A multi-method approach to study the stability of natural slopes and landslide susceptibility mapping   总被引：8，自引：0，他引：8  

M. Fall  R. Azzam  C. Noubactep 《Engineering Geology》2006,82(4):241-263

In this paper, a multi-method approach for the assessment of the stability of natural slopes and landslide hazard mapping applied to the Dakar coastal region is presented. This approach is based on the effective combination of geotechnical field and laboratory works, of GIS, and of mechanical (deterministic and numerical) stability analysis. By using this approach, valuable results were gained regarding instability factors, landslide kinematics, simulation of slope failure and coastal erosion. This led to a thorough assessment and strong reduction in the subjectivity of the slope stability and hazard assessment and to the development of an objective landslide danger map of the SW coast of Dakar. Analysis of the results shows that the slides were influenced by the geotechnical properties of the soil, the weathering, the hydrogeological situation, and the erosion by waves. The landslide susceptibility assessment based on this methodological approach has allowed for an appropriate and adequate consideration of the multiple factors affecting the stability and the optimization of planning and investment for land development in the city.  相似文献   

Radiomagnetotelluric mapping, groundwater numerical modelling and 18-Oxygen isotopic data as combined tools to determine the hydrogeological system of a landslide prone area     

P. Tullen  P. Turberg  A. Parriaux 《Engineering Geology》2006,87(3-4):195-204

Three methods were combined to determine the groundwater recharge and transfer processes of a landslide prone area. First, the radiomagnetotelluric method was used to investigate the distribution of electrical resistivity (ρ) of the subsurface and build a three-dimensional model of permeability (k), through an experimental relation between ρ and k. Second, this structural model of permeability and additional climatologic data were used to fix boundary and recharge conditions to perform a three-dimensional and transient numerical simulation of the groundwater flow. Finally 18-Oxygen time series observed at the main springs were used to validate the model. This association of methods led to an improved characterization of the groundwater flow system at local scale and a better understanding of the role of this system on the landslide phenomenon. This structured approach is thought to be useful to design specific remediation strategies to drain the unstable mass.  相似文献   

2D Self-Potential tomographies for studying groundwater flows in the Varco d''Izzo landslide (Basilicata, southern Italy)     

G. Colangelo  V. Lapenna  A. Perrone  S. Piscitelli  L. Telesca 《Engineering Geology》2006,88(3-4):274-286

A geoelectrical monitoring activity has been carried out to improve the geological and hydrogeological knowledge about the Varco d'Izzo landslide (Potenza, Basilicata, Southern Apennine, Italy), an active rotational–translational slide evolved in earth-flow. In this work we have focused on the Self-Potential (SP) method by applying three different SP measuring techniques and combining modern technologies for data acquisition and new methods for tomographic inversion. A SP map and three static SP tomographies have been carried out to better analyse the groundwater circulation system and to better reconstruct the geometry of the landslide body. In the accumulation zone, which is the area more exposed to the geomorphological activity, a new SP measuring strategy has been applied. This strategy, based on time-continuous 2D SP tomographies, helps identify water flow changes in subsurface by studying the time series of SP tomographic images. The analysis of time-dependent changes of water infiltration in near surface is the key to better understand the hydrogeological processes underlying the ground instability phenomena. The time-lapse analysis of tomographic images has allowed us not only to investigate the correlation between the temporal changes of SP signals and rainfall events, but also to quantify the range of these changes. The modification of the distribution of the SP source accumulation zones is associated with the dynamics of the groundwater flows. These preliminary results allow us to consider the SP tomographic method as a tool for geophysical monitoring of landslide areas and encourage to develop new measuring systems for near-real time applications.  相似文献   

Fracture and bedding plane control on groundwater flow in a chalk aquitard     

Menachem Weiss  Yoram Rubin  Eilon Adar  Ronit Nativ 《Hydrogeology Journal》2006,14(7):1081-1093

Shallow groundwater in the northern Negev desert of Israel flows preferentially through a complex system of discontinuities. These discontinuities intersect what would otherwise be a massive, low-conductivity, high-porosity Eocene chalk. Vertical fractures and horizontal bedding planes were observed and mapped along approximately 1,200 m of scanline, 600 m of core and 30 two-dimensional trace planes. A bimodal distribution of size exists for the vertical fractures which occur as both single-layer fractures and multi-layer fractures. A bimodal distribution of log transmissivity was observed from slug tests conducted in packed-off, vertical intervals within the saturated zone. The different flow characteristics between the horizontal bedding planes and vertical-type fractures appear to be the cause of the bimodality. Two distinct conceptual models (discrete fracture network) were developed based on the fracture orientation, size, intensity and transmissivity statistics derived from field data. A correlation between fracture size and hydraulic aperture was established as the basis for calibrating the simulated model transmissivity to the field observations. This method of defining transmissivity statistically based on prior information is shown to be a reasonable and workable alternative to the usual conjecture approach towards defining transmissivity in a fractured-rock environment.  相似文献   

A GIS-based automated procedure for landslide susceptibility mapping by the Conditional Analysis method: the Baganza valley case study (Italian Northern Apennines)   总被引：14，自引：0，他引：14  

Aldo Clerici  Susanna Perego  Claudio Tellini  Paolo Vescovi 《Environmental Geology》2006,50(7):941-961

  相似文献   

Slope instability of San Miniato hill (Florence, Italy): possible deformation patterns   总被引：1，自引：1，他引：1  

Riccardo Fanti 《Landslides》2006,3(4):323-330

The hill of San Miniato (Florence, Italy) has been repeatedly identified in the past as the site of a slow moving, intermittent landslide. Possible hypotheses regarding the mechanisms responsible for past movements and for cracks and fissures present today are formulated based on the comparison of historical information and processed monitoring data. Although it is not possible to completely exclude a large inactive landslide that involves the entire northern slope, it seems more probable that the slide, if it does exist, is no longer active and that present-day damage is due to separate shallow movements concentrated in man-made deposits. This hypothesis can only be verified with a temporal extension of the monitoring activities, necessary in any case for planning possible safeguarding measures for the cultural heritage in the area.  相似文献   

The 1786 earthquake-triggered landslide dam and subsequent dam-break flood on the Dadu River, southwestern China — Reply     

F.C. Dai  C.F. Lee  J.H. Deng  L.G. Tham 《Geomorphology》2006,73(3-4):277-278

A short reply to discussion by Chanson.  相似文献   

Cellular automata as analysis and synthesis engines at the geomorphology–ecology interface     

Mark A. Fonstad   《Geomorphology》2006,77(3-4):217

The linkages between ecology and geomorphology can be difficult to identify because of physical complexity and the limitations of the current theoretical representations in these two fields of study. Deep divisions between these disciplines are manifest in the methods used to simulate process, such as rigidly physical-deterministic methods for many aspects of geomorphology compared with purely stochastic simulations in many models of change in landcover. Practical and theoretical research into ecology–geomorphology linkages cannot wait for a single simulation schema which may never come; as a result, studies of these linkages often appear disjointed and inconsistent.The grid-based simulation framework for cellular automata (CA) allows simultaneous use of competing schemas. CA use in general geographic studies has been primarily limited to urban simulations models of change for land cover, both highly stochastic and/or expert rule-based. In the last decade, however, methods for describing physically deterministic systems in the CA framework have become much more accurate. The possibility now exists to merge separate CA simulations of different environmental systems into unified “multiautomata” models. Because CAs allow transition rules that are deterministic, probabilistic, or expert rule-based, they can immediately incorporate the existing knowledge rules in ecology and geomorphology. The explicitly spatial nature of CA provides a map-like framework that should allow a simple and deeply rooted connection with the mapping traditions of the geosciences and ecological sciences.  相似文献   

土壤天然热释光测量在寻找滑坡体边界中的应用研究   总被引：1，自引：1，他引：1  

张丽娇  叶树林  刘庆成 《工程地质学报》2006,14(6):815-818

土壤天然热释光测量方法是一种累积型测氡方法。由于累积测氡时间长,其灵敏度和异常的重现性远比一般累积测氡及其子体方法好,因此,在地质领域得到了广泛的应用。在寻找滑坡体边界的应用中,取得的测量效果明显,表明该方法经济有效。  相似文献   

Modeling of rainfall-triggered shallow landslide   总被引：5，自引：3，他引：5  

Tung-Lin Tsai  Jinn-Chuang Yang 《Environmental Geology》2006,50(4):525-534

By integrating hydrological modeling with the infinite slope stability analysis, a rainfall-triggered shallow landslide model was developed by Iverson (Water Resour Res 36:1897-1910, 2000). In Iverson’s model, the infiltration capacity is assumed to be equivalent to the saturated hydraulic conductivity for finding pressure heads analytically. However, for general infiltration process, the infiltration capacity should vary with time during the period of rain, and the infiltration rate is significantly related to the variable infiltration capacity. To avoid the unrealistically high pressure heads, Iverson employed the beta-line correction by specifying that the simulated pressure heads cannot exceed those given by the beta line. In this study, the suitability of constant infiltration capacity together with the beta-line correction for hydrological modeling and landslide modeling of hillslope subjected to a rainfall is examined. By amending the boundary condition at ground surface of hillslope in Iverson’s model, the modified Iverson’s model with considering general infiltration process is developed to conduct this examination. The results show that the unrealistically high pressure heads from Iverson’s model occur due to the overestimation of infiltration rate induced from the assumption that the infiltration capacity is identical to the saturated hydraulic conductivity. Considering with the general infiltration process, the modified Iverson’s model gives acceptable results. In addition, even though the beta-line correction is applied, the Iverson’s model still produces greater simulated pressure heads and overestimates soil failure potential as compared with the modified Iverson’s model. Therefore, for assessing rainfall-triggered shallow landslide, the use of constant infiltration capacity together with the beta-line correction needs to be replaced by the consideration of general infiltration process.  相似文献