查看更多>>摘要：? 2022 Elsevier B.V.As a potential destructive secondary hazard initiated by earthquakes, earthquake-triggered landslides can cause significant losses. Seismic landslide hazard maps are important for land use planning and landslide hazard reduction in tectonically active areas. A comprehensive probabilistic seismic landslide hazard mapping approach incorporating the uncertainties of slope properties and displacement prediction is required to promote the application of hazard maps. Based on the definition of the critical slope angle, this paper proposes an alternative seismic landslide hazard category considering the uncertainty of geotechnical properties of soil using Monte Carlo simulations and incorporating the ground motion variability based on the displacement hazard curve. The proposed new hazard category is applied to the region of Anchorage, Alaska, for the seismic landslide hazard mapping process. Subsequently, parameter analyses are performed to explore the sensitivity among the factors that contributed to the seismic landslide hazard map. The results of seismic landslide hazard maps show that the area of hazardous zone of most geologic units in present study is smaller than that in the deterministic analysis. Comparing with the probabilistic method using logic tree analysis, the proposed approach using Monte Carlo simulations predicts different landslide hazardous zone due to the probabilistic distribution of geotechnical properties of soil. The predicted hazardous zone is also sensitive to the resolution of the digital elevation model and different coefficient of variation combinations.
查看更多>>摘要：? 2022 Elsevier B.V.The challenge in intelligent cities is to recognize the benefits of using big data. The management of big datasets enables efficient data storage and processing to enhance information for the decision-making process. The key aim of this paper is to highlight how geological, engineering geological and geotechnical knowledge can be managed in a well-organized database, which is able to develop various correlations and to present useful information for both the design and construction stages of important projects of civil protection, municipality and technical companies. The present paper demonstrates the implementation of such work in the city of Thessaloniki, northern Greece, where a large amount of geological and geotechnical data for more than 600 boreholes, mainly based on borehole geological information, laboratory testing, geotechnical characterization and in situ field tests collected from fill, Quaternary and Neogene deposits, is stored in a georeferenced database. The presented database, is targeted to the management and processing of geo-engineering datasets for various geotechnical projects but also for the protection against natural hazards. The purpose of the approach, besides incorporating multisource datasets, is to provide a tool to effortlessly and immediately analyze, correlate and display data on maps, tables and diagrams for stakeholders. For this analysis, the present study proposes a geographic information system approach coupling the use of geostatistical techniques along with the cross validation to establish geotechnical zonation maps in order to highlight hazardous areas prone to liquefaction and settlement and to indicate the site's adaptability for different infrastructure projects. In that context, specific value ranges for several physical and mechanical properties are proposed from the assessment and correlation of the information originating from the database and spatial variability, providing geological and geotechnical knowledge in safe urban extensions suitable for construction in the research area environment. However, the key challenge is not only referring to provide each influencing parameter with a quantitative range of values, but also to establish a set of reliable structural and high-precision informative geotechnical models to comprehensively understand the superficial and subsurface conditions of the research area.
查看更多>>摘要：? 2022 The AuthorsThis paper applies remote sensing techniques and 3D point cloud (3DPC) analysis to the study of historical quarries and the relationship between old quarry landscapes and the natural fracture systems of rock massifs. Ancient quarry landscapes present particular characteristics and different features from those of modern quarries. Consequently, specific considerations are needed when historical extractive places are studied. The proposed method is based on terrestrial 3D laser scanners and the structure from motion technique with remotely piloted aircraft systems. Additional specific fieldwork is required to identify and characterise quarry faces from old, blurry outcrops. A case study of the 18th century “Rambla Honda” quarries in La Romana (Alicante, SE Spain) is presented. The comparison between the fieldwork and 3DPC analysis enables the numbers and orientations of both (1) the discontinuity sets within the rock mass facilitating extraction and (2) the planes resulting from block extraction (traditional quarry faces) to be determined. The comparative analysis reveals how the stonecutters managed the extraction. The results show that structural and stratigraphic discontinuities act as planes of weakness for block extraction and determine the optimum orientation of the quarry face for minimising efforts and rock waste. The final quarry landscape is formed from the superposition of natural and artificial surfaces, but currently they appear eroded and partially covered by silting and plants. The proposed methodology contributes to distinguishing both natural and artificial discontinuities and to achieving a comprehensive knowledge of these cultural places.
查看更多>>摘要：? 2022 Elsevier B.V.Erosive processes have long been considered an important control on landslide activity in coastal environments. Despite its importance and numerous coastal failures in recent years, there has been limited quantitative characterization of the feedbacks between coastal erosion and the commensurate advance of active landslides. Quantitatively understanding the role of erosion as a control on the advance of coastal landslides is imperative from both hazard assessment and geomorphic perspectives, particularly considering future projections of increased erosion from sea level rise. Using a three-dimensional slope stability model coupled with a mass-conserving finite difference analysis, we constrain landslide advance in response to erosion and evolving landslide geometry. We identified an inversely proportional relationship between landslide volume and magnitude of advance for a given level of toe retreat. Landslide aspect ratio and geometry may exert a second-order control on sensitivity of advance to coastal erosion. Further, in comparison to observed landslide advance of three well-characterized landslides in Oregon, the proposed relationships provide insights towards the relative importance of erosion versus other disturbances, such as groundwater rise. Our findings provide insight towards the dynamics of landslides in coastal environments to advance regional coastal landslide hazard and risk assessments.
查看更多>>摘要：? 2022This paper introduces a preparation method of a transparent soil-rock mixture (T-SRM) for geotechnical laboratory modeling. The T-SRM uses n-dodecane and white oil as the fluid phase, amorphous silica powder as the soil phase, and quartz glass particle as the rock block phase. The T-SRM sample prepared using the proposed method is of good transparency: the glass particles are “disappeared” under visible light, whereas their outlines are clearly evident when using a laser light sheet slicing the sample. A series of direct shear tests were carried out to investigate the mechanical behaviors of the T-SRM. It is found that the pre-consolidation pressure during preparation is of significant influence on the mechanical strength of T-SRMs, and by adjusting the value of pre-consolidation pressure, we can obtain T-SRM samples with different mechanical strengths. A trial test shows that, by controlling the rock content and block size close to that of natural SRM and adjusting the pre-consolidation pressure during the preparing process, the T-SRM sample with similar mechanical strength to that of natural SRM can then be obtained, which demonstrates the practicability of using the proposed material in the visualization of SRM in modeling tests.
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