Advanced Mathematical Models to Predict the Compaction Properties of Coarse-Grained Soils from Various Physical Properties     

Maher Omar  Abdallah Shanableh  Mohamed Arab  Khaled Hamad  Ali Tahmaz 《Geotechnical and Geological Engineering》2018,36(6):3467-3483

An essential task in the process of construction is the determination of compaction properties of soils. Many years of laboratory test experience strengthen our belief in the existence of predictive equations that govern the compaction characteristics of soils. An advanced mathematical model developed in this research in order to uncertain the governing equations. An advanced mathematical model developed in this research in order to uncertain the governing equations. Through a comparative study among a Multiple Linear Regression (MLR) model, an Artificial Neural Network (ANN) model, Extreme Learning Machine (ELM) and a Support Vector Machine (SVM) model, the best predicting model was determined. For this purpose, Six hundred and six (606) samples collected and split into a dataset used for training the models and another used for validation of the derived model. 8 neural networks with a varying number of hidden layers and a varying number of nodes in hidden layers were employed. In ELM 1 hidden layer with varying number of units were employed. It was found that the equations derived from the ELM models described the relationship with superiority over multiple regression, ANN and SVM models for Maximum Dry Density and MLR models described the relationship with superiority over ANN, ELM and SVM models for Optimum Moisture Content.  相似文献   

Impact of the geomorphology and soil management on the development of waterlogging in closed drainage basins of Egypt and Saudi Arabia   总被引：1，自引：0，他引：1  

Mohammed El Bastawesy  Rafat Ramadan Ali  Khalid Al Harbi  Abdallah Faid 《Environmental Earth Sciences》2013,68(5):1271-1283

This paper investigates the interplay of the catchment geomorphology, hydrology and soil properties on the development of waterlogging and land degradation within different dry land catchments in Egypt and Saudi Arabia. Multi-temporal remote sensing data of the Landsat Thematic Mapper and Enhanced Thematic Mapper were collected and processed to detect the land cover changes and development of cultivations within the two areas. The Shuttle Radar Topography Mission Digital Elevation Model were hydrologically processed to delineate the catchment morphometrical parameters and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The fluvial channels of the Farafra Oasis have largely been obliterated by the prevailing aridity and often buried under aeolian deposits. The soil of these areas are mainly lithic with a high calcium carbonate content, thus limiting the downward percolation of excess irrigation water and therefore develop perched water table and seepage through the buried fluvial channels. On the other hand, the cultivations of Tabuk catchment (which has similar geomorphologic setting to the Farafra Oasis) have shown no signs for waterlogging. This situation is could be related to the different soil properties; the spatial distribution of cultivated areas and the adopted irrigation methods via pivots. The inactive alluvial channels, landforms and irrigation methods have to be considered when planning for a new cultivation in dry land catchments to better control waterlogging hazard. The ‘dry-drainage’ concept can be implemented as the drainage and seepage water, which can be conveyed into certain abandoned playas for evaporation.  相似文献   

Geophysical prediction and following development sinkholes in two Dead Sea areas, Israel and Jordan   总被引：2，自引：0，他引：2  

M. G. Ezersky  L. V. Eppelbaum  A. Al-Zoubi  S. Keydar  A. Abueladas  E. Akkawi  B. Medvedev 《Environmental Earth Sciences》2013,70(4):1463-1478

Geophysical methods—seismic refraction (SRFR), electrical resistivity tomography (ERT), and microgravity—were applied to the Dead Sea (DS) sinkhole problem in the Ein Gedi area at the earlier stage of the sinkhole development (1998–2002). They allowed determining the sinkhole formation mechanism and localizing the sinkhole hazardous zones. The SRFR method permitted to delineate the underground edge of a salt layer at the depth of 50 m. The salt edge was shaped like the sinkhole line on the surface. It was concluded that the sinkhole development is linked to the salt edge. Geoelectrical quasi-3D mapping based on the ERT technique detected large resistivity anomalies with 250–300 m² diameter and 25–35 m deep. The Ein Gedi area has been also mapped by the use of Microgravity method. The residual Bouguer gravity anomaly map shows negative anomalies arranged along the edge of the salt layer. Those gravity anomalies overall are very similar in plan to the resistivity distribution in this area. The results of forward modeling indicate that both high resistivity and residual gravity anomalies are associated with a subsurface decompaction of the soil mass and deep cavity at the sinkhole site. Following monitoring of the sinkhole development carried out by the Geological Survey of Israel confirmed our suggestions. The drilling of numerous boreholes verified the location of the salt edge. Geographical Information System (GIS) database testifies that during 2003–2009 new sinkholes are continuing to develop along the salt edge within a narrow 50–100 m wide strip oriented approximately in north–south direction (slightly parallel to the shoreline). No promotion in west–east direction (perpendicularly to the DS shoreline) was observed in Israel. Collapse of sinkholes and their clustering have been occurred within the area of high resistivity anomaly and negative residual gravity anomaly. Similar studies carried out at the Ghor Al-Haditha area (Jordan) have shown that sinkholes there are also arranged along the winding line conforming to the salt edge. In this area sinkholes are slowly moved to the Dead Sea direction. Results of geophysical studies in numerous DS sites indicate similar sinkhole development. It allowed generating of the sinkhole formation model based on ancient (10,000–11,000-year old) salt belt girding the Dead Sea along its shores  相似文献   

Interactions between the surface water and groundwater in the western shoreline of Lake Nasser, Upper Egypt     

Ali M. Hamdan  Sayed A. Selim  Mohamed M. Abdallah 《Arabian Journal of Geosciences》2013,6(1):77-84

The present study indicates that the factors controlling the hydraulic relation between surface water and groundwater at the western lake shoreline change from one locality to another. This depends upon the lithological characteristics and the major structures. In the southern sectors, sedimentation at the bottom and sides of the lake prevents the water movement to the Nubian sandstone aquifer. The potentiometric map reveals that the water level altitudes range between 170 m in the vicinity of the lakeshore line and 110 m west of the lake. The groundwater flow lines show that the main recharge to the aquifer comes from the southwest direction, as well as from the lake inland to variable distances (about 30 Km). During the present study, Darcy’s law was applied to calculate the recharge from the western shoreline of Lake Nasser to the adjacent Nubian aquifer. The maximum value of seepage was at Garf Hussein (27.71?×?10⁶ m³/year), which may be related to high permeability and hydraulic gradient. Also, it may be related to the N–S strike faults that cut the area on both sides of the Lake, and the groundwater is expected to have free circulation through the faults of this trend. The minimum value was recorded in Adindan section (0.61?×?10⁶ m³/year). This may be related to the limited recharge from the lake to the aquifer, due to the sedimentation that dislocates this recharge.  相似文献   

Soil and bedrock distribution estimated from gully form and frequency: A GIS-based decision-tree model for Lebanon   总被引：2，自引：1，他引：1  

Rania Bou Kheir  Jean Chorowicz  Chadi Abdallah  Damien Dhont 《Geomorphology》2008,93(3-4):482-492

Torrential rainfall and relatively sparse vegetation in the Mediterranean region result in the development of gully systems and land degradation, notably on lands with specific types of soil and bedrock. This paper proposes a decision-tree model to predict the distribution of soil and bedrock susceptible to gully erosion (white Rendzinas and marly rocks) from the form and frequency of gullies. The study area is located in Lebanon and the model is linked to GIS. V-fold cross-validation of the pruned model indicates that gully features including cross-section size and shape, network frequency, types of meandering, and catchment area can explain 80% of variance in soil/rock properties. The overall accuracy of the soil/rock map was estimated to be ca. 87%. The proposed model is relatively simple, and may also be applied to other areas. It is particularly useful when information about soil and rock obtained from conventional field surveys is limited.  相似文献   

Pressuremeter test parameters of a compacted illitic soil under thermal cycling     

H. Eslami  S. Rosin-Paumier  A. Abdallah  F. Masrouri 《Acta Geotechnica》2017,12(5):1105-1118

The incorporation of heat exchangers in geostructures changes the temperature of the adjacent soil, raising important issues concerning the effect of temperature variations on hydro-mechanical soil behaviour. The objective of this paper is to improve the understanding and quantification of the impact of temperature variation on the bearing capacity of thermo-active piles. Currently, the design of deep foundations is based on the results of in situ penetrometer or pressuremeter tests. However, there are no published data on the effect of temperature on in situ soil parameters, preventing the specific assessment of the behaviour of thermo-active piles. In this study, an experimental device is developed to perform mini-pressuremeter tests under controlled laboratory conditions. Mini-pressuremeter tests are performed on an illitic soil in a thermo-regulated metre-scale container subjected to temperatures from 1 to 40 °C. The results reveal a slight decrease in the pressuremeter modulus (E _p) and a significant decrease in the creep pressure (p _f) and limit pressure (p _l) with increasing temperature. The results also reveal the reversibility of this effect during a heating–cooling cycle throughout the investigated temperature range, whereas the effect of a cooling–heating cycle was only partially reversible. In the case of several thermal cycles, the effect of the first cycle on the soil parameters is decisive.  相似文献   

Understanding groundwater chemistry in Mediterranean semi-arid system using multivariate statistics techniques and GIS methods: case of Manouba aquifer (Northeastern Tunisia)   总被引：1，自引：0，他引：1  

Hajer Ferchichi  Boutheina Farhat  Mohamed F. Ben-Hamouda  Abdallah Ben-Mammou 《Arabian Journal of Geosciences》2017,10(23):530

The rapid urbanization and industrialization of the Manouba plain (Northeastern Tunisia), the extensive agricultural expansion and the succession of dry years during recent decades have exerted greatly load on the water needs and lead to groundwater quality degradation. The aim of this study is to evaluate the processes controlling the groundwater mineralization of the shallow aquifer for determining its suitability for drinking and agricultural purposes. For establishing that, we combine several geological, hydrological and hydrochemical data with geostatistical techniques. The samples were collected at 17 sites covering 230 km² of the study area and analyzed for major and trace components. The total dissolved solid (TDS) content ranges from 1372 to 3999 mg/l. The results of Piper diagram indicate that Na⁺/Cl^? and Ca²⁺?>?Na⁺/SO₄ ^2? were the main dominant water types localized in the sloping sides of the watershed and near the saline depression; the suitability for irrigation use was also evaluated. The high concentrations of nitrates and chlorides are indicators of anthropogenic pollution, like the agricultural over application of nitrogen fertilizers and the discharge of domestic and industrial wastewater. Saturation indexes calculated by using PHREEQC (USGS) program show that groundwaters are undersaturated with evaporitic minerals (halite, gypsum) and saturated with carbonates (calcite, aragonite). The use of principal component analysis and hierarchical cluster analysis has shown that two main factors accounting 67.13% of the information of variability within the dataset confirm the existence of dissolution of evaporitic minerals and the mechanisms of nitrate increasing the salinity of the Manouba groundwater.  相似文献   

Interpretation of magnetic resonance soundings in rocks with high electrical conductivity   总被引：1，自引：0，他引：1  

A. Legchenko  M. Ezersky  J.-F. Girard  J.-M. Baltassat  M. Boucher  C. Camerlynck  A. Al-Zoubi   《Journal of Applied Geophysics》2008,66(3-4):118

Magnetic resonance sounding (MRS) is an electromagnetic method designed for groundwater investigations. MRS can be applied not only for studying fresh-water aquifers, but also in areas where intrusion of saline water is rendering the subsurface electrically conductive. In the presence of rocks with a high electrical-conductivity attenuation and a phase shift of the MRS signal may influence the efficiency of the MRS method. We investigated the performance of MRS for allowing us to propose a procedure for interpreting MRS data under these conditions. For numerical modeling, we considered a subsurface with a resistivity between 0.5 and 10 Ω m. The results show that the depth of investigation with MRS depends upon the electrical conductivity of groundwater and surrounding rocks, on the depth of the saline water layer, and on the amount of fresh water above the saline water. For interpreting MRS measurements, the electrical conductivity of the subsurface is routinely measured with an electrical or electromagnetic method. However, due to the equivalence problem, the result obtained with these methods may be not unique. Hence, we investigated the influence of the uncertainty in conductivity distribution provided by transient electromagnetic measurements (TEM) on MRS results. It was found that the uncertainty in TEM results has an insignificant effect on MRS.  相似文献   

Seismic performance of high-rise buildings in selected regions in Saudi Arabia according to different seismic codes     

Sayed Mahmoud  Mohamed Alsearheed  Waleed Abdallah 《地震工程与工程振动(英文版)》2021,(1):179-191

The design code for each country is revised and updated based on an expected zone’s seismic intensities,geotechnical site classifications,structural systems,construction materials and methods of construction in order to provide more realistic considerations of seismic demand,seismic response,and seismic capacity.Based on the aforementioned provisions,structures designed according to different seismic codes may yield different performances for the same level of hazard.This study aims to investigate and compare the induced responses related to the earthquake-resistant design of reinforced concrete(RC)buildings according to the Saudi building code(SBC-301),American code(ASCE-7),uniform building code(UBC-97),and European code(EC-8).In order to account for the provision regarding the hazard specification and its effect on the induced seismic responses,four regions in the Kingdom of Saudi Arabia with different seismic levels are selected.The code provisions related to the specification of site classification and its effect on the induced design base shear are investigated as well.Significant differences are observed in the induced responses with the variation in seismic design codes for the considered seismic hazards and site classifications.  相似文献   

Parametric study using FEM for the stability of the RCC Tannur dam     

Samer?A.?BarakatEmail author  Abdallah?I.?Husein?Malkawi  Maher?Omar 《Geotechnical and Geological Engineering》2005,23(1):61-78

Parametric study was carried out in this paper using the Finite Element Method (FEM) to study the effects of variations of the two parameters, i.e., variations in batter slope and foundation properties under static and dynamic loading conditions on the distribution of the peak stresses within the dam and foundation soils. The response spectra for the operating basis earthquake (OBE) and the maximum credible earthquake (MCE) were used in the dynamic analysis. It is shown that the distribution of peak stresses across base of dam and the extent of tensile zone on the foundation soils at the foundation level vary with the variations in the batter slope. Generally, as the batter slope increases the extent of the tensile zone at the foundation level decreases but not necessarily the maximum tensile stresses. However, an optimum batter slope could be achieved based on the results of this parametric study. It should be noted that the greatest tension is developed in the rock adjacent to the toe of the batter. For the foundation mechanical properties, it has been shown that the assessment of accurate soil mechanical properties has a great effect on the computed design stresses from finite element analysis. However, the greatest effect of the foundation properties was on the stresses at the base of dam while it has a negligible effect within the dam body.  相似文献