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Mohamed Sabri Arfaoui Radhouane Khouni Soufiene Dridi Fouad Zargouni 《Arabian Journal of Geosciences》2018,11(5):95
The Bou Arada-El Fahs troughs system is a particularly E-W trending collapsed structure with the manifestation of normal-to-strike-slip faults. A combined multi-source and multi-scalar structural and geophysical investigation provides important insights on the geometry and the kinematics evolution of trough systems in the Atlas of Tunisia. New data, as well as a reappraisal of available data show that the studied troughs system is established during three main successive events: the Oligocene-Miocene, the Tortonian, and the Plio-Quaternary events. The goal of this paper is to present the structural evolution of the study area, on a pre-structured substratum. The structural evolution progressed from an extensional event, manifested by the formation of grabens, passing by an episode of reactivation of faults related troughs in strike-slip motion during the Atlas compression accompanied by an en-échelon folding in foot wall and hanging wall. These results acquired and presented in the following order: We will initially present the geological context by integrating and correlating the lithostratigraphic data. We continue by examining the geometry and kinematics of structure-related troughs via the detailed geological mapping, the interpretation of available 2D seismic data, and the interpretation of processed fault slip data. This integrated geological and geophysical study allows a better understanding of the BETS, and makes it possible to propose a new geometrical and kinetic model of the establishment of trough structure in the Tunisian Atlas. 相似文献
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The paper examines the mechanics and physics of granular material responses at the macroscopic and microscopic levels during both monotonic and cyclic loadings. A numerical analysis referring to a long retaining wall is conducted using a two-dimensional discrete element model representing a granular system with a free top surface. On one of the lateral boundaries referring to the retaining wall, both active and passive loadings were applied monotonically as well as cyclically. First, the development of sheared zones and classic failure wedges resulting from active and passive monotonic displacements are discussed with respect to Rankine’s and Roscoe’s solution angles. Then, a series of loading cycles were performed using slow small-amplitude displacements at different stress states chosen before the occurrence of failure along the passive monotonic stress response curve. Particular interest is focused on the ultimate asymptotic cyclic response of the granular system, the occurrence of a high-mobility (convective) zone and a detailed macroscopic and microscopic analysis. Finally, major kinematical features that are displayed during cyclic loading from different starting stresses to eventually reach the same asymptotic state were elucidated through particle vortex-like flux formations, including contact rotations. The change in material stiffness was also investigated based on the evolution of strong and weak contact networks, together with the analysis of fabric anisotropy within the entire domain, including the high-mobility zone considered separately.
相似文献3.
It has been established that the second‐order work criterion is a general necessary condition for all instabilities by divergence in rate‐independent granular materials. The relation between the values of discrete second‐order work at the intergranular contact point level and its global macroscopic value is recalled at the beginning of this paper. Then, the basic purpose of the paper is tackled by an analysis of the main features of second‐order work criterion in relation with the granular microstructure. For that, it is considered a novel micromechanical model (the so‐called ‘H‐microdirectional model’), which has the property to involve three scales: grain scale, mesoscale with a specific granular configuration and continuum mechanics macroscale. Eventually, these exhibited features (a bifurcation stress domain and some instability cones) are qualitatively compared with the ones provided by direct numerical simulations issued from a discrete element model. The ultimate goal is to analyse what happens at the granular scale, when the macrosecond‐order work is vanishing at the macrolevel. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Radhouane Khouni Mohamed Sabri Arfaoui Soufiane Dridi Fouad Zargouni 《Arabian Journal of Geosciences》2018,11(4):68
During the Mesozoic and Cenozoic rifting, the Pelagian Sea recorded the consequences of the African and European plate’s rapprochement. The interpretation of surface and subsurface data that is the 2D seismic reflection and petroleum well data show new ideas on the geodynamic evolution and halokinesis of the Jeffara basin during the Mesozoic and Cenozoic period. Seismic lines interpretations of the subsurface mainly reveal normal syn-sedimentary NW-SE faulting and where the Jeffara fault seems to be the major play. This syn-sedimentary faulting induced horst and graben structures materialized by major sedimentary sequences thicknesses as well as depths variations on the seismic profiles from the Jeffara fault zone overall towards the East of Jeffara basin. After the Hercynian event of the Permian - Carboniferous age, a general extension took place, which gave rise to the Tethyan opening. This extension has favored the individualization of the Jeffara basin in the South East of Tunisia, characterized by a structuring in Horst and Graben with a Permian carbonate subsidence. During the Triassic - Middle Jurassic period, the Jeffara basin is marked by a pronounced subsidence of essentially evaporate sedimentation accompanied by the birth of normal syn-sedimentary NW-SE faults following an NE-SW extension. This subsidence continuing during the Upper Jurassic period, the accentuation of which is towards the NE of the study zone at the Jerba and El Bibane sub-basin with a dominance of bioclastic limestone and dolomites sedimentation in the same extensive NE-SW direction, during this period, the Jeffara basin was characterized by a beginning of salt activity indicated by the appearance of salt nuclei at the base of the preexisting NW-SE normal faults. During the Lower Cretaceous, we are witnessing an individualization of salt complexes in the SE of the study area at Rass Ajil sub-basin, where this reactive diapirism has produced high zones and erosions in the crest above the salt bodies. During the mid Cretaceous period, the Zebbag formation, hatched by the Gattar carbonate bar, recorded a subsidence inversion phenomenon between the three sub-basins Jerba, El Bibane and Rass Ajil sub-basin, and showed the change of movement of the African plate relative to the European plate related to the opening of the North Atlantic and the beginning of the drift towards the North of Africa. This phenomenon is concretized towards the Upper Cretaceous, where we witness a strong subsidence towards the southeastern part of the study area at Rass Ajil sub-basin with sandstone, marl and clay sedimentation under a regional extensive regime and the individualization of high zones at Jerba sub-basin. The salt movements present an active aspect by piercing their cover and inducing rim synclines in the surroundings. The Cenozoic period is characterized by a strong subsidence of sandstone, clays and carbonates along the Jeffara basin, the salt activity shows a passive aspect at the beginning of this period which slows down and eventually stopped at the late Miocene period, thus indicating the probable exhaustion of the source of the salt material. 相似文献
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Abstract Reservoir silting is one of the principal problems affecting the performance of dams in Algeria from the standpoint of reservoir capacity for storage. Foum El Kherza Reservoir (also known as Foum El Gherza), near Biskra Town, Algeria, is subject to dredging operations with the intent of recovering 70% of its initial storage capacity of 47 hm3 (million cubic metres). The forecasting of sediment volume trapped in the reservoir is essential to plan the future use of this resource and to sustain irrigation for the palm groves characteristic of the region. However, there are currently no sediment data, nor a sediment rating curve, for predicting sediment inflow based on hydrological data. This paper describes the optimization of a cumulative trapped sediment curve for Foum El Kherza Reservoir based on 44 years of daily inflows, by using a spreadsheet optimization tool, Microsoft Excel® Solver to calibrate the cumulative sediment load against the cumulative sediment inflow as documented by eight bathymetric surveys since the dam construction. Editor D. Koutsoyiannis; Associate editor A. Montanari Citation Tebbi, F.Z., Dridi, H., and Morris, G.L., 2012. Optimization of cumulative trapped sediment curve for an arid zone reservoir: Foum El Kherza (Biskra, Algeria). Hydrological Sciences Journal, 57 (7), 1368–1377. 相似文献
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The variation of the natural radionuclide concentrations depends on the chemical composition of each site. In this work, two thermal springs in the east of Algeria have been chosen to assess the activity concentration of natural radionuclide, mainly the three natural radioactive series 238U, 235U and 232Th, and 40K. The high-resolution gamma ray spectroscopy was used to determine these concentrations. In these water samples, 235U, 234Th, 210Pb, 226Ra radionuclides are less than the minimum detectable activity. The activity of 238U is dominant. The 238U activity was determined by taking the mean activity of two separate photo-peaks of daughter nuclides 214Pb at 351.92 (37.2%) keV and 214Bi at 609.31 (45%) keV. The measured activity concentrations of 238U in water samples obtained from the concentrations of 214Bi and 214Pb ranged from 0.56 ± 0.20 to 1.13 ± 0.20 Bq/L. The annual effective dose value due to the ingestion of the measured radionuclide 238U in 1 L of water, for an adult, ranged from 9.20 to 18.56 µSv. 相似文献
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The spatial and temporal variation of moisture distribution, overall water balance and quantity of infiltrated water in the vadose zone of the Sidi Bouzid Plain (Tunisia) during successive flooding events is quantified in this study. The variation in water content in response to environmental factors such as evaporation and water root uptake is also highlighted. One-dimensional flow simulations in the deep vadose zone were conducted at three spreading perimeters located near Wadi El Fekka. The hydraulic boundary conditions of a time-dependent water blade applied to the soil surface were determined from measured flood hydrographs. For the chosen wet year, the successive flooding events contributed to a significant artificial recharge of the natural groundwater. Although the soil hydraulic parameters did not vary strongly in space, flow simulations showed significant differences in the overall water balance of approximately 9–16% for the various spreading perimeters. 相似文献
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Channels of synthesis forty years on: integrated analysis of spatial economic systems 总被引：3，自引：1，他引：2
Geoffrey J.D.?HewingsEmail author Suahasil?Nazara Chokri?Dridi 《Journal of Geographical Systems》2004,6(1):7-25
Isards vision of integrated modeling that was laid out in the 1960s book Methods of Regional Science provided a road map for the development of more sophisticated analysis of spatial economic systems. Some forty years later, we look back at this vision and trace developments in a sample of three areas – demographic-econometric integrated modeling, spatial interaction modeling, and environmental-economic modeling. Attention will be focused on methodological advances and their motivation by new developments in theory as well as innovations in the applications of these models to address new policy challenges. Underlying the discussion will be an evaluation of the way in which spatial issues have been addressed, ranging from concerns with regionalization to issues of spillovers and spatial correlation. 相似文献
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Contribution of Landsat 8 data for the estimation of land surface temperature in Batna city,Eastern Algeria 总被引：1，自引：0，他引：1
In this study, we presented a mono-window (MW) algorithm for land surface temperature retrieval from Landsat 8 TIRS. MW needs spectral radiance and emissivity of thermal infrared bands as input for deriving LST. The spectral radiance was estimated using band 10, and the surface emissivity value was derived with the help of NDVI and vegetation proportion parameters for which OLI bands 5 and 4 were used. The results in comparison with MODIS (MOD11A1) products indicated that the proposed algorithm is capable of retrieving accurate LST values, with a correlation coefficient of 0.850. The industrial area, public facilities and military area show higher surface temperature (more than 37 °C) in comparison with adjoining areas, while the green spaces in urban areas (34 °C) and forests (29 °C) were the cooler part of the city. These successful results obtained in the study could be used as an efficient method for the environmental impact assessment. 相似文献
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Caterina Casagranda Mohamed Sadok Dridi Charles Franois Boudouresque 《Estuarine, Coastal and Shelf Science》2006,66(3-4):437-446
Abundance, population structure and production of the macro-invertebrates belonging to the functional feeding group of the shredders were studied in the Ichkeul wetland, northern Tunisia, from July 1993 to April 1994. Mean above-ground macrophyte biomass was at a maximum in September followed by a complete breakdown of the Potamogeton pectinatus L. meadow from October onward due to high salinity following an exceptionally dry winter. Only the meadow of Ruppia cirrhosa (Petagna) Grande at Tinja remained in place. Abundance of Gammarus aequicauda (Martynov 1931), Idotea chelipes (Pallas 1766) and Sphaeroma hookeri Leach 1814 was significantly related to the R. cirrhosa biomass. Gammarus aequicauda presented two recruitment periods in spring and autumn, and S. hookeri a third one in winter. The population of I. chelipes was renewed during winter by continued reproduction without any spring generation. Recruitment of all three species was not very successful during the study period. Life span of all three species was between 12 and 15 months. Despite their relatively low biomass and production rate, the shredders have a key function in processing macrophyte matter to different trophic levels through fragmentation and accelerating the decomposition of macrophyte biomass accumulated at the end of the growth season in the Ichkeul lagoon. 相似文献
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