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Abdelkader Ouali Mehadji Serge Elmi Patrick Rachebœuf Larbi Mekahli 《Comptes Rendus Geoscience》2004,336(14):1283-1292
In the Saoura, the brachiopod shell beds, so-called niveau coralligène, correspond to a major shell deposit dated to the Late Emsian. Brachiopods and crinoids dominate the benthic assemblage that contains also corals, bryozoans, trilobites, goniatites, and orthocones. This major level has a large geographic distribution and it is characterized by a wide brachiopod diversity due to time-averaging, taphonomic feedback and alternate bottom conditions changing from soft to shelly and firm. This kind of brachiopod association is linked to a transgressive onlap system. At regional extent, we can correlate this major shell bed to similar shell deposits from the Ahnet-Mouydir, Tindouf, and Zemmour areas. It indicates an important transgressive event underlined by change in the sedimentation from detritic deposits to carbonate sediments. To cite this article: A. Ouali Mehadji et al., C. R. Geoscience 336 (2004). 相似文献
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Groundwater of the Tafilalet oasis system (TOS) is an important water resource in the lower Ziz and Rheris valleys of arid southeastern Morocco. The unconfined aquifer is exploited for domestic consumption and irrigation. A groundwater flow model was developed to assess the impact of climatic variations and development, including the construction of hydraulic structures, on the hydrodynamic behavior of the aquifer. Numerical simulations were performed by implementing a spatial database within a geographic information system and using the Arc Hydro Groundwater tool with the code MODFLOW-2000. The results of steady-state and transient simulations between 1960 and 2011 show that the water table is at equilibrium between recharge, which is mainly by surface-water infiltration, and discharge by evapotranspiration. After the commissioning of the Hassan Addakhil dam in 1971, hydraulic heads became more sensitive to annual variations than to seasonal variations. Heads are also influenced by recurrent droughts and the highest water-level changes are recorded in irrigated areas. The model provides a way of managing groundwater resources in the TOS. It can be used as a tool to predict the impact of different management plans for the protection of groundwater against overexploitation and deterioration of water quality. 相似文献
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Brahim Abdelkader Ahmed Arab Marwan Sadek Isam Shahrour 《Geotechnical and Geological Engineering》2018,36(4):2077-2085
This paper presents the results of triaxial tests conducted for the investigation of the influence of geotextile on both the stress–strain and volumetric change behavior of reinforced sands. Tests were carried out on loose sand. The experimental program includes drained compression tests on samples reinforced with different values of both geotextile layers (1 ≤ Ng ≤ 3) and confining pressure (\(\upsigma_{\text{c}}^{\prime }\)) varying from 50 to 200 kPa. Tests show that the contribution of geotextile is negligible until an axial strain threshold that range between 2.5% for a confining pressure of 50 kPa to lower than 1% for 100 and 200 kPa confining pressure. At higher values of εa, geotextile induces a quasi-linear increase in the stress deviator (q) and volume contraction in the reinforced sand. Tests show a negligible influence of the number of geotextile layers (Ng) on the contribution of geotextile to both stress–strain and volumetric change, when normalized with Ng. Tests also show that the contribution of geotextile to the stress–strain mobilization augments with the increase in the confining pressure, while its contribution to the volume contraction decreases with the increase in the confining pressure. The reinforced soil becomes contracting in the case of 2 and 3 geotextile layers. 相似文献
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A. El Ouali J. Mudry J. Mania P. Chauve N. Elyamine M. Marzouk 《Environmental Geology》1999,38(2):171-176
The Errachidia basin is composed of three superposed aquifers (Senonian, Turonian limestones and Infracenomanian). The Liassic
limestone of the upper Atlas borders the northern part of the basin. The piezometric map of the Turonian aquifer displays
a north-south flow, with an inflow area from the Atlas. This recharge hypothesis is demontrated by a discriminant analysis
performed on chemical data: the majority of the spots are of sodium choride and hydrogenocarbonate types, while several boreholes
are assigned to a calcium hydrogenocarbonate type Jurassic component.
18O measurements, using the Atlasic gradient δ18O=–4.18–0.0027 x elevation to estimate the recharge areas, confirm that the recharge area is the basin itself (<1100 m) on
the Turonian outcrops, while in the confined part, the Turonian is recharged higher than 1400 m (corresponding to the Atlas).
This contribution ranges from 56 to 85%, according to the situation versus the piezometric inflow area. The remainder represents
infiltration and vertical leakage from the Senonian layers. 相似文献
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Azeddine Guidoum Abdelmalek Nemouchi Abdelkader Hamlat 《Arabian Journal of Geosciences》2014,7(10):3925-3943
Aurès region remains one of the most exposed areas to water erosion phenomenon in Algeria, because of the strong climatic aggressiveness, the rugged relief, the predominance of sensitive land, and a vegetative cover that does not play its protective role. This article is a part of studies performed to protect agricultural and water infrastructure in this region. The main objective of this study is the cartographic modeling of an erosion hazard at the Oued Chemoura watershed, representative of the Aurès. The modeling approach uses a geographic information system and incorporates the following six factors controlling erosion: slope, friability of substrate, erodibility of soils, land cover, rainfall erosivity, and support practices. Result shows a synthetic map of the soil erosion hazard which locates the most threatened areas and priorities for possible planning interventions. A statistical study on the relationship solid–liquid flow was developed. Measurements conducted at the station of Chemoura, over the period 1969–1994, were exploited for this purpose. The results show a high specific degradation varying between 50 and 360 tons km?2 season?1. 相似文献
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Mahallem Abderrahmane Roudane Mohamed Krimi Abdelkader Gouri Sid Ahmed 《Landslides》2022,19(5):1249-1263
Landslides - This work aims to develop a Weakly Compressible Smoothed Particle Hydrodynamics (WCSPH) in-house code for modelling landslide–water interaction problems. While we consider the... 相似文献
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Aicha Berkane Mezhoud Samy Tayeb Bouzid Toufik Karech Abdelkader Noui 《Geotechnical and Geological Engineering》2022,40(4):2307-2318
Geotechnical and Geological Engineering - When designing tunnels, it is advisable to pre-estimate several tunnel parameters such as the depth (cover), the lining thickness, and the shape of the... 相似文献
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Bouri Djamel Eddine Brahimi Abdelkader Krim Abdallah Arab Ahmed Najser Jan Mašín David 《Geotechnical and Geological Engineering》2022,40(4):1675-1692
Geotechnical and Geological Engineering - This paper presents a study on Chlef sand to examine the effect of fines content (Fc), relative density (RD) and initial conditions on the compressibility... 相似文献
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Khalid Qahman Abdelkader Larabi Driss Ouazar Ahmed Naji Alexander H. -D. Cheng 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(2):99-110
Four examples are investigated for the optimal and sustainable extraction of groundwater from a coastal aquifer under the threat of seawater intrusion. The objectives and constraints of these management scenarios include maximizing the total volume of water pumped, maximizing the profit of selling water, minimizing the operational and water treatment costs, minimizing the salt concentration of the pumped water, and controlling the drawdown limits. The physical model is based on the density-dependent advective-dispersive solute transport model. Genetic algorithm is used as the optimization tool. The models are tested on a hypothetical confined aquifer with four pumping wells located at various depths. These solutions establish the feasibility of simulating various management scenarios under complex three-dimensional flow and transport processes in coastal aquifers for the optimal and sustainable use of groundwater. 相似文献