Numerical simulation of Qiaotou Landslide deformation caused by drawdown of the Three Gorges Reservoir,China   总被引：6，自引：2，他引：4  

Jiwei Jiang  Dominik Ehret  Wei Xiang  Joachim Rohn  Ling Huang  Shaojun Yan  Renneng Bi 《Environmental Earth Sciences》2011,62(2):411-419

Landslides located beside reservoirs tend to be unstable or are characterized by large deformation during the drawdown process. This has been accepted by many experts. In this paper, we use Qiaotou Landslide, which is located beside the Three Gorges Reservoir (TGR), as a typical case study to investigate and predict the deformation mechanism during the drawdown process of TGR in detail. According to field investigation, the landslide mass is mainly composed of thick, loose silt and clay mixed with fragments of rock. Bedrock is mainly composed of silty sandstone. Field and laboratory tests indicate that the landslide mass has a high permeability coefficient. If the water level declines fast, intense seepage force may result. Based on these data, we establish a three-dimensional geological model of Qiaotou Landslide by FLAC^3D and perform a numerical simulation using the saturated–unsaturated fluid–solid coupling theory. For the simulation, we assume that the drawdown from 175 to 145 m takes place with a speed of 25 cm/day, which is based on the extreme water level regulation program of TGR. The simulation shows that this causes a significant deformation in the landslide mass and that the maximum displacement within the landslide is 24.2 cm. During the drawdown process, the maximum displacement zone is shifting from the upper part of the landslide where bedrock surface is steeper and thickness of loose deposits is less to the middle part of the landslide where bedrock surface is less steep and thickness of loose deposits is higher. The deformation mechanism indicates that in the early stage of the drawdown the deformation of the landslide mass is mainly caused by seepage and in the later stage mainly by consolidation.  相似文献   

Robust landslide susceptibility analysis by combination of frequency ratio,heuristic GIS-methods and ground truth evaluation for a mountainous study area with poor data availability in the Three Gorges Reservoir area,PR China   总被引：3，自引：0，他引：3  

Markus Schleier  Renneng Bi  Joachim Rohn  Dominik Ehret  Wei Xiang 《Environmental Earth Sciences》2014,71(7):3007-3023

Increasing number of geohazards, like mass movements, is one of the main environmental impacts following the impoundment of the Yangtze River and its tributaries due to the inventory of the Three Gorges Dam hydroelectric power plant. Although many cities and settlements are endangered, no detailed hazard mapping is possible because of the huge size of the affected area. Due to strongly limited data availability, a robust landslide susceptibility model was established exemplarily for the Xiangxi catchment as one of the main tributaries. The analyses were limited to translational, rotational and combined landslides in soft rock sediments because these represent the main types of mass movement activity in this area. The qualitative landslide susceptibility analysis was carried out by a combination of frequency ratio analyses and a heuristic iterative index-based method using a Geographical Information System. As conditioning factors, the parameters lithology, slope angle, -aspect, -curvature, drainage buffer distance and land use were applied. To improve the objectivity of the index-based method, the results of frequency ratio analyses were taken into consideration to assess the importance of each factor. Model verification and evaluation by ground truth enable to improve the model by iterative calculations and to identify the best performance model. Results indicate that 89 % of all known landslides are located within areas showing high susceptibility according to the best performance model. The study demonstrates that a rather simple but robust model achieves good results and is applicable for regional landslide susceptibility analyses in mountainous areas with poor data availability.  相似文献   

The influence of grain rotation on the structure of dust aggregates     

D. Paszun  C. Dominik 《Icarus》2006,182(1):274-280

We study the effect of rotation during the collision between dust aggregates, in order to address a mismatch between previous model calculations of Brownian motion driven aggregation and experiments. We show that rotation during the collision does influence the shape and internal structure of the aggregates formed. The effect is limited in the ballistic regime when aggregates can be considered to move on straight lines during a collision. However, if the stopping length of an aggregate becomes smaller than its physical size, extremely elongated aggregates can be produced. We show that this effect may have played a role in the inner regions of the solar nebula where densities were high.  相似文献   

Theory and practice of microlensing light curves around fold singularities     

M. Dominik 《Monthly notices of the Royal Astronomical Society》2004,353(1):69-86

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Can microlensing fold caustics reveal a second stellar limb-darkening coefficient?     

M. Dominik 《Monthly notices of the Royal Astronomical Society》2004,352(4):1315-1318

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Disintegration of dust aggregates in interstellar shocks and the lifetime of dust grains in the ISM     

C. Dominik  A. P. Jones  A. G. G. M. Tielens 《Astrophysics and Space Science》1995,233(1-2):155-159

We have studied to influence of grain porosity on the dust destruction mechanism in interstellar shocks. Our results show, that fluffy aggregates of dust grains can be broken up easily in shocks.  相似文献   

Bioleaching potential of bacterial communities in historic mine waste areas     

Nida Amin  Dominik Schneider  Michael Hoppert 《Environmental Earth Sciences》2018,77(14):542

Microbial activity has the potential to alter all cultural heritage in mining and metallurgy, due to metal mobilization by leaching. This communication shows the consequences of the bioleaching ability of two natural enrichments on copper slag samples from a historic ore smelting site in Sangerhausen (Mansfeld, Südharz, Saxony-Anhalt, Germany). Enrichment cultures gained from mine drainage were dominated by either the iron and sulfur-oxidizing Acidithiobacillus ferrivorans, or by the iron-oxidizing Leptospirillum. During 35 days of bioleaching in media containing copper slag pulp, inoculated with these enrichments, the change in pH and solubilized metal concentrations of the systems were monitored. Both bacterial strains were completely different from each other in their pattern of pH variation and rates of metal solubilization. The maximum removal of Cu (1725 mg/l) and Zn (715 mg/l) from copper slag substrate was achieved with enrichment culture of A. ferrivorans SCUT-1. However, maximum Mn (207 mg/l), Pb (86 mg/l), and Ni (75 mg/l) removal was observed with enrichment culture of Leptospirillum strain YQP-1. Implications for metal mobilization along with alteration of artifacts from not only historic mining areas but also aspects of decontamination and remediation are discussed.  相似文献   

Assessment of Workforce Demands to Shape GIS&T Education          下载免费PDF全文

Gudrun Wallentin  Barbara Hofer  Christoph Traun 《Transactions in GIS》2015,19(3):439-454

The Body of Knowledge for Geographic Information Science and Technology (GIS&T BoK) has been the main reference document for curriculum design in the geospatial domain. Today, the BoK is supposed to have fallen short in adequately covering the domain due to significant conceptual and technological advances in the field. Thus, several initiatives around the globe work towards an update of the GIS&T BoK. This research assesses the demands of today's GIS&T workforce across Europe to contribute to the effort of a demand‐oriented update. We assessed the workforce demand by means of a Europe‐wide distributed online questionnaire and complementary expert interviews. The results show that the BoK still is a comprehensive reference base for the geospatial domain that is generally deemed relevant by the European workforce. However, workforce demands point to three main topics that need to be addressed by an update of the BoK: (1) the shift from primary data acquisition to the handling of highly abundant spatial data; (2) a lack of competences in programming and application development; and (3) a poor coverage of web‐related aspects. Future research should complement workforce demands with a review of the scientific literature to identify additional shortcomings related to conceptual advances.  相似文献   

Adaptive contouring – an efficient way to calculate microlensing light curves of extended sources     

M. Dominik † 《Monthly notices of the Royal Astronomical Society》2007,377(4):1679-1688

The availability of a robust and efficient routine for calculating light curves of a finite source magnified due to bending of its light by the gravitational field of an intervening binary lens is essential for determining the characteristics of planets in such microlensing events, as well as for modelling stellar lens binaries and resolving the brightness profile of the source star. However, the presence of extended caustics, and the fact that the images of the source star cannot be determined analytically while their number depends on the source position (relative to the lens system), makes such a task difficult in general. Combining the advantages of several earlier approaches, an adaptive contouring algorithm is presented, which only relies on a small number of simple rules and operations on the adaptive search grid. By using the parametric representation of critical curves and caustics found by Erdl & Schneider, seed solutions to the adaptive grid are found, which ensures that no images or holes are missed.  相似文献   

Why can't we do better than Topmodel?     

Wouter Buytaert  Dominik Reusser  Stefan Krause  J.‐P. Renaud 《水文研究》2008,22(20):4175-4179

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