Abdelaziz Ads

Abdelaziz  Ads

Tanta University

H-index: 5

Africa-Egypt

Abdelaziz Ads Information

University

Tanta University

Position

Assistant lecturer Structural engineering department Faculty of engineering

Citations(all)

99

Citations(since 2020)

99

Cited By

0

hIndex(all)

5

hIndex(since 2020)

5

i10Index(all)

4

i10Index(since 2020)

4

Email

University Profile Page

Tanta University

Abdelaziz Ads Skills & Research Interests

Geotechnical Engineering

Offshore foundations

Foundation engineering

Top articles of Abdelaziz Ads

Effect of fin width on torpedo anchor penetration and pullout using model tests with transparent soils

Torpedo anchors are increasingly popular for tethering of offshore structures. Using fins improves their directional stability during penetration, however, fins’ shape affects both penetration depth and pullout capacity. Experiments were carried out to investigate the effect of the width of fins on the behavior of torpedo anchors during penetration and extraction. Four torpedo models having the same weight were made, one without fins and three with four fins. A transparent soil was used to simulate soft marine clay, thus permitting visualizing torpedo soil interaction. Particle trajectories showed that soil movements in the vicinity of the torpedo were downward as the torpedo approached a given depth, and that movements reversed to upwards once the torpedo passed that depth. Measurements of soil displacements suggest that the pullout capacity of finless torpedoes depends on the friction with the shank, and for …

Authors

Abdelaziz Ads,Magued Iskander,Stephan Bless,Mehdi Omidvar

Journal

Ocean Engineering

Published Date

2024/4/15

Lessons in geomechanics of deep foundations from nature

The field of bio-inspired design has been explored extensively in some engineering disciplines. However, biomimicry remains an area under development for geotechnics. One natural system that has been the focus of recent work is tree roots. Those structures are able to provide compressive and tensile support for substantial loads through an anchorage system that is more efficient than common manmade piles. Roots have been able to adapt and improve according to their environment, resulting in relatively shallow foundation systems if compared to piles, which require the use of more material to extend to greater depths. This study explores different proposed pile designs based on tree roots and their effects on bearing and uplift capacity. The root structure–soil interaction during loading is visualized using a synthetic transparent sand and 3D-printed tree root inspired models. The transparent soil is made of …

Authors

Abdelaziz Ads,Magued Iskander,Giovanna Pipin

Journal

Acta Geotechnica

Published Date

2023/7/11

Rate Dependence of Penetration Resistance in a Cohesive Soil

Penetration resistance of soils is described in a Poncelet framework in which it is due to the sum of an inertial drag term and a strength-related bearing stress. The problem addressed in this paper is how to determine the Poncelet bearing stress from a conventional cone-penetrometer test (CPT). For the case of a particular saturated sandy clay, it is shown that strength has an exponential dependence on strain rate, determined from unconfined compression experiments, which can be used to account for the difference in strength between a CPT carried out at 0.02 m/s and the strength resisting projectiles traveling impacting at 140–200 m/s. With that correction, the CPT tip resistance can be taken as the Poncelet strength.

Authors

Sophia R Mercurio,Stephan Bless,Abdelaziz Ads,Mehdi Omidvar,Magued Iskander

Published Date

2023/6/5

Longitudinal settlements during tunneling in soft Clay, using transparent soil models

The purpose of this study was to measure internal longitudinal displacements taking place during tunnel excavation and compare them to the displacements predicted using available analytical and empirical formulations. A physical model made with transparent soil permitted exploring the internal soil deformations, within the supporting soils. A soil surrogate made of Magnesium Lithium Phyllosilicate (MLPS) was used to represent soft clay. Tunneling was simulated using a moveable trap door arrangement for different face losses ranging from 5 to 30% D. Internal soil movements in the longitudinal direction were captured for three cover-to-diameter (C/D) ratios ranging from 1.5 to 3.5. Shear as well as volumetric strains were computed using the captured spatial displacements. The results demonstrate that the shape of the longitudinal profile is more dependent on the overburden depth of the tunnel in comparison to …

Authors

Abdelaziz Ads,Md Shariful Islam,Magued Iskander

Journal

Tunnelling and Underground Space Technology

Published Date

2023/6/1

Shape effects on penetration of dynamically installed anchors in a transparent marine clay surrogate

The effect of shape on the penetration of low-speed penetrators, traveling under 10 m/s, such as dynamically installed anchors, gravity-fall penetrometers, projectiles, and unexploded ordnances, is explored. A transparent surrogate was used to simulate the behavior of a soft marine clay to permit visualizing anchor deceleration. Thirteen 19-mm diameter anchors were employed. Geometric parameters included fin shape and longitudinal grooves. Measurements of penetrator deceleration, from which the soil penetration resistance was computed, were further resolved into force on the nose, fins, and frictional forces. For this material, the ratio of nose-bearing stress to the undrained shear strength was about 8.2 and 4.5 for the nose and fins, respectively, and the effective friction coefficient was 0.3. The study demonstrates the effect of various geometric properties of an anchor on its deceleration and depth of burial …

Authors

Abdelaziz Ads,Stephan Bless,Magued Iskander

Journal

Acta Geotechnica

Published Date

2023/6

Large Deformation Explicit Finite Element Simulations of Drop Tower Experiments on Clay

Results of a high strain rate unconfined compression test on a clay soil sample and corresponding finite element simulations are presented. A drop tower was adapted to drop weights onto a saturated cylindrical kaolin clay soil sample. The engineering stress-strain response was found using piezoelectric load cells and a high-speed camera. Remolded cylindrical clay samples were prepared by the static compaction of hydrated clay in a cylindrical mold. The drop tower experiment featured a mass of 13.4 kg dropped from a height of 1.5 m, resulting in an impact velocity of 4.15 m/s and a constant strain rate of 56/s on the soil sample. Results of the high strain rate experiments revealed that the saturated kaolin clay strength, as quantified using the unconfined compressive strength, exhibited significant strain-rate dependence. An approximately 100% increase in the unconfined compressive strength was observed at a …

Authors

R White,M Omidvar,A Ads,S Bless,M Iskander

Published Date

2022/6/13

Visualizing the effect of excavation rate on rock deformation and fracturing of tunnels using a transparent soft rock surrogate

One of the most important problems during tunneling in soft rock is deformation and fracturing of the rock during tunneling. The problem was successfully explored by using a transparent rock surrogate to simulate the behavior of soft rock, which permitted visualizing conditions within the rock. Synthetic soft rock was made using consolidated fused quartz saturated with a blend of two mineral oils that have the same refractive index as the quartz. The tunnel was simulated using a smooth aluminum tube and two tunneling methods representing machining and blasting were considered. Two observation planes made of seeding particles were pre-placed within the model and used to track soil movements and crack propagation. Images of both planes were captured simultaneously using two orthogonal cameras. Rock deformations were concentrated in the vicinity of the tunnel face, and deformation rates behind the …

Authors

Guoan Xu,Magued Iskander,Abdelaziz Ads,Hongwen Jing

Journal

Acta Geotechnica

Published Date

2022/5

Behavior of Torpedo Anchors in a Transparent Soft Marine Clay

Torpedo anchors are increasingly popular for tethering of offshore structures in deep waters. Torpedo anchors have been used for more than two decades. The main advantages of this type of offshore foundation are said to be their low cost due to easy fabrication, little restriction on their use in great water depths, and ability to be used in deep waters. Prior research suggests that the embedment depth as well as pullout capacity depends mainly on the impact velocity, torpedo geometry, the shear strength of the penetrated soil, soil sensitivity, and strain rate. Experiments were carried out in this study to investigate the effect of nose shape, fin lengths, fin widths, and shank shape on the behavior of torpedo anchors during penetration and extraction. Thirteen torpedo models were used in this study. The shank length to diameter ratio was 8. The effect of using conical and hemispherical noses was investigated. Two fin …

Authors

Abdelaziz Ahmed Ads

Published Date

2021

Effect of face losses and cover-to-diameter ratio on tunneling induced settlements in soft clay, using transparent soil models

Reliable prediction of surface and subsurface settlements induced by shallow tunnels is important to minimize the adverse effects which may take place during tunnel excavation. A transparent soil surrogate representing the geotechnical behavior of soft clay was employed to explore spatial soil deformations within the soil mass near the tunnel. Shear strain, volumetric strain, surface and subsurface settlements resulting from increasing face losses were captured for three cover-to-diameter (C/D) ratios. The observed data trends are generally consistent with the data available in the literature, however the ability to visualize soil movements confirmed a number of perceived behaviors. First, the observed subsurface settlements are noticeably larger than surface ones. Second, the observed settlement trough widths are generally wider than the predicted ones, consistent with the low shear strength of the clay simulant …

Authors

Abdelaziz Ads,Md Shariful Islam,Magued Iskander

Journal

Geotechnical and Geological Engineering

Published Date

2021/12

Soil-Structure Interaction of Underreamed Piles

Underreamed piles are cast-in-place drilled shafts that have one or more bulbs added to the straight shaft to increase their axial capacity. The underreams are typically formed by using a belling tool and filling the cavity with plain concrete. This study explores the mechanisms that contribute to the gain in capacity of underreamed piles relative to their straight counterparts. Soil-structure interaction of underreamed piles is explored using a synthetic transparent soil made of fused quartz and a mixture of mineral oils with matched refractive indices. The effect of the number of underreams and the distance between them, as well as the ratio between the diameters of the underreams and the straight shaft, were explored. Several underreamed pile configurations were 3D printed in-house. Load deformation response was obtained during uplift and compressive loading. Soil movements were obtained by tracking the …

Authors

Prabin Poudel,Abdelaziz Ads,Magued Iskander

Published Date

2021

Learning foundation engineering from nature

Bio-inspired design is increasingly popular in a variety of disciplines. Tree roots provide an anchorage system that is significantly more efficient than typical engineered systems. Trees are capable of withstanding substantial axial and lateral loads, with root structures that have improved throughout time. In comparison, engineered piling systems require the foundation to extend deeper in order to support comparable loads to those experienced by trees. This study explores the effect of lateral roots on trees’ bearing and uplift capacity to identify best practices for bio-inspired foundation design. The tree–soil interaction during loading is investigated using a transparent soil representing sand, made of fused quartz and a mixture of mineral oils having a matched refractive index. Load deformation response was obtained during loading. Soil movements were obtained by tracking fused quartz particle movements …

Authors

Giovanna Pipin,Abdelaziz Ads,Magued Iskander

Published Date

2021

Soil–projectile interaction during penetration of a transparent clay simulant

Visualization of soil structure interaction during projectile penetration of clay is made possible by use of a surrogate composed of magnesium lithium phyllosilicate combined with high-speed photography and digital image correlation. A free-falling penetrator striking at 5.5 m/s simulated a projectile. Penetration resistance was constant within the resolution of the experiment; it was mainly due to the bearing resistance of the soil in contact with the nose, rather than skin friction. Bearing resistance in dynamic penetration for a hemispherical-nose rod was about 20% higher than quasi-static tests using a sphere. Bearing resistance was also about 20% higher for a hemispherical nose compared to a conical nose. Cavitation behind the nose is dependent on its shape with soils rebounding toward the projectile for conical noses but not hemispherical ones.

Authors

Abdelaziz Ads,Magued Iskander,Stephan Bless

Journal

Acta Geotechnica

Published Date

2020/4

3D Ground Movements Due to Tunnel Face Collapse

Soil movements due to tunnel face collapse have catastrophic effects on both surface and underground structures and utilities. The aim of this study is to determine the extent of the zone of influence resulting from tunnel face movements, experimentally. Several models made of transparent soils were employed to visualize deformations leading to tunnel-face collapse. A soft transparent synthetic clay made of magnesium lithium phyllosilicate (MLPS), which is commercially known as Laponite RD was employed to simulate a soft marine clay. An embedded plane of seeded particles was used to track soil movements. Digital image correlation (DIC, aka particle image velocimetry, PIV) was employed to obtain deformations perpendicular and parallel to the tunnel face. These deformations were combined to obtain the 3D zone of influence and compute the resulting volumetric and shear strains. The effect of tunnel face …

Authors

Abdelaziz Ads,Magued Iskander,Ashraf K Nazir

Published Date

2020/2/21

Visualizing the effect of Fin length on torpedo anchor penetration and pullout using a transparent soil

The effect of torpedo shape on its penetration depth and pull out capacity is explored using laboratory-scale experiments. The study offers a number of useful practical implications for the design of full-scale torpedo anchors. Results demonstrate that the resistance to penetration and extraction of torpedo anchors is strongly affected by their fin design. A transparent soil surrogate made of Magnesium Lithium Phyllosilicate (MLPS), was employed to simulate soft marine clay. Three torpedo models having a length to diameter (L/D) ratio of eight and a similar weight (W), but different fin length to diameter ratios (LF/D) of zero (no fins), 2.6, and 5.2, were penetrated, vertically, at an impact velocity of 4.5 m/s. It was found that fin length correlated negatively with penetration depth (P) and positively with the maximum resistance to extraction. However, the maximum extraction resistance, normalized by weight (W), increased …

Authors

Abdelaziz Ads,Magued Iskander,Stephan Bless,Mehdi Omidvar

Journal

Ocean Engineering

Published Date

2020/11/15

Rate dependent penetration of dry sand

Penetration of sand is described with a Poncelet equation. Values of Poncelet parameters that can be used for a generic quartz sand were derived from the literature and from new experiments at relatively low velocities. Values of the Poncelet drag parameter and 0.85 and resisting strength of 500 kPa should be used to estimate penetration, unless specific data for the soils of interest are available.

Authors

S Bless,M Omidvar,M Iskander,A Ads

Journal

AIP Conference Proceedings

Published Date

2020/11/2

Static and dynamic analysis of torpedo anchor penetration and pullout in cohesive soils

This paper investigates the mechanics of torpedo-anchors’ soil interactions in a transparent synthetic surrogate for marine clay, during both embedment and extraction. Both free falling and quasi-statically advanced torpedo anchors were included to cover a range of rates spanning three orders of magnitude (V/D of 0.2-200 s-1, where V is penetration velocity, and D is torpedo diameter). Impact velocities in the range of 5.0 m/s were investigated. Digital image correlation (DIC) was employed to analyze images of penetration and pullout, captured at a framerate that permitted quantifying incremental displacements. Penetration resistance was found to depend on nose shape. Two nose shapes were studied, and hemispherical noses engendered larger resistance than conical ones; however, shaft resistance is higher behind conical noses, so the combined effect on penetration of a full torpedo is minimal. Resistance …

Authors

Abdelaziz Ads,Mehdi Omidvar,Stephan Bless,Magued Iskander

Published Date

2020/2/21

Impact and penetration of a transparent cohesive soil

Experiments were designed to study the terminal phase of penetration in a synthetic soft clay. Rod-cone projectiles were launched at speeds of approximately 5 m/s into a saturated soft transparent surrogate for saturated marine clay. Quasi-static tests were also performed into the same material. The average penetration resistance was 22 kPa. It was found that rate effects and shaft resistance were relatively small. A practical result is that resistance to dynamic penetration in this material can be estimated from quasi-static cone penetration tests. The stress (load/area) required to extract penetrators was very similar to the penetration resistance.

Authors

S Bless,A Ads,M Iskander,M Omidvar

Journal

AIP Conference Proceedings

Published Date

2020/11/2

Influence of Footing Shape on the Bearing Capacity of Soft Clay

Most marine structures tend to use deep foundations. However, using shallow foundations would be a more cost-effective alternative for some situations, especially for subsea infrastructure. An important factor in the general bearing capacity equation is the shape factors. In this study, the effect of different footing shapes on the bearing capacity of marine soft clay was investigated, with the aid of a transparent soil that permits visualizing deformations within it. Five shapes having the same cross-sectional area and the same material properties were used. The marine soft clay was simulated by a synthetic transparent soil made of magnesium lithium phyllosilicate (MLPS). The undrained shear strength was measured using a miniature ball penetrometer. An embedded seeded plane was employed to track soil movements. Those movements were captured by a high-speed camera, and the resulting images were analyzed …

Authors

Giovanna Pipin,Abdelaziz Ads,Magued Iskander

Published Date

2020/2/21

Shear strength of a synthetic transparent soft clay using a miniature ball penetrometer test

This article is concerned with the properties of Laponite colloids, which are being used as a transparent surrogate for soft natural clays. Laponite is a synthetic smectite clay similar to natural hectorite clay that is made of magnesium lithium phyllosilicate (MLPS). The effect of aging on the shear strength of transparent soft clay formed from MLPS and water is presented in this article. A miniature ball penetrometer (MBP) was developed for this study. MBP tests were used to measure the shear strength of samples at three different concentrations of MLPS in water. Sodium pyrophosphate was used to slow down the flocculation of MLPS by altering its rheology, thus improving the transparency of higher MLPS concentration samples. Parameters that were studied included the water quality, aging, penetration rate, penetrometer geometry, and repeatability. The strength of clays made of MLPS was found to increase with …

Authors

Abdelaziz Ads,Magued Iskander,Stephan Bless

Journal

Geotechnical Testing Journal

Published Date

2020/9/1

See List of Professors in Abdelaziz Ads University(Tanta University)

Abdelaziz Ads FAQs

What is Abdelaziz Ads's h-index at Tanta University?

The h-index of Abdelaziz Ads has been 5 since 2020 and 5 in total.

What are Abdelaziz Ads's top articles?

The articles with the titles of

Effect of fin width on torpedo anchor penetration and pullout using model tests with transparent soils

Lessons in geomechanics of deep foundations from nature

Rate Dependence of Penetration Resistance in a Cohesive Soil

Longitudinal settlements during tunneling in soft Clay, using transparent soil models

Shape effects on penetration of dynamically installed anchors in a transparent marine clay surrogate

Large Deformation Explicit Finite Element Simulations of Drop Tower Experiments on Clay

Visualizing the effect of excavation rate on rock deformation and fracturing of tunnels using a transparent soft rock surrogate

Behavior of Torpedo Anchors in a Transparent Soft Marine Clay

...

are the top articles of Abdelaziz Ads at Tanta University.

What are Abdelaziz Ads's research interests?

The research interests of Abdelaziz Ads are: Geotechnical Engineering, Offshore foundations, Foundation engineering

What is Abdelaziz Ads's total number of citations?

Abdelaziz Ads has 99 citations in total.

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