Bearing Capacity of Embedded Strip Footings on Cohesionless Soil Under Vertical and Horizontal Loads

In the last decades a few attention was given to the evaluation of the bearing capacity of embedded footing under inclined loads on a frictional soil. This paper focuses on a numerical study using the finite-difference code Fast Lagrangian Analysis of Continua (FLAC), to evaluate the bearing capacity of embedded strip footing on a frictional soil. The soil is modeled by an elasto-plastic model with a Mohr–Coulomb yield criterion and associative flow rule; the effect of non-associativity of the soil on the bearing capacity is also investigated. The effect of the embedment is estimated though a depth factor, defined as a ratio of the bearing capacity of a strip footing at a depth D to that of a strip footing at the ground surface. The inclination effect is estimated by inclination factors, defined as the ratio of the limit vertical load for a footing under inclined loading to that of the vertically loaded footing. Both swipe and probe analyses were carried out to identify the vertical force–horizontal force (V–H) failure envelope. The results have been compared with those available in the literature.     

Geology, mineralogy, and chemistry of the M’zila bentonitic clay deposit (Mostaganem, NW Algeria)

Bentonitic clay deposit of M’zila locates in the North border of the upstream portion of the Chélif basin “Bas Chélif” down to 35 km NE of Mostaganem. It consists of 14 layers (most recent) 1 to 14 (oldest) forming the North and South flanks of an E–W Syncline. These layers are enclosed in the median blue marls formation of the Upper Miocene of the “Bas Chélif” basin lying unconformably on the ante thrust sheet sandstone formation. This median member contains metric cinerites thick continuous levels and could beings originally bentonitic clay region of M’zila. The cinerites are the product of explosive type in the volcanic eruption, usually deposited in the marine environment. They are formed by a more or less rich feldspar and biotite volcanic glass dust. Bentonitic clay layers have average thicknesses vary between 2 and 6 m. They are distributed by centimeter to decimeter levels of soft sandstone, sandy, and rich black mica. Sandstone is greywacke clay and carbonated cemented, matrix consisting of quartz, feldspars, biotite as major minerals, zircon, and glauconite as accessory minerals. They deposited in a marine, reduced, and confined environment. Mineralogical composition of bentonitic clay region of M’zila is as follows: (1) Clay minerals are represented by the montmorillonite with a small amount of kaolinite. (2) Non-clay minerals are composed mainly of quartz, albite, biotite, calcite, heulandite, chlorite, dolomite, and gypsum. Infrared spectroscopy shows that bentonitic clay has highlighted the presence of the disorderly a high temperature silica tridymite. Geochemistry of the major elements of M’zila bentonitic clay shows high a percentage of SiO₂ and Al₂O₃. Chemical analysis shows that the 10, 12, 14 B 7, 4 A, and 4 clay layers are ferric clay; 11 and 3 layers are magnesian clay. Particle size analysis by sedimentation shows bentonitic clays are accrued mainly clay fractions to silt. Bentonitic clay deposit of M’zila has probably volcanic origin and deposited in a marine, reduced, and confined environment.     

Sediment mobilization study on Cretaceous,Tertiary and Quaternary lithological formations of an external Rif catchment,Morocco

ABSTRACT

Soil erosion is a serious ecological problem in Mediterranean areas. The IntErO model based on the erosion potential method (EPM) and the modified universal soil loss equation (MUSLE) have been used to assess soil erosion in several basins. This study aimed to assess and evaluate the effectiveness of these methods for evaluating sediment production and deposition rates in the Arbaa Ayacha basin, Morocco, in order to estimate sediment fluxes on a catchment scale. Our findings suggest that the basin is strongly exposed to erosion owing to geological formations, slope and land use, with average losses of about 28.4 t ha^?1 year^?1. Erosion processes were evaluated at the erosion production (Eocene marly formations) and sedimentation zones (Quaternary terraces). The results of these models may be useful to address soil and water management in this region and to assess the impact of a river dam that will be built in the basin.     

Identification and mapping of clay minerals in the region of Djebel Meni (Northwestern Algeria) using hyperspectral imaging,EO-1 Hyperion sensor

Applied in Djebel Meni (Northwestern of Algeria), this research highlights the results obtained from the supervised classification using the Spectral Angle Mapper (SAM) algorithm, through introducing the spectral signatures of illite, kaolinite, and montmorillonite, via Jet Propulsion Laboratory (JPL) spectral library. These results were compared to the ones of the SAM classification, which use spectral signatures obtained by the Sequential Maximum Angle Convex Cone (SMACC) endmembers extraction algorithm. This implies the ability to detect and identify any object present on the Earth’s surface, whether its nature is mineral, vegetal, or human made, from hyperspectral imaging. By extracting the spectral signatures with the SMACC algorithm and matching them to the current signatures of JPL spectral library, comparing spectral signatures with another is not an easy task. Indeed, for a better comparison and a more appropriate interpretation in the use of the SAM classification, the results obtained were very relatively convincing because, regarding very strong similarities. It appears also that the signatures extracted with SMACC occupy the same areas as those of the JPL spectral library. This method of detection and identification of any present object on the Earth’s surface is rather conclusive.     

Modelling background seismicity components identified by nearest neighbour and stochastic declustering approaches: the case of Northeastern Italy

Stochastic Environmental Research and Risk Assessment - An adequate characterization of the temporal features of background seismicity, namely after removal of temporally and spatially clustered...     

The vein-type barite mineralization of the Draïssa ore field,Ougarta; SW- Algeria: mineralogy,trace elements and halogens

The Draïssa barite vein system in the Ougarta district is located in southwestern Algeria. It is the principal mineral deposit of economic interest of the area. The mineralization is hosted by Cambrian sedimentary rocks that unconformably overlie Precambrian formations. The mineralized structures consist mostly of barite and quartz with minor sulfide minerals and trend dominantly NE-SW, NW-SE, and E-W. Siliceous alteration zones are associated with the vein system. Samples of barite ore are characterized by low total REE contents ranging from 9 to 50 ppm and positive Eu (2–2.15 ppm) and Y (1.2–11.1 ppm) anomalies, indicating hydrothermal activity during mineralization. Halogen data of the barite show that the Cl/Br molar ratio is 189:571 and the Na/Br ratio is 34:376, indicating that the sulfur was derived from seawater. The Ba-enrichment trend in the volcanic rocks of Draïssa is interpreted as possible probable source of the Ba (424–3039 ppm Ba). It appears that the barite-quartz deposits were formed in two stages. Endogenous fluids deposited the primary vein materials, consisting of quartz associated with copper sulfides. Exogenous fluids (cold seawater) became heated during ascendant fluid movement. Mineralization was governed by convective motions and the barite and galena fillings were deposited in openings created by normal faulting.     

A mixed model for earthquake interevent times

A mixed model is proposed to fit earthquake interevent time distribution. In this model, the whole distribution is constructed by mixing the distribution of clustered seismicity, with a suitable distribution of background seismicity. Namely, the fit is tested assuming a clustered seismicity component modeled by a non-homogeneous Poisson process and a background component modeled using different hypothetical models (exponential, gamma and Weibull). For southern California, Japan, and Turkey, the best fit is found when a Weibull distribution is implemented as a model for background seismicity. Our study uses earthquake random sampling method we introduced recently. It is performed here to account for space–time clustering of earthquakes at different distances from a given source and to increase the number of samples used to estimate earthquake interevent time distribution and its power law scaling. For Japan, the contribution of clustered pairs of events to the whole distribution is analyzed for different magnitude cutoffs, m _c, and different time periods. The results show that power laws are mainly produced by the dominance of correlated pairs at small and long time ranges. In particular, both power laws, observed at short and long time ranges, can be attributed to time–space clustering revealed by the standard Gardner and Knopoff’s declustering windows.