European capital cities as political frontiers     

Gertjan Dijkink 《GeoJournal》2000,51(1-2):65-71

The capital is the centre of the established order but it always had to accept a relatively uncontrollable world of individuals redefining urban space in their own way or pioneering new means of support. As their existence is both a political nuisance and a foreshadowing of institutional changes (sometimes revolutionary) of nation-wide importance, I call such ways of life political frontiers. One may wonder what will become of political frontiers in the information society (or postmodern society) that, apart from borderless, has been described as society without a centre as well. Actually information society is the prototype of a frontier society with self-responsible groups and individuals. However, capitals – even stripped of their governmental functions – may offer a symbolical environment (a condensation of space and time) that precisely satisfies the wants of those who wish to politicise a way of life. Niches for pioneering behaviour may get dispersed over a wider territory but new types of political activity will gravitate to the capital even if the capital's official political status has dwindled.  相似文献   

Influence of earthquakes on the stability of slopes   总被引：2，自引：0，他引：2  

Robert Hack  Dinand Alkema  Gerard A.M. Kruse  Noud Leenders  Lucia Luzi 《Engineering Geology》2007,91(1):4-15

Earthquakes are a major trigger for instability of natural and man-made slopes. Often the instability of slopes due to an earthquake causes more destruction and kills more people than the actual earthquake itself. A comparison is made between different methodologies to analyze the potential stability of slopes during earthquakes. Theoretically, it seems simple to calculate the stability of a slope during an earthquake. In reality, however, the stability is influenced by so many parameters that are either not known or which influence is so poorly known that a decent estimation of stability cannot be made. Offshore the situation is worse because proper data required for stability calculations are even less available than onshore. On- and offshore, erosion and weathering create continuously slopes that may become unstable during a future earthquake, offshore also sedimentation creates continuously new slopes. Another fundamental problem in stability analysis is the complicated and largely unknown behavior of seismic waves in three-dimensions in natural materials. The lack of accurate data and the unknown behavior of seismic waves in three-dimensions make estimations of slope stability during an earthquake unreliable.  相似文献   

江苏镇江焦山索道上站滑坡治理中技术方法的应用     

张剑 《江苏地质》2007,31(3):281-284

镇江市是江苏省滑坡地质灾害较为严重的城市,其地质灾害防治工作开展较早,积累了一定的防治管理经验。而焦山索道上站滑坡治理工程是多种滑坡治理技术方法和措施的综合应用,通过混凝土抗滑桩、锚索、锚杆、排水以及挂网喷播复绿等技术方式和措施的应用,成功地完成了焦山索道上站的滑坡治理工程,为镇江市其他滑坡地质灾害的治理提供了一定的参考借鉴作用。  相似文献   

North-south transfer zones and paleo-morphological reconstruction of the Xylokastro area (Corinth Gulf, Greece)     

Joachim Place  Yves Graud  Marc Diraison  Laurence Warr 《Tectonophysics》2007,440(1-4):121-139

A large number of studies have documented the structural and sedimentary architecture of the Corinth Gulf, especially the major E–W trending normal faults important in accommodating the main extensional strain and associated growth of the Gilbert fan deltas. However, the role of several N–S oriented structures that crop out at the surface and are detectable at depth by seismic reflection and gravity surveys are not clearly understood. Based on new geological data, collected near Xylokastro, we describe the N–S oriented tectonic activity of this area. The mapped inland faults correspond to off-shore structures identified in re-interpreted seismic lines and appear to have acted as a major transfer zone during the opening of the Corinth Gulf. Reconstruction of the paleo-topography based on sedimentary facies and the environment of clay mineral formation suggest these transfer zones played an important role in controlling both local structural relief and depositional conditions of the Gilbert fan deltas.  相似文献   

Experimental study on the effects of artificial bed roughness on turbidity currents over abrupt bed slope change     

《国际泥沙研究》2020,35(3):256-268

A series of experimental observations are presented in the current study to discuss the effects of artificial bed roughness on the turbidity current flowing in a rectangular channel with an abrupt change in bed slope.For this purpose,two different types of elements,sinusoidal and trapezoidal,with various heights and arrangements are considered as artificial bed roughness.A Vectrino velocity meter was used to measure the velocity and sediment concentration profiles.The effects of inlet sediment concentration on front velocity,body velocity,unit discharge,sediment concentration,and suspended load transport rate also were investigated.Accurate equations were developed for estimation of the velocity of a turbidity current over smooth and rough beds.The unexpected experimental results showed that unlike the effect of roughness height,a change in the roughness arrangement has no significant influence on the velocity of a turbidity current.Also,the effect of bed roughness on the front velocity of a denser current is more significant.  相似文献   

边坡稳定性优势面分析与专家系统推理策略     

璩继立 《南方国土资源》1998,(2)

文章对边坡稳定性优势面分析与评价的专家系统及其推理策略和实现过程进行了阐述;并对在实现过程及实际应用中的技术问题进行了探讨。  相似文献   

Modelling of hillslope runoff processes   总被引：3，自引：0，他引：3  

N. M. Shakya  S. Chander 《Environmental Geology》1998,35(2-3):115-123

 The present study is aimed at modelling hillslope flows with emphasis on subsurface stormflows that involve macropores. The physical processes connected with the runoff process on a hillslope are identified. The components which are considered in modelling the hillslope flow are the nature of flows in the macropore and micropore domains, the spatial and temporal characteristics of the macropore network, the interaction between the domains, and the initiation of flow in the macropores. Both Horton and Dunne's variable source area generation mechanisms are explicitly incorporated in the model. The dominant physical processes governing hillslope runoff are conceptualized in terms of parameters which are derived from the physical properties of the soil, the nature of macropores, and hillslope geometry. The conceptualization of the model is then used to examine infiltration and runoff production. This helps to compute the development of the groundwater table, runoff hydrograph, and soil moisture profile. Received: 5 October 1996 · Accepted: 25 June 1997  相似文献   

Regionalization of rainfall thresholds: an aid to landslide hazard evaluation   总被引：25，自引：2，他引：23  

Giovanni Crosta 《Environmental Geology》1998,35(2-3):131-145

 Rainfall, soil properties, and morphology are major factors controlling shallow landsliding. A series of meteorological events that triggered soil slips in northern Italy were studied to define rainfall thresholds and to evaluate a possible regionalization. Soil properties, triggering rainfall, and local lithological and morphometrical settings of different sites were used as input to an infiltration model. The approach allows the recognition of several triggering conditions in the Piedmont, Pre-Alpine and Alpine regions. This suggests the need for different rainfall thresholds with respect to those derived with other methods. Intensity versus rainfall duration relationships become particularly important when related to soil permeability and thickness, and demonstrate the role of antecedent precipitation. Events with exceptional water discharge from obstructed road culverts reveal the role played by anthropic structures in triggering such phenomena. Different approaches to slope stability analysis are shown, taking into account bedrock lithology, topography, seepage, and local saturation conditions. Received: 23 October 1997 · Accepted: 25 June 1997  相似文献   

坡面溅蚀发生过程及其与坡度关系的模拟研究   总被引：11，自引：0，他引：11  

张科利  细山田健 《地理科学》1998,18(6):561-566

通过人工模拟降雨试验,分别观测降雨过程中不同方向上溅蚀强度的变化,根据各影响因子间相互消长及相互制约的关系特点,分析了雨滴溅蚀发生的过程特征及其变化原因,从溅蚀过程的变化特点及溅蚀强度的变化规律比较,定量地探讨了坡度对雨滴击溅侵蚀的影响作用,得出了溅蚀强度与坡度因子之间的关系方程。  相似文献   

Shallow landslides in deeply weathered slates of the Sierra de Collcerola (Catalonian Coastal Range, Spain)     

Domenico Calcaterra  Jos A. Gili  Roberto Iovinelli 《Engineering Geology》1998,50(3-4):283-298

Stability conditions in an area located NW of Barcelona (Spain) are discussed. Here, several mass movements were observed, mainly affecting weathered Paleozoic slates. Many of these failures involved slopes cut along recent infrastructures: debris flows, wedge and plane failures, generally surficial, occurred more frequently. After a detailed geological and geomorphologic survey, geomechanic characterization was carried out, according to RMR and SMR classifications. This rating gave a prediction of slope behaviour, in fairly good agreement with the real observed one.

Stability numerical analysis was carried out for the main cut slopes, based upon the Limit Equilibrium Method. First of all, the deterministic factor of safety was computed using the mean values of parameters. After that, a simulation technique based upon the Monte Carlo Method was applied in order to obtain factor of safety distributions. The probability of failure was estimated as P(F<1).

Finally, results from deterministic and probabilistic approaches were compared. The effectiveness of different possible remedial measures was highlighted by means of a sensitivity analysis, which showed that the more important parameters in the study area are the geometrical ones (height, slope and failure plane angles). The final technical solutions adopted are briefly outlined.  相似文献