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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

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)

Limit equilibrium analysis for stability of soil nailed slope and optimum design of soil nailing parameters

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Journal of Central South University 2017年第11期24卷 2496-2503页

作者： DENG Dong-ping LI liang zhao lian-heng School of Civil Engineering Central South UniversityChangsha 410075China

Reinforcement of slopes using soil nailing can effectively improve slope stability, and it has been widely used in upgrading cut slopes. Based on the assumptions of stresses on the slip surface, a new method for analyzing the stability of a slope reinforced with soil nails was established in the limit equilibrium theory framework, by considering that slope sliding occurs owing to shear failure of the slip surface, which subjects to Mohr–Coulomb(M–C) strength criterion. Meanwhile, in order to easily analyze the stability of a soil nailed slope in actual engineering and facilitate optimum design of parameters for soil nailing, factor of safety(FOS) contour curve charts were drawn on the basis of the established linear proportional relationship between the spacing of soil nails and slope height, and the length of soil nails and slope height. Then, by analyzing and verifying the results obtained from classic examples, some conclusions can be got as follows: 1) The results obtained from the current method are close to those obtained from the traditional limit equilibrium methods, and the current method can provide a strict solution for the slope FOS as it satisfies all the static equilibrium conditions of a sliding body, thus confirming the feasibility of the current method; 2) The slope FOS contour curve charts can be used not only to reliably analyze the stability of a soil nailed slope, but also to design optimally the parameters of soil nailing for the slope with a certain safety requirement.

关键词： slope stability soil nailing limit equilibrium factor of safety contour curve optimum design

Influence of non-dimensional strength parameters on the seismic stability of cracked slopes

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Journal of Mountain Science 2019年第1期16卷 153-167页

作者： zhao lian-heng Cheng Xiao LI De-jian ZHANG Ying-bin School of Civil Engineering Central South University Key Laboratory of Heavy-haul Railway Engineering Structure Ministry of Education Central South University Key Laboratory of Transportation Tunnel Engineering Ministry of Education Southwest Jiaotong University Department of Geotechnical Engineering School of Civil Engineering Southwest Jiaotong University

Cracks in rock or soil slopes influence the stability and durability of the slopes. Seismic forces can trigger slope disasters, particularly in the cracked slopes. Considering the nonlinear characteristics of materials, the more generalized nonlinear failure criterion proposed by Baker is adopted. The influence of non-dimensional strength parameters on the stability of cracked slopes under earthquakes is performed using the upper bound limit analysis. The seismic displacement is calculated by adopting the logarithmic spiral failure surface according to the sliding rigid block model. Based on the existing studies, two methods for the stability analysis of cracked slopes under earthquakes are introduced: the pseudo-static method(with the factor of safety(Fs) as an evaluation index), and the displacement-based method(with the seismic displacement as an evaluation index). The pseudo-static method can only determine the instantaneous stability state of the cracked slope, yet the displacement-based methodreflects the stability variation of cracked slopes during earthquakes. The results indicate that the nondimensional strength parameters affect the factor of safety and seismic displacement of slopes significantly. The non-dimensional strength parameter(n) controlling the curvature of strength function shapes on the slope stability is affected by other parameters. Owing to cracks, the effect of non-dimensional strength parameters on seismic displacement becomes more significant.

关键词： Cracked slopes Upper bound limit analysis(UBLA) Generalized nonlinear failure criterion Pseudo-static method Displacement-based method

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

Seismic dynamic stability of double-slider rock slopes containing tension cracks

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Journal of Mountain Science 2023年第7期20卷 2093-2106页

作者： ZHU Chen-hao zhao lian-heng HU Shi-hong ZUO Shi YU Cheng-hao School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Heavy-haul Railway Engineering Structure Ministry of EducationCentral South UniversityChangsha 410075China

Earthquakes have significant impact on rock slopes,thus studying the seismic stability of double-slider rock slopes containing tension cracks is *** proposed an analysis method on the seismic dynamic slope *** method utilizes discrete Fourier transform to decompose real earthquake waves into a combination of harmonic *** waves are then used in conjunction with the pseudo-dynamic method and safety factor calculation formula to compute the safety *** approach accurately captures the influence of seismic time history characteristics on the dynamic stability of double-slider rock slopes containing tension *** minimum safety factor in the obtained time history curves of the safety factor reflects the most unfavorable state of the slopes under seismic *** analysis is conducted using six sets of actual earthquake ground motion data obtained from the Pacific Earthquake Engineering Research Center’s NGAWest2 ground-shaking record *** conclusions are as follows:(1)There is an inverse correlation between the average seismic acceleration amplitude and the minimum safety ***,the seismic acceleration amplitude standard deviation shows a positive correlation with the minimum safety *** global sensitivity of geometric parameters in the slope model is higher than other influencing factors.(2)The proposed dynamic stability analysis method can capture the dynamic characteristics of earthquakes,emphasizing the minimum safety factor of the slope in the seismic time history as a stability *** contrast,the pseudo-static method may yield unsafe results.(3)A safety factor expression considering hydrostatic pressure is proposed.A negative correlation was observed between the height of the water level line and the minimum safety factor.

关键词： Earthquake Rock slope Tension crack Modified Pseudo-Dynamic Method Discrete Fourier transform

Sensitivity analysis of regional rainfall-induced landslide based on UAV photogrammetry and LSTM neural network

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Journal of Mountain Science 2023年第11期20卷 3312-3326页

作者： zhao lian-heng XU Xin LYU Guo-shun HUANG Dong-liang LIU Min CHEN Qi-min School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Heavy-haul Railway Engineering Structure Ministry of EducationCentral South UniversityChangsha410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures CentralSouth UniversityChangsha 410075China Hunan Tieyuan Civil Engineering Testing Co. LTDChangsha 410075China

Rainfall stands out as a critical trigger for landslides,particularly given the intense summer rainfall experienced in Zheduotang,a transitional zone from the southwest edge of Sichuan Basin to Qinghai Tibet *** area is characterized by adverse geological conditions such as rock piles,debris slopes and unstable ***,due to the absence of historical rainfall records and landslide inventories,empirical methods are not applicable for the analysis of rainfall-induced *** we employ a physically based landslide susceptibility analysis model by using highprecision unmanned aerial vehicle(UAV)photogrammetry,field boreholes and long short term memory(LSTM)neural network to obtain regional topography,soil properties,and rainfall *** applied the Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability(TRIGRS)model to simulate the distribution of shallow landslides and variations in porewater pressure across the region under different rainfall intensities and three rainfall patterns(advanced,uniform,and delayed).The landslides caused by advanced rainfall pattern mostly occurred in the first 12 hours,but the landslides caused by delayed rainfall pattern mostly occurred in the last 12 ***,all the three rainfall patterns yielded landslide susceptibility zones categorized as high(1.16%),medium(8.06%),and low(90.78%).Furthermore,total precipitation with a rainfall intensity of 35 mm/h for 1 hour was less than that with a rainfall intensity of 1.775 mm/h for 24hours,but the areas with high and medium susceptibility increased by 3.1%.This study combines UAV photogrammetry and LSTM neural networks to obtain more accurate input data for the TRIGRS model,offering an effective approach for predicting rainfall-induced shallow landslides in regions lacking historical rainfall records and landslide inventories.

关键词： Regional landslide TRIGRS UAV photography Rainfall landslide LSTM neural network

Limit equilibrium method for slope stability based on assumed stress on slip surface

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Journal of Central South University 2016年第11期23卷 2972-2983页

作者：邓东平赵炼恒李亮 School of Civil Engineering Central South University

In the limit equilibrium framework, two- and three-dimensional slope stabilities can be solved according to the overall force and moment equilibrium conditions of a sliding body. In this work, based on Mohr-Coulomb(M-C) strength criterion and the initial normal stress without considering the inter-slice(or inter-column) forces, the normal and shear stresses on the slip surface are assumed using some dimensionless variables, and these variables have the same numbers with the force and moment equilibrium equations of a sliding body to establish easily the linear equation groups for solving them. After these variables are determined, the normal stresses, shear stresses, and slope safety factor are also obtained using the stresses assumptions and M-C strength criterion. In the case of a three-dimensional slope stability analysis, three calculation methods, namely, a non-strict method, quasi-strict method, and strict method, can be obtained by satisfying different force and moment equilibrium conditions. Results of the comparison in the classic two- and three-dimensional slope examples show that the slope safety factors calculated using the current method and the other limit equilibrium methods are approximately equal to each other, indicating the feasibility of the current method; further, the following conclusions are obtained: 1) The current method better amends the initial normal and shear stresses acting on the slip surface, and has the identical results with using simplified Bishop method, Spencer method, and Morgenstern-Price(M-P) method; however, the stress curve of the current method is smoother than that obtained using the three abovementioned methods. 2) The current method is suitable for analyzing the two- and three-dimensional slope stability. 3) In the three-dimensional asymmetric sliding body, the non-strict method yields safer solutions, and the results of the quasi-strict method are relatively reasonable and close to those of the strict method, indicatin

关键词： two-dimensional slope three-dimensional slope limit equilibrium analysis normal stress shear stress safety factor

Assessing the range of blasting-induced cracks in the surrounding rock of deeply buried tunnels based on the unified strength theory

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Journal of Central South University 2024年第7期31卷 2341-2364页

作者： LI liang CHEN Jia-jun zhao lian-heng HE Ke-pei HU Shi-hong LI Hua-long School of Civil Engineering Central South UniversityChangsha 410075China Key Laboratory of Heavy-haul Railway Engineering Structure Ministry of EducationCentral South UniversityChangsha 410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structure Central South UniversityChangsha 410075China

Blasting-induced cracks in the rock surrounding deeply buried tunnels can result in water gushing and rock mass collapse,posing significant safety ***,previous theoretical studies on the range of blasting-induced cracks often ignore the impact of the in-situ stress,especially that of the intermediate principal *** particle displacement−crack radius relationship was established in this paper by utilizing the blasthole cavity expansion equation,and theoretical analytical formulas of the stress−displacement relationship and the crack radius were derived with unified strength theory to accurately assess the range of cracks in deep surrounding rock under a blasting *** analysis showed that the crushing zone size was positively correlated with in-situ stress,intermediate principal stress,and detonation pressure,whereas negatively correlated with Poisson ratio and decoupling *** dilatancy angle-crushing zone size relationship exhibited nonmonotonic *** relationships in the crushing zone and the fracture zone exhibited opposite trends under the influence of only in-situ stress or intermediate principal *** the in-situ stress increased from 0 to 70 MPa,the rate of change in the crack range and the attenuation rate of the peak vibration velocity gradually slowed.

关键词： deep drilling and blasting cracks in surrounding rock unified strength theory intermediate principle stress in-situ stress cavity expansion dilatancy characteristics

Water inflow forecasting for tunnel considering nonlinear variation of permeability coefficient

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Journal of Central South University 2017年第7期24卷 1612-1618页

作者： Cheng Pan zhao lian-heng ZHANG Shao-wei LI liang SHEN Zhi-qiang NING Peng-fei ZHANG Ze-hai Department of Civil Engineering College of Basic EducationNational University of Defense Technology School of Civil Engineering Central South University

To assess the water inflow which is more suitable to the actual conditions of tunnel,an empirical correlation about the permeability coefficient changing with depth is *** that the surrounding rock is heterogeneous isotropy,the formula for calculating water inflow of tunnel with the nonlinear variation of permeability coefficient is *** the contrast analysis with the existing formulas,the presented method has the similar value to them;moreover,the presented method has more simple form and easy to *** to parameter analysis,the water inflow decreases after considering the nonlinear variation of permeability *** the attenuation coefficient a>0,the water inflow increases first till reaches the maximum at a certain depth,then decreases and is close to 0 finally if deep ***,it is better to keep away from the certain depth where it is with the maximum water inflow for safe operation and economical construction,and reduce the water *** on the analysis,the radius of tunnel has less impact on the amount of water inflow,and the water inflow just increases by 6.7% when the radius of tunnel increases by 1 m.

关键词： water inflow forecasting heterogeneous isotropy of surrounding rock permeability coefficient tunnel