Investigation of deposits for traditional extraction activities (metals and coal) has generally been based on determining grade, or content, of the required material. In order to apply the grade concept to an ornamental rock such as slate, it is first necessary to define the variables that determine both the geotechnical recovery rate for the rock mass — which conditions the size of the extracted blocks – and the aesthetic features of the slate — which define the quality of the slabs as potential roofing material.
For this research, geotechnical and aesthetic data for a slate deposit were collected from 16 continuous core borehole samples. A fuzzy expert system was then developed using this data, defining the rock mass recovery rate and slab quality in accordance with the criteria of a slate expert, producing as a final output a zonation of the deposit in terms of top quality slate, medium quality slate or waste.
A mathematical model based on fuzzy logic was chosen due to the fact that the boundaries between different quality groups in a deposit are not clearly distinguished. Moreover, quality also depends on a company's infrastructures for transformation of the blocks, and also on its commercial strategies. 相似文献
A decision support system (DSS) has been developed to assist expert and non-expert users in the evaluation and selection of
eco-engineering strategies for slope protection. This DSS combines a qualitative hazard assessment of erosion and mass movements
with a detailed catalogue of eco-engineering strategies for slope protection of which the suitability is evaluated in relation
to the data entered. The slope decision support system (SDSS) is a knowledge based DSS in which knowledge is stored in frames
containing rules that can evaluate the available information for a project, stored as project specific information (PSI) in
a data file. The advantages of such a system are that it accepts incomplete information and that the qualitative nature of
the information does not instil the user with a sense of unjustified exactitude. By its multidisciplinary and progressive
nature, the DSS will be of value during the initial stages of an eco-engineering project when data collection and the potential
of different eco-engineering strategies are considered. The accent of the output of the DSS is on the application of eco-engineering
strategies for slope protection as an environmentally-friendly solution aiding sustainable development. For its acceptance
within the engineering community, the DSS needs to prove its predictive capacity. Therefore, its performance has been benchmarked
against successful and unsuccessful cases of slope stabilisation using eco-engineering. The target audience and the areas
of application of this DSS are reviewed and the strategies for further development in this area suggested. 相似文献
Along a 2 km NW-SE transect along the energy gradient of an intertidal sand body of the back-barrier tidal flats of Spiekeroog island (German Wadden Sea, southern North Sea), three sets of closely spaced surface sediment samples were taken at different times to investigate whether the effects of progressive size sorting could be identified in the textural parameters and size-frequency curves of the sediments. Grain-sizes analyses were carried out with a high-resolution settling tube having an internal resolution of 1/50-psi intervals. The settling velocity data were subsequently transformed numerically into equivalent settling diameters on the basis of a quartz sphere standard. At this high resolution, it was possible to visualize subtle changes in textural parameters which would not have been resolved by standard 0.25-phi sieve analyses. The first two sample sets of 1992 and 1994 show similar trends of progressive fining in the sediment, combined with a slight decrease in skewness and sorting in the direction of decreasing energy. Ten years later, in 2003, the sediments were slightly coarser but still reflected the hydrodynamic energy gradient by a distinct fining trend along the transect. However, in contrast to the former data sets, the skewness values now remained constant, whereas the sorting values revealed the existence of two overlapping hydrodynamic energy regimes on the tidal flat. The better sorting in the coarser size fractions and the general coarsening trend in the central part of the tidal flat are interpreted to reflect an increase in the hydrodynamic energy level since the first two sample sets were collected. This observation suggests that some of the finer particles in the grain-size spectrum on the tidal flat were winnowed out by wave action without, however, completely obliterating the former trend. This interpretation is supported by an increase in the frequency and duration of strong winds as recorded by the national weather bureau since the early 1990s. The results of the study demonstrate that the intertidal sediments of the Wadden Sea respond rapidly and sensitively to gradual changes in the hydrodynamic energy regime. 相似文献
The effects of climate change on the groundwater systems in the Grote-Nete catchment, Belgium, covering an area of 525 km2, is modeled using wet (greenhouse), cold or NATCC (North Atlantic Thermohaline Circulation Change) and dry climate scenarios. Low, central and high estimates of temperature changes are adopted for wet scenarios. Seasonal and annual water balance components including groundwater recharge are simulated using the WetSpass model, while mean annual groundwater elevations and discharge are simulated with a steady-state MODFLOW groundwater model. WetSpass results for the wet scenarios show that wet winters and drier summers are expected relative to the present situation. MODFLOW results for wet high scenario show groundwater levels increase by as much as 79 cm, which could affect the distribution and species richness of meadows. Results obtained for cold scenarios depict drier winters and wetter summers relative to the present. The dry scenarios predict dry conditions for the whole year. There is no recharge during the summer, which is mainly attributed to high evapotranspiration rates by forests and low precipitation. Average annual groundwater levels drop by 0.5 m, with maximum of 3.1 m on the eastern part of the Campine Plateau. This could endanger aquatic ecosystem, shrubs, and crop production. 相似文献
The work is dedicated to most important abiotic processes of the Early Precambrian, effect of which is recorded in continental crust, and to complementary processes in subcontinental mantle. We intend to figure out when a certain process was triggered first in the past and what indications suggest its further activity, evolution and possible cessation in subsequent geological history. Considerations are based on described natural objects characterizing particular geological events and enabling the cause-and-effect interpretation in order to understand different viewpoints known from publications. Considered in the work are the early Precambrian greenstone belts and ophiolites, island-arc systems and ecologites, magmatism unconnected with subduction zones (rifting-related, plateau basalts, dykes, kimberlites) and anorthosites representing a group of heterochronous intrusions of complicated genesis. Main considerations are premised with a brief review of the earliest geodynamic phenomena associated with meteorite impacts by termination of the planetary accretion. 相似文献
A recent revolution in the study of nonlinear dynamical systems in the physical sciences has shown the worth of regarding systems as dissipative. The nature of dissipative systems in equations, bifurcations, and fluctuations. Some speculations are then made concerning the implications of dissipative system theory for geomorphology. It is suggested that geomorphological systems containing bifurcations will have both deterministic (universal and necessary) and probabilistic (historical happenstance) elements; they will have more than one solution (configuration) and this fact calls into question notions of process domains leading to the development of characteristic forms; they will possess varying degrees of susceptibility to change induced by fluctuations; and they will respond differently to local, regional, and global fluctuations. 相似文献