Experimental evaluation of the performance of earth levees deteriorated by wildlife activities

In this study, an earth levee model is constructed to investigate the impact of animal burrows on the integrity and performance of earthen structures. A series of centrifuge experiments are conducted on homogenous scaled-down 1H:1V levee models built from the natural Kasama soil. Both intact and deteriorated models were subject to a 35g acceleration level. Invasive animal intrusions were introduced in the form of horizontal array of idealized cylindrical burrows at the mid-height of the levee. The water level was gradually increased during the centrifuge flight, and the response of the levee was monitored throughout the test. Pore pressures were recorded using pressure transducers placed at preselected locations within the model. Surface displacements were measured using laser LVDTs and supplemented with three digital cameras for tracking the overall deformation pattern of the levee model. A summary of the test procedure and selected results is presented herewith. The observed deformation mechanism due to the presence of animal burrows is also described. As compared with the intact levee, the presence of burrows is found to alter the pattern of the water flow through the deteriorated levee structure—leading to a notable increase in the exit hydraulic gradient, internal erosion, and subsequently slope failure.     

Three-dimensional finite element analysis of spatially variable PVD improved ground

A stochastic approach that investigates the effects of soil spatial variability on stabilisation of soft clay via prefabricated vertical drains (PVDs) is presented and discussed. The approach integrates the local average subdivision of random field theory with the Monte Carlo finite element (FE) technique. A special feature of the current study is the investigation of impact of spatial variability of soil permeability and volume compressibility in the smear zone as compared to that of the undisturbed zone, in conjunction with uncoupled three-dimensional FE analysis. A sensitivity analysis is also performed to identify the random variable that has the major contribution to the uncertainty of the degree of consolidation achieved via PVDs. The results of this study indicate that the spatial variability of soil properties has a significant impact on soil consolidation by PVDs; however, the spatial variability of soil properties in the smear zone has a dominating impact on soil consolidation by PVDs over that of the undisturbed zone. It is also found that soil volume compressibility has insignificant contribution to the degree of consolidation estimated by uncoupled stochastic analysis.     

Ecohydrology and flood risk management under climate vulnerability in relation to the sustainable development goals (SDGs): a case study in Nagaa Mobarak Village,Egypt

Natural Hazards - This article aims to provide a thorough assessment of water quality and quantity incorporating the estimation of future patterns as a result of climate change from economic,...     

Voronoi Meshing to Accurately Capture Geological Structure in Subsurface Simulations

Mathematical Geosciences - Mesh generation lies at the interface of geological modeling and reservoir simulation. Highly skewed or very small grid cells may be necessary to accurately capture the...     

Mapping Structurally Controlled Alterations Sparked by Hydrothermal Activity in the Fatira–Abu Zawal Area, Eastern Desert, Egypt

The Eastern Desert of Egypt suffered a protracted period of deformation triggered by cratonization of the new juvenile crust known as the Arabian Nubian Shield (ANS), which has been proposed for potential gold discoveries associated with the corresponding tectonic event. The Fatira area, on the border of Egypt''s Northern and Central Eastern Deserts, is covered with metavolcanic rocks twisted by a dextral relocation of the Fatira Shear Zone (FSZ) relative to the Barud magmatic body. The recent study evaluated many deformed post-orogenic granitic intrusions and felsite dikes associated with promising mineralization localities, notably orogenic gold deposits. The combination of various field observations and remote sensing data, followed by the analysis of aeromagnetic enhanced maps, allowed the differentiation of distinct lithologies, structural features, and hydrothermal alterations in the study area. Additionally, the integrated results obtained from the different interpretation techniques are utilized to identify and confirm the previously supposed mineralized localities in the Fatira and Abu Zawal areas and predict other matched localities. The final ASTER, Sentinel 2 hydrothermal alteration, and orientation entropy heat maps demonstrate the association between these mineralized regions and major structures related to the FSZ late stage of deformation rather than other structures studied throughout the area of interest.