesive ***,for stable slopes,the calculation results of the two are relatively ***,for unstable slopes,the slider volume determined by the UBLA is much smaller than the slider volume determined by the *** other words,for unstable slopes,the critical slip surface of UBLA is very different from the slip surface when the slope failure occurs,and when the UBLA is applied to the stability analysis of unstable slope,it will lead to extremely unfavorable results.

关键词： slope stability critical slip surface landslide upper bound limit analysis material point method

Effects of axial cyclic loading at constant confining pressures on deformational characteristics of anisotropic argillite

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Journal of Central South University 2013年第3期20卷 799-811页

作者：张久长周苏华方理刚许湘华 Institute of Geotechnical Engineering Hohai University School of Civil Engineering Central South University guizhou provincial department of transportation

Triaxial cyclic loading tests have been performed to assess the influence of plastic deformation on inelastic deformational properties of anisotropic argillite with bedding planes which is regarded as a kind of transversely isotropic *** argillite's anisotropy and inelastic deformational properties,theoretical formulae for calculating oriented elastic parameters were deduced by the unloading curves,which can be better fitted for the description of its elasticity than loading *** results indicate that with the growth of accumulated plastic,strain,the apparent elastic modulus of argillite decreases in a form of exponential decay function,whereas the apparent Poisson ratio increase in a form of power equation.A ratio of unloading recoverable strain to the total strain increment occurred during a loading cycle is defined to illustrate the characteristic relations between anisotropic coupled elasto-plastic deformation and plastic *** is significant to observe that high stress level and plastic history have an inhibiting effect on argillite anisotropy.

关键词： anisotropic argillite coupled elasto-plasticity cyclic loading tests elastic parameters plastic strain

Upper bound analysis of ultimate pullout capacity of shallow 3-D circular plate anchors based on nonlinear Mohr-Coulomb failure criterion

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Journal of Central South University 2018年第9期25卷 2272-2288页

作者： ZHAO Lian-heng TAN Yi-gao HU Shi-hong DENG Dong-ping YANG Xin-ping School of Civil Engineering Central South University Key Laboratory of Heavy-haul Railway Engineering Structure of Ministry of Education Central South University

Based on the nonlinear Mohr-Coulomb failure criterion and the associated flow rules,the three-dimensional(3-D)axisymmetric failure mechanism of shallow horizontal circular plate anchors that are subjected to the ultimate pullout capacity(UPC)is determined.A derivative function of the projection function for projecting the 3-D axisymmetric failure surface on plane is deduced using the variation *** using difference principle,the primitive function of failure surface satisfying boundary condition and numerical solution to its corresponding ultimate pullout capacity function are *** influences of nonlinear Mohr-Coulomb parameters on UPC and failure mechanism are *** result shows that UPC decreases with dimensionless parameter m and uniaxial tensile strength increases but increases when depth and radius of plate anchor,surface overload,initial cohesion,geomaterial density and friction angle *** failure surface is similar to a symmetrical spatial funnel,and its shape is mainly determined by dimensionless parameter m;the surface damage range expands with the increase of radius and depth of the plate anchor as well as initial cohesion but decreases with the increase of dimensionless parameter m and uniaxial tensile strength as well as geomaterial *** the dimensionless parameter m=2.0,the numerical solution of UPC based on the difference principle is proved to be feasible and effective through the comparison with the exact *** addition,the comparison between solutions of UPC computed by variation method and those computed by upper bound method indicate that variation method outperforms upper bound method.

关键词： shallow circular plate anchors ultimate pullout capacity variation analysis nonlinear Mohr-Coulomb failure criterion upper bound limit analysis