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11.
Mohamed Ashour Gary M. Norris Sherif Elfass Ashraf Z. Al-Hamdan 《Computers and Geotechnics》2010,37(7-8):858-866
This paper presents a procedure to assess the mobilized pile side and tip resistance versus pile head and tip settlement under axial load in clay soil. The load transfer (t–z) curve is evaluated at any point on the loaded pile based on the combined pile tip/side resistance–displacement mechanisms along the length of the pile. Unlike current methods that assume the pile settlements as a percentage of the pile/shaft diameter, the presented technique determines the side and tip resistance of the pile and the associated pile settlement under existing load based on the current stress/strain level in the surrounding soil up to failure (excessive settlement). The technique employs the concepts of the elastic theory and Ramberg–Osgood characterization of the stress–strain behavior of the clay soil. Case studies are also presented to exhibit the capabilities of the proposed procedure. The good agreement between measured and calculated load transfer curves along the pile and pile tip resistance versus pile head, side, and tip displacements shows the consistency of the proposed procedure. A computer code is developed to employ the presented technique. 相似文献
12.
Sherif Kharbish 《Chemie der Erde / Geochemistry》2010,70(3):257-266
Wadi El-Markh gabbro–diorite complex is composed of pyroxene hornblende gabbros, hornblende gabbros, diorites and quartz diorites. According to their bulk rock geochemistry and mineral chemistry, the gabbroic and dioritic rocks represent fractionates along a single line of descent and crystallized from a calc-alkaline mafic magma. When compared to the primitive mantle, all members of the gabbroic–dioritic rock suite are enriched in the large ion lithophile elements relative to the high field strength elements and display distinctive negative Nb and P2O5 anomalies. This signals an arc setting. Fractionation modeling involving the major elements reveals that the hornblende gabbros were generated from the parent pyroxene hornblende gabbros by 61.86% fractional crystallization. The diorites were produced from the hornblende gabbros by fractional crystallization with a 58.97% residual liquid, whereas the quartz diorites were formed from the diorites by 26.58% fractional crystallization. According to geothermobarometry based on amphibole mineral chemistry, the most primitive pyroxene hornblende gabbros crystallized at ～830 °C/～5 kbar. The crystallization conditions of the quartz diorites were estimated at ～570 °C/～2 kbar. In consequence the Wadi El-Markh gabbro–diorite complex represents a single magmatic suite of which fractionates crystallized in progressively shallower levels of an arc crust. 相似文献
13.
An earthquake of local magnitude 5.3 (duration magnitudeM
d
) on the Richter Scale occurred at Dahshour, 18 km south of Cairo, Egypt, on Monday, 12 October 1992 at 3:09 pm (local time). Numerous aftershocks followed the main event during the following weeks with magnitude up to 4.3. The earthquake occurred in an area that has had no recent seismic activity, and affected many cities in Egypt. Many buildings and monuments were severely damaged or collapsed. Modern concrete skeletal structures suffered minor nonstructural damage. Earthquake physical damage was estimated at about one billion U.S. Dollars. The severity of the damage was mainly due to poor construction materials and detailing, aging, inferior workmanship, and inadequate maintenance. Egypt was generally considered to be an area of moderate seismic activity. In 1989, earthquake provisions were first introduced in the Egyptian Code of Practice for Reinforced Concrete Structures only. The earthquake clearly showed the urgent need for an assessment and rehabilitation program to mitigate seismic risk hazard in existing structures. In addition, future development planning, and earthquake preparedness strategies should implement lessons learned from the event. In this paper, an overview discussion about the observations from the 12 October earthquake is presented. 相似文献
14.
Geoelectrical and hydrogeochemical studies for delineating seawater intrusion in the outlet of Wadi Ham, UAE 总被引：2，自引：0，他引：2
M. Sherif A. El Mahmoudi H. Garamoon A. Kacimov S. Akram A. Ebraheem A. Shetty 《Environmental Geology》2006,49(4):536-551
The Quaternary aquifer of Wadi Ham, UAE has been overexploited during the last two decades to meet the increasing water demands.
As a result, the dynamic balance between freshwater and seawater has been disturbed and the quality of the groundwater has
deteriorated. In this paper, a 2D earth resistivity survey was conducted in Wadi Ham in the area between Fujairah and Kalba
to delineate the seawater intrusion. Existing monitoring wells were used to measure the horizontal and vertical variations
in water salinity and thus to improve the interpretation of earth resistivity imaging data. Results of vertical electrical
soundings and chemical analyses of collected water samples were used to obtain an empirical relationship between the inferred
earth resistivity and the amount of total dissolved solids. This relationship was used along with the true resistivity sections
resulting from the inversion of 2D resistivity data to identify three zones of water-bearing formation (fresh, brackish, and
salt-water zones). Along the four 2D resistivity profiles, the depth to the fresh-brackish interface exceeded 50 m at the
western part of the area and was in the order of 10 m or less in the eastern side near the shoreline. Depth to the brackish-saline
water interface reached about 70 m in the western side and was in the order of 20 m in the eastern side. The thickness of
the fresh water zone decreases considerably in the farming areas toward Kalba and thus the degree of seawater intrusion increases. 相似文献
15.
Neoproterozoic granites of Sharm El-Sheikh area,Egypt: mineralogical and thermobarometric variations
Mohamed?F.?GhoneimEmail author Mohamed?Th.?S.?Heikal Bothina?T.?El?Dosuky Tamer?S.?Abu-Alam Mahmoud?I.?Sherif 《Arabian Journal of Geosciences》2015,8(1):125-141
Calc-alkaline and alkaline intrusions of the late Neoproterozic form essential part of the Arabian–Nubian Shield. They were formed during the collision between East- and West-Gondwana. Sharm El-Sheikh area, Sinai, includes wide compositional array of these intrusions that can be considered as a case study. Variations in both tectonic and thermobarometric condition for granitic intrusions are studied. Four mappable granitic types are recognized namely monzogranite, syenogranite, alkali feldspar granites, and riebeckite-bearing granites. The monzogranite and the syenogranite of the study area are mostly I-type, whereas the alkali feldspar granite and the riebeckite-bearing granite belong to A-type granitoid. The calc-alkaline intrusions were formed in compressional setting due to decompressional melting of mafic lower crust. Partial melting and anatexing of crustal rocks are suggested to explain the protolith of the alkaline intrusions. The transition from the calc-alkaline magma to the alkaline one occurred as a result of the tectonic transition from compression regime to tectonic relaxation (extension setting) during the last stage of the Pan-African Orogeny. The amphiboles of the studied granites are classified as calcic- and alkali-amphiboles. The calcic-amphiboles are ferro-edenite while the alkali-amphiboles are typically riebeckite. Both amphibole types are of magmatic nature. Coexisting amphiboles and plagioclases are used to estimate the physicochemical parameters of magma crystallization. The syenogranite underwent temperature and pressure of formation range of 520–730 °C, <3 kbar. The alkali feldspar granite records 450–830 °C, <4 kbar, while the riebeckite-bearing granite records the lowest temperature condition among all varieties and estimate formation at 350–650 °C, <4 kbar. 相似文献
16.
M. M. Sherif A. M. Ebraheem M. M. Al Mulla A. V. Shetty 《Environmental Earth Sciences》2018,77(11):412
In this study, the first groundwater recharge map for United Arab Emirates (UAE) was developed using the recharge potential and water table fluctuation methods. Recharge potential estimates were made using information about infiltration rate, soil type, ground slope, geological and hydrogeological factors, and the availability of rainfall harvesting infrastructure and were validated by measurements of water table rise in alluvial aquifers in wadis. Based on this information, the total recharge in the UAE is estimated to be about 133 million cubic meters per year (MCM/year). Annual recharge rates are calculated to vary between 1 and 28% of precipitation in the different regions of UAE depending on several natural and manmade parameters including, among others, recharge enhancing infrastructure. Estimates from the two methods are 98% in agreement; which suggests that the recharge potential method is suitable for estimating aquifer’s recharge in UAE and arid regions. The water table fluctuation method was found to be more suitable for assessing recharge through gravel plains and wadis in mountainous areas. 相似文献
17.
Two stratigraphic sections of the Hamam Formation (Bathonian Stage, Middle Jurassic) exposed in the western part of Wadi Zarqa region, northwestern Jordan, are described and interpreted on the basis of palynoflora and facies analysis in order to reconstruct their depositional environments and sequence stratigraphic framework, which not discussed before. Five facies associations have been identified in the Hamam Formation characterized by a mixed carbonate–siliciclastic ramp setting, ranging from incised fluvial valley fill facies, beach foreshore restricted inner ramp to high-energy shoals and mid-ramp settings. The palynoflora includes well-preserved miospore assemblages which are recorded only from the incised fluvial valley fill facies for the first time and yielded 64 miospore species belonging to 40 genera. Most of these taxa are long-ranging and have been reported from Jurassic and Cretaceous rocks worldwide, except Callialasporites dampieri, Murospora florida, Granulatisporites jurassicus, Piceites expositus, Pityosporites parvisaccatus, Leptolepidites verrucatus, and Protopinus scanicus which have short ranges in the Middle Jurassic. Furthermore, these rocks are rich in shallow-marine Neo-Tethys macro-invertebrates supporting a Bathonian age. Two third-order depositional sequences bounded by three regional unconformities at the Bajocian–Bathonian and Bathonian–Callovian stage boundaries as well as within the Bathonian are defined based upon facies characteristics and stratal geometries. A regional correlation of sequence boundaries of similar age indicates that they are eustatic in origin. 相似文献
18.
Several investigations have recently considered the possible impacts of climate change and seawater level rise on seawater intrusion in coastal aquifers. All have revealed the severity of the problem and the significance of the landward movement of the dispersion zone under the condition of seawater level rise. Most of the studies did not consider the possible effects of the seawater rise on the inland movement of the shoreline and the associate changes in the boundary conditions at the seaside and the domain geometry. Such effects become more evident in flat, low land, coastal alluvial plans where large areas might be submerged with seawater under a relatively small increase in the seawater level. None of the studies combined the effect of increased groundwater pumping, due to the possible decline in precipitation and shortage in surface water resources, with the expected landward shift of the shore line. In this article, the possible effects of seawater level rise in the Mediterranean Sea on the seawater intrusion problem in the Nile Delta Aquifer are investigated using FEFLOW. The simulations are conducted in horizontal view while considering the effect of the shoreline landward shift using digital elevation models. In addition to the basic run (current conditions), six different scenarios are considered. Scenarios one, two, and three assume a 0.5 m seawater rise while the total pumping is reduced by 50%, maintained as per the current conditions and doubled, respectively. Scenarios four, five, and six assume a 1.0 m seawater rise and the total pumping is changed as in the first three scenarios. The shoreline is moved to account for the seawater rise and hence the study domain and the seaside boundary are modified accordingly. It is concluded that, large areas in the coastal zone of the Nile Delta will be submerged by seawater and the coast line will shift landward by several kilometers in the eastern and western sides of the Delta. Scenario six represents the worst case under which the volume of freshwater will be reduced to about 513 km3 (billion m3). 相似文献
19.
Harrat Lunayyir is one of the smaller lava fields in western Saudi Arabia that is of current interest due to a dike intrusion episode in 2009, an ongoing swarm of earthquakes and the possible hazard that pose. In addition to seismology, other geophysical data have been used to study the structure of the area, and the available aeromagnetic information is shown and discussed here. The reduced to the pole (RTP) magnetic grid and its enhancements have been used to define some of the main anomalies, and these have been correlated with the known geology, including the Red Sea coastal dike system. There are numerous linear features that are possibly related to the dikes or faulting, but within the area of the harrat, details due to the underlying structure are largely obscured by the magnetic surface lavas. Northeasterly trends in the magnetic data may indicate old zones of weakness that intersect one of the main coastal dikes at the location of the recent seismic activity and surface fissure, suggesting that this is a point of weakness resulting in the volcanism and seismicity that also appears to be largely limited to two of the NE trends. The association of the recent seismicity with a known geological and aeromagnetic feature is important in determining the seismic hazard for the region, especially if the location of future activity can be used to reduce overall uncertainty in the analysis by identifying potential fault sources. Here, the seismicity appears to lie on one of the NNW-trending coastal dikes that have been reactivated recently along a section between two NE-trending older faults. 相似文献
20.
Behzad Amir-Faryar M. Sherif Aggour Richard H. McCuen 《Geomechanics and Geoengineering》2017,12(1):60-71
Numerous model forms have been used to predict the dynamic behaviours of soils, mainly the shear modulus and material damping. These models are used to represent normalised shear modulus reduction and material damping curves. The majority of the existing models are empirical and were proposed for specific soil types, strain ranges, etc. Some are limited to the data used in fitting, but fail to provide a good fit to other sets of data. The available model functions are not universal, which means that a model developed for one soil type may not be applicable for use with other soil types. In this paper, two universal mathematical models were proposed to predict the normalised shear modulus reduction and material damping curves. The mathematical model forms are sufficiently flexible to be widely used with different soil types. The models were evaluated using verification data of eight different soil types, i.e., data that were not used to fit the model parameters. The results indicate that the proposed model forms can accurately model the dynamic soil properties within the typical earthquake range. The advantage of developing the two universal models are two-fold, first the forms are applicable for sand, clay, and fibre-soil composite and second with further testing of soils, the model coefficients could ultimately be used to further understand the physical processes in soil behaviour, especially damping. 相似文献