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Probabilistic assessment of rock slopes stability using the response surface approach——A case study

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International Journal of Mining Science and Technology 2019年第3期29卷 357-370页

作者： Hassan Basahel Hani Mitri Department of Mining and Material Engineering McGill University

This paper examines the stability condition of a jointed rock slope in the south western region of Saudi Arabia using deterministic and probabilistic approaches,under both dry and wet conditions.The study area is characterized by complex geology in rugged terrains.The stability analysis is carried out using the code FLAC3D to generate a 3-dimensional,ubiquitous joint model,to determine the influence of the dominant,unfavourable discontinuity orientation with respect to the slope face.The deterministic analysis is first implemented using the mean values of the selected random variables,namely the dip,dip direction and friction angle of the dominant discontinuity set,and the stability condition is assessed with a factor of safety based on the classical frictional joint constitutive model.A Box-Behnken design(BBD)approach is then adopted to create the surface response function as a second order polynomial for the factor of safety.To do so,fifteen FLAC3D models are generated in accordance with the BBD.Based on this,10,000 simulations of different slope realizations are carried out using Monte-Carlo simulation technique,and the probability of unsatisfactory of performance of the rock slope is assessed.It is shown that the probabilistic approach provides more insight and confidence in the stability condition of the rock slope,both under dry and steady state heavy rainfall conditions.A discussion is presented on the significance of accepting lower safety factors when heavy rainfall conditions are encountered.

关键词： Rock slope stability Box-Behnken design Probabilistic analysis of slopes Response surface

Effect of buried plates on scour profiles downstream of hydraulic jump in open channels with horizontal and reverse bed slopes

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Water Science and Engineering 2016年第4期9卷 329-335页

作者： Akram Abbaspour Sahar Parvini Ali Hosseinzadeh Dalir Department of Water Engineering University of Tabriz

Local scour downstream of sluice gates in erosive beds is one of the main concerns of hydraulic engineers because it can cause considerable damage to structures.Many researchers have conducted various studies to predict the maximum depth and length of scour holes and to develop new methods to control this phenomenon.In the methods that have recently been examined,embedded buried plates are used to control the scour in the erosive beds.In this study,using a physical model,the effect of buried plates in erosive beds on the depth of scour downstream of a hydraulic jump was studied.Several experiments were performed in which plates were buried at 50° and 90° angles at different distances from the apron in open channels with horizontal and reverse bed slopes.The results of experiments in which the scour profiles were drawn in dimensionless forms show that the angle and position of the plates are important to controlling and reducing scour depth.In fact,by reducing the angle of buried plates,the maximum depth of scour is also reduced.Also,comparison of the results of a single buried plate and double buried plates shows that using two buried plates at the distances of 30 and 45 cm from the non-erodible bed is more effective in reducing the scour depth.The best distances of the buried plates with angles of 90° and 50° from the non-erodible bed are 45 cm and 30 cm,respectively,in the condition with a single buried plate.

关键词： Local scour Buried plates Hydraulic jump Horizontal and reverse bed slopes

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

BACK-ANALYSIS ON THE SHEARING STRENGTH IN SLIP SURFACE UNDER TRANSECTING LAYER FAILURES AND ASSESSMENT OF THE STABILITY FOR ANTIDIP ROCK slopes

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Scientia Geologica Sinica 1998年第2期 66-77页

作者： Yang Zhifa, Shang Yanjun and Yuan Baoyuan Institute of Geology, Chinese Academy of Sciences, Beijing 100029 Wang Jing and Tang Chunhua Middle South Institute for Design of Hydroelectric Projects, MERMWC, Changsha 410014

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关键词： SLIP SURFACE STRENGTH slopes ANTIDIP ROCK AND

Investigation of rockfall-prone road cut slope near Lengpui Airport,Mizoram,India

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第1期11卷 146-158页

作者： A.K.Verma Sahil Sardana Pushpendra Sharma Lal Dinpuia T.N.Singh Department of Mining Engineering Indian Institute of Technology (Banaras Hindu Universiy) Department of Mining Engineering Indian Institute of Technology (Indian School of Mines) Department of Civil Engineering Lassonde School of Engineering York University Department of Ceology Pachhunga University College Department of Earth Sciences Indian Institute of Technology Bombay

Rockfall is one of severe natural hazards that are frequently reported in northeast region of India. It carries rock block falling from the cliff with high velocities and energies which can result in damages to vehicles, disruption to transportation, injuries and fatalities. The massive rockfall event which occurred in April 2017 on the highway NH-44 A, near Lengpui Airport, blocked the traffic for 1 d, and fortunately,no casualties were reported as the event occurred in the night. This is the only highway connecting the Aizawl city to the airport and the region is highly prone to rockfall events. Hence assessment of rockfall along this highway is necessary. In the current study, rockfall hazard assessment has been carried out on three locations by rockfall hazard rating system(RHRS). During pre-failure analysis, the result shows that most hazardous slopes have RHRS score of 639. The slopes were found to be vulnerable and later on the rockfall activity occurred. Three-dimensional(3 D) stability analysis has been carried out using 3 DEC software package to analyze the failure behavior and to decide the rockfall-prone zone(unstable blocks)for slope. The total displacement of 2.24 cm and velocity of 2,25 mm/s of the failed block have been observed in the numerical analysis. Further, the rockfall vulnerable zone(unstable blocks) is considered to determine the parameters such as run-out distance, bounce height and energies of the falling rock blocks. The maximum total kinetic energy of 5047 kJ has been observed in the numerical analysis with the maximum run-out distance up to 18 m.

关键词： Rockfall hazards Rockfall simulation Rockfall hazard rating system(RHRS) Road cut slopes Slope stability

Dynamic response of support systems during excavation of underground openings

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Journal of Rock Mechanics and Geotechnical Engineering 2019年第5期11卷 954-964页

作者： ?.Aydan Department of Civil Engineering University of Ryukyus

Rockburst,earthquake and blasting cause some dynamic loads on rock support and rock reinforcement system.Elements of rock support and rock reinforcement are generally made of steel bar or cables,which are resistant against corrosion.These support elements may be subjected to vibrations induced by turbines,vehicle traffic and long-term corrosion in addition to dynamic loading caused by earthquake,rockburst and blasting.In this study,some theoretical,numerical and experimental studies are conducted on rockbolts and rock anchors under shaking and impulsive loading.Then the outcomes of these studies are presented and their practical implications are discussed accordingly.

关键词： Rockbolt Dynamic behaviour Pull-out test Planar sliding Underground openings slopes

Quantitative human risk analysis of 2015 Shenzhen dump failure considering influence of urbanization

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Journal of Mountain Science 2021年第6期18卷 1439-1457页

作者： ZHANG Shuai LIU Ying BATE Bate PENG Da-lei LI Can ZHAN Liang-tong MOE Key Laboratory of Soft Soils and Geo-Environmental Engineering Zhejiang UniversityHangzhou 310058China Faculty of Science and Technology Technological and Higher Education Institute of Hong KongHongkong 999077China Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHongkong 999077China

With the rapid development of urbanization, a large amount of construction spoil was stockpiled around cities and formed extensive dumps. Construction spoil is one of the main construction and demolition(C&D) waste and municipal solid waste(MSW). Once the construction spoil dump becomes unstable, it will bring great risks to the surrounding residents. A catastrophic dump failure occurred on 20 December 2015 in Guangming New Strict, Shenzhen, China. Approximately 2.51×10^(6) m^(3) of construction waste slid out from the dumpsite, destroying 33 houses and causing total 77 casualties. This paper attempts to analyze the failure probability of the construction spoil dump using Monte Carlo simulation considering the spatial variability of soil properties, and to quantify the dynamic human risk considering the increasing urbanization. Influence of urbanization on the human element at risk is analyzed by referring to multi-temporal remote sensing images. A quantitative human risk assessment model is employed to determine the landslide human risk referring an assessment criteria curve between frequency of number fatalities and number of fatalities(F-N curve). It is found that the societal risk at daytime was 0.078, 0.088, and 1.432 in 2002, 2014, and 2015, respectively. Meanwhile, the societal risk at night was 0.034, 0.037, and 0.611 in 2002, 2014, and 2015, respectively. The quantitative method was benchmarked by the other landfill failure. It implies that the human risk increased with the development of urbanization and its value at daytime was approximately twice as much as at night. The new approach for the human risk assessment provides guidance for modern MSW landfills and highlights the obvious influence of urbanization on the human risk in other areas.

关键词： Construction spoil Dumpsite slopes Landslides Stability analysis Human risk

Rock-soil slope stability analysis by two-phase random media and finite elements

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Geoscience Frontiers 2018年第6期9卷 1649-1655页

作者： Yong Liu Huawen Xiao Kai Yao Jun Hu Hong Wei State Key Laboratory of Water Resources and Hydropower Engineering Science Institute of Engineering Risk and Disaster Prevention Wuhan University Department of Civil & Environmental Engineering National University of Singapore College of Civil Engineering and Architecture Hainan University

To investigate the strong random nature of the geometric interfaces between soil and rock, a rock-soil slope is considered as a two-phase random medium. A nonlinear translation of a Gaussian field is utilized to simulate the two-phase random media, such that the soil(or rock) volume fraction and the inclination of the soil layer can be examined. The finite element method with random media incorporated as the material properties is used to determine the factor of safety of the rock-soil slope. Monte-Carlo simulations are used to estimate the statistical characteristics of the factor of safety. The failure mode of the rock-soil slope is examined by observing the maximum principal plastic strain at incipient slope failure. It is found that the critical surface of a rock-soil slope is fairly irregular, and it significantly differs from that of a pure soil slope. The factor of safety is sensitive to the soil volume faction, but it is predictable. The average factor of safety could be well predicted by the weighted harmonic average between the strength of soil and rock; the prediction model is practical and simple. Parametric studies on the inclination of the soil layer demonstrate that the most instable scenario occurs when the slope angle is consistent with the inclination of the soil layer.

关键词： slopes stability Numerical computation Statistical analysis Finite-element modelling Random fields Monte-Carlo simulations

Phytoecological evaluation with detail floristic appraisal of the vegetation arround Malam Jabba,Swat,Pakistan

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Asian Pacific Journal of Tropical Biomedicine 2011年第6期1卷 461-467页

作者： Abdur Rashid Mohammad Farooq Swati Hassan Sher Mohammad N Al-Yemeni Department of Botany University of Peshawar Department of Botany&Biodiversity Conservation University of Swat Department of Botany&Microbiology King Saud University

Objective:To determine the present status of plant communities and their possible association with the habitat in Malam Jabba,Swat,Pakistan.Methods:A study on the phytoecology was conducted in various ecologically important sites of Malam Jabba,Swat,Pakistan from 2002 to 2004.The altitude of these sites ranged from 1200 m to.1200 m.Quadrat method was used for evaluation of plants communities and the data on these attributes was converted to relative values. The plant communities were named after 3 leading species with highest importance values. Biological spectrum of the flora based on the life form was prepared by following Raunkiar's life form classes.Results:The floristic composition and structure of the study area were found to be 200 species belonging to 75 families.Asteraceae,Lamiaceae and Poaceae were important families in the study area.The biological spectrum showed that therophytic and hemicrytophytic life form and micro-nonophyllous leaf sizes were dominant in the area.The air and soil temperatures were decreasing with increasing elevation.Both the air and soil temperatures were relatively higher in south slopes than on the northeast slopes.The vegetation analysis of the area indicated eleven plant communities around the area.The present vegetation is the relics of moist temperate coniferous forest in the area.The communities reflect highly deteriorated conditions. Both the structure and composition of the surrounding vegetation were associated with the types of habitats.Conclusions:The conservation of the remaining populations of the reported communities will be best achieved by proper time of sustainable harvesting.It is only possible with the participation of local communities.

关键词： Plant communities Altitudinal variation Conservation slopes Biological spectrum Climatic conditions Phytoecological evaluation Vegetation Floristic appraisal Phytoecology Composition