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Prediction of the residual strength of clay using functional networks

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Geoscience Frontiers 2016年第1期7卷 67-74页

作者： S.Z.Khan Shakti Suman M.Pavani S.K.Das Civil Engineering Department BIETBPUT Civil Engineering Department National Institute of Technology Rourkela

landslides are common natural hazards occurring in most parts of the world and have considerable adverse economic effects. Residual shear strength of clay is one of the most important factors in the determination of stability of slopes or landslides. This effect is more pronounced in sensitive clays which show large changes in shear strength from peak to residual states. This study analyses the prediction of the residual strength of clay based on a new prediction model, functional networks（FN） using data available in the literature. The performance of FN was compared with support vector machine（SVM） and artificial neural network（ANN） based on statistical parameters like correlation coefficient（R）, Nash–Sutcliff coefficient of efficiency（E）, absolute average error（AAE）, maximum average error（MAE） and root mean square error（RMSE）. Based on R and E parameters, FN is found to be a better prediction tool than ANN for the given data. However, the R and E values for FN are less than SVM. A prediction equation is presented that can be used by practicing geotechnical engineers. A sensitivity analysis is carried out to ascertain the importance of various inputs in the prediction of the output.

关键词： landslides Residual strength Index properties Prediction model Functional networks

The landslide problem

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Journal of Palaeogeography 2015年第2期4卷 109-166页

作者： G.Shanmugam Department of Earth and Environmental Sciences The University of Texas at Arlington

The synonymous use of the general term ＂landslide＂, with a built-in reference to a sliding motion, for all varieties of mass-transport deposits （MTD）, which include slides, slumps, debrites, topples, creeps, debris avalanches etc. in subaerial, sublacustrine, sub- marine, and extraterrestrial environments has created a multitude of conceptual and nomen- clatural problems. In addition, concepts of triggers and Iong-runout mechanisms of mass movements are loosely applied without rigor. These problems have enormous implications for studies in process sedimentology, sequence stratigraphy, palaeogeography, petroleum geol- ogy, and engineering geology. Therefore, the objective of this critical review is to identify key problems and to provide conceptual clarity and possible solutions. Specific issues are the fol- lowing：（1） According to ＂limit equilibrium analyses＂ in soil mechanics, sediment failure with a sliding motion is initiated over a shear surface when the factor of safety for slope stability （F） is less than 1. However, the term landslide is not meaningful for debris flows with a flowing mo- tion. （2） Sliding motion can be measured in oriented core and outcrop, but such measurement is not practical on seismic profiles or radar images. （3） Although 79 MTD types exist in the geological and engineering literature, only slides, slumps, and debrites are viable depositional facies for interpreting ancient stratigraphic records. （4） The use of the term landslide for high- velocity debris avalanches is inappropriate because velocities of mass-transport processes cannot be determined in the rock record. （5） Of the 21 potential triggering mechanisms of sediment failures, frequent short-term events that last for only a few minutes to several hours or days （e.g., earthquakes, meteorite impacts, tsunamis, tropical cyclones, etc.） are more relevant in controlling deposition of deep-water sands than sporadic long-term events that last for thousands to millions of years （e.g., sea-level Iowstands）. （6） The comparison of HIL

关键词： debris flows landslides mass-transport deposits （MTD） slides slumps soilstrength triggering mechanisms reservoir characterization

Mapping Natural Hazard Impacts on Road Infrastructure——The Extreme Precipitation in Baden-Württemberg, Germany, June 2013

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International Journal of Disaster Risk Science 2014年第3期5卷 227-241页

作者： Sina Keller Andreas Atzl Institute of Regional Science/Institute of Urban and Regional Planning Karlsruhe Institute of TechnologyKaiserstraße 1276131 KarlsruheGermany

Infrastructures in Europe have been affected by impacts of extreme natural events with increasing frequency over the past decades. One of the most recent examples is the flooding that affected parts of Germany in June 2013. Global warming is expected to change patterns of climate-related extreme events affecting infrastructure.This article presents an explanatory approach. Based on an observational design, causal connections between the occurrence and patterns of extreme events and related road infrastructure impacts are analyzed. The hazard mapping case study in the state of Baden-Wrttemberg combines traffic information and data on the June 2013 extreme precipitation in Germany. It examines the precipitation occurrence and road infrastructure impact characteristics in Baden-Wu¨ rttemberg and identifies spatiotemporal hazard patterns. The article suggests further research needs and fields of application for risk mapping in climate change adaptation research in Germany.

关键词： Extreme precipitation Floods Germany Hazard patterns landslides Road infrastructure

Stability assessment of landslide-prone road cut rock slopes in Himalayan terrain:A finite element method based approach

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 59-73页

作者： Sarada Prasad Pradhan Tariq Siddique Department of Earth Sciences Indian Institute of Technology RoorkeeRoorkee247667India Department of Geology Aligarh Muslim UniversityAligarh202002India

Large-scale slope destabilization could be aggravated due to swift urbanization and ever-rising demands of geoengineering projects such as dams,tunnels,bridges and widening roads.National Highway-58 connects Delhi to Badrinath in India,which passes through complex geomorphological and geological terrain and often encounters cut slopes susceptible to slope failures.In the present investigation,a detailed geotechnical appraisal is conducted along the road cut slopes from Rishikesh to Devprayag in the Himalayas.Twenty vulnerable road cut slopes were demarcated for detailed slope stability analysis using Phase2D finite element modeling simulator.Nonlinear generalized Hoek-Brown(GHB)criterion was adopted for stability analyses.Out of 20 slopes,five slopes(S6,S7,S18,S19 and S20)are unstable with factor of safety(FoS)less than or equal to 1,and thus needs immediate attention.The FoS values of four slopes(S2,S9,S13 and S17)lie between 1 and 1.3,i.***.marginally stable,and slopes S1,S3,S4,S5,S8,S10,Sll,S12,S14,S15 and S16 are stable.Mohr-Coulomb(MC)criterion was also adopted to compare the slope stability analysis with GHB criterion.The FoS calculated from GHB criterion is close to that using MC criterion for lower values of FoS whereas for higher values,the difference is marked.For the jointed rock in the Himalayan region,the nonlinear GHB criterion gives better results as compared to MC criterion and matches with the prevailing field conditions.Accordingly,some suggestions are proposed to strengthen the stability of cut slopes.

关键词： landslides Numerical modeling Finite element method(FEM) Slope stability

Probabilistic seismic landslide hazard assessment: a case study in Tianshui, Northwest China

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Journal of Mountain Science 2020年第1期17卷 173-190页

作者： WANG Tao LIU Jia-mei SHI Ju-song GAO Meng-tan WU Shu-ren Institute of Geomechanics Chinese Academy of Geological SciencesBeijing 100081China Key Laboratory of Active Tectonics and Crustal Stability Assessment Institute of Geomecha nicsCAGSBeijing 100081China China Institute for Geo-Enviro nmental Monitoring Beijing 100081China Institute of Geophysics China Earthquake AdministrationBeijing 100081China

Probabilistic analysis in the field of seismic landslide hazard assessment is often based on an estimate of uncertainties of geological, geotechnical,geomorphological and seismological parameters.However, real situations are very complex and thus uncertainties of some parameters such as water content conditions and critical displacement are difficult to describe with accurate mathematical models. In this study, we present a probabilistic methodology based on the probabilistic seismic hazard analysis method and the Newmark’s displacement model. The Tianshui seismic zone(105°00′-106°00′ E, 34°20′-34°40′ N) in the northeastern Tibetan Plateau were used as an example. Arias intensity with three standard probabilities of exceedance(63%, 10%, and 2% in 50 years) in accordance with building design provisions were used to compute Newmark displacements by incorporating the effects of topographic amplification.Probable scenarios of water content condition were considered and three water content conditions(dry,wet and saturated) were adopted to simulate the effect of pore-water on slope. The influence of 5 cm and 10 cm critical displacements were investigated in order to analyze the sensitivity of critical displacement to the probabilities of earthquake-induced landslide occurrence. The results show that water content in particular, have a great influence on the distribution of high seismic landslide hazard areas. Generally, the dry coverage analysis represents a lower bound for susceptibility and hazard assessment, and the saturated coverage analysis represents an upper bound to some extent. Moreover, high seismic landslide hazard areas are also influenced by the critical displacements. The slope failure probabilities during future earthquakes with critical displacements of 5 cm can increase by a factor of 1.2 to 2.3 as compared to that of 10 cm. It suggests that more efforts are required in order to obtain reasonable threshold values for slope failure. Considering the probable scenarios of water content condition which is

关键词： Probabilistic analysis Seismic hazard Newmark’s method landslides Displacement model Hazard assessment

Robust design of self-starting drains using Random Forest

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Journal of Mountain Science 2021年第4期18卷 973-989页

作者： GE Qi LIU Zhong-qiang SUN Hong-yue LANG Dominik SHUAI Fei-xiang SHANG Yue-quan ZHANG Ying-qiu College of Civil Engineering and Architecture Zhejiang University 310058 HangzhouChina Norwegian Geotechnical Institute Oslo 0855Norway Ocean College Zhejiang UniversityZhoushan 316021China

Groundwater lowering is one of the most important countermeasures to avoid the risk of rainfall-triggered landslides.However,the long-term reliability of many drainage methods is often a matter of concern since the drains may easily get clogged.A new hydraulic-driven self-starting drainage method is presented in this paper.In the proposed Random Forest(RF)based robust design approach for the selfstarting drains,the datasets are generated using an automatically controlled numerical modeling technology.The deterministic analysis is carried out based on uncertain soil parameters and the specific designs selected using Uniform Design(UD).The ensemble of RF models is applied in the design process to improve computing efficiency.Safety requirements,design robustness,and cost efficiency are simultaneously considered utilizing multiobjective optimization.A straightforward and efficient framework that focuses on difficulties caused by an enormous design space is established for the robust design of the self-starting drains,and improved computation efficiency is achieved.The effectiveness of the proposed approach is illustrated with a case study,the Qili landslide in Zhejiang Province,China.

关键词： landslides Self-starting drains Random Forest Robust geotechnical design

Landslide inventory and susceptibility assessment using multiple statistical approaches along the Karakoram highway,northern Pakistan

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Journal of Mountain Science 2021年第3期18卷 583-598页

作者： Mian Luqman HUSSAIN Muhammad SHAFIQUE Alam Sher BACHA CHEN Xiao-qing CHEN Hua-yong National Centre of Excellence in Geology University of PeshawarPeshawar 25130Pakistan Institute of Mountain Hazards and Environment Chinese Academy of SciencesChengdu 610041China

China-Pakistan Economic Corridor(CPEC)is a framework of regional connectivity,which will not only benefit China and Pakistan but will have positive impact on Iran,Afghanistan,India,Central Asian Republic,and the region.The surrounding area in CPEC is prone to frequent disruption by geological hazards mainly landslides in northern Pakistan.Comprehensive landslide inventory and susceptibility assessment are rarely available to utilize for landslide mitigation strategies.This study aims to utilize the high-resolution satellite images to develop a comprehensive landslide inventory and subsequently develop landslide susceptibility maps using multiple techniques.The very high-resolution(VHR)satellite images are utilized to develop a landslide inventory using the visual image classification techniques,historic records and field observations.A total of 1632 landslides are mapped in the area.Four statistical models i.e.,frequency ratio,artificial neural network,weights of evidence and logistic regression were used for landslide susceptibility modeling by comparing the landslide inventory with the topographic parameters,geological features,drainage and road network.The developed landslides susceptibility maps were verified using the area under curve(AUC)method.The prediction power of the model was assessed by the prediction rate curve.The success rate curves show 93%,92.8%,92.7%and 87.4%accuracy of susceptibility maps for frequency ratio,artificial neural network,weights of evidence and logistic regression,respectively.The developed landslide inventory and susceptibility maps can be used for land use planning and landslide mitigation strategies.

关键词： landslides Inventory map Susceptibility assessment Northern Pakistan CPEC

Probabilistic Study of Landslide Susceptibility in the Sagrado River Watershed,Brazil

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Journal of Environmental Science and Engineering(A) 2023年第3期12卷 92-99页

作者： Maiely Minozzo Vitor Pereira Faro Federal University of Paraná Curitiba-PR82590-300Brazil

In this paper,we present a probabilistic study of landslide susceptibility at the Sagrado River Watershed in Morretes,Brazil.The area is characterized by slopes higher than 20%in a large part of the relief,variable soil depths,and by strong rainfall intensities due to orographic rains.Taken together,these factors promote the occurrence of translational landslides.Anthropic occupation is distributed along the lowlands and on the less inclined slopes of the Serra do Mar.The infinite slope method was used to determine the distribution of susceptibility to landslides.Input parameters of the model consisted of geotechnical soil parameters,soil layer thickness,slope of the hillside,and matric suction,and the analysis implemented a Monte Carlo probabilistic method.As such,this method allows the quantification of uncertainties due to the variability in geotechnical parameters,which enables the determination of a probability of rupture.The elaboration of susceptibility maps to landslides for unsaturated soil conditions represents a useful tool to support the identification of critical events occurrences in this location.

关键词： Monte Carlo method landslides susceptibility assessment probabilistic analysis

A GIS tool for infinite slope stability analysis(GIS-TISSA)

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Geoscience Frontiers 2021年第2期12卷 756-768页

作者： Rüdiger Escobar-Wolf Jonathon D.Sanders C.L.Vishnu Thomas Oommen K.S.Sajinkumar Department of Geological and Mining Engineering and Sciences Michigan Technological UniversityHoughtonMIUSA Department of Geology University of KeralaThiruvananthapuram 695581KeralaIndia

landslides are one of the most common and a destructive natural hazard in mountainous terrain and thus evaluating their potential locations and the conditions under which they may occur is crucial for their hazard assessment.Shallow landslide occurrence in soil and regolith covered slopes are often modeled using the infinite slope model,which characterizes the slope stability in terms of a factor of safety(FS) value.Different approaches have been followed to also assess and propagate uncertainty through such models.Haneberg(2004) introduced the use of the First Order Second Moment(FOSM) method to propagate input uncertainty through the infinite slope model,further developing the model and implementing it in the PISA-m software package(Haneberg,2007).Here we present an ArcPy implementation of PISA-m algorithms,which can be run from ESRI ArcMap in an entirely consistent georeferenced framework,and which we call "GIS Tool for Infinite Slope Stability Analysis"(GIS-TISSA).Users can select between different input options,e.g.,following a similar input style as for PISA-m,i.e., using an ASCII.csv parameters input file,or providing each input parameter as a raster or constant value,through the program graphic user interface.Analysis outputs can include FS mean and standard deviation estimates,the probability of failure(FS landslides fell in zones identified by the model

关键词： landslides GIS-TISSA PISA-m FOSM Factor of Safety