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Papers by Mahmoud Awad-Allah
Journal of Al-Azhar University Engineering Sector, 2019
Slope-stability failures have occurred in several improper landfills and illegal dumping sites. T... more Slope-stability failures have occurred in several improper landfills and illegal dumping sites. To investigate the shear response of municipal solid waste (MSW), it is significant to consider the stability of dumping site and landfill design. In the present paper, the shear response and shear strength of MSW recovered from four different landfill sites (in Japan and China) were investigated using a developed in-situ direct shear test apparatus. Moreover, the paper introduces the steps for preparation of undisturbed samples and test procedures in details to determine the in-situ shear strength characteristics (c and φ) of MSW. The in-situ experimental results indicated that the shear response of waste materials affected by the existence of fibrous materials. In addition, the values of cohesion and friction parameters of waste materials strongly depended on the percent of fibrous materials. Results of geotechnical investigations and slope stability studies of landfill sites have been also introduced.
Innovative Infrastructure Solutions, Feb 7, 2022
Shear strength properties of fibrous waste materials, which are found in most of landfill sites, ... more Shear strength properties of fibrous waste materials, which are found in most of landfill sites, play a significant role in the stability of side slopes of those sites. Recent records revealed that slope failures have occurred in several improper dumping and illegal landfill sites at some countries. Therefore, this paper introduces field and numerical studies to assess the shear strength properties of fibrous waste materials at locations of some municipal solid waste (MSW) sites. In the present study, shear response and shear strength of waste materials obtained from four different landfill sites were investigated using an especial developed in situ direct shear test apparatus. Moreover, the paper introduces the steps for preparation of undisturbed samples and test procedures in details to determine the in situ shear strength characteristics ( c and φ ) of MSW. The field experimental results indicated that the shear response of waste materials affected by the existence of fibrous materials contents in the MSW materials. In addition, the values of cohesion and friction parameters of waste materials strongly depend on the percent of fibrous materials. Furthermore, based on the field test results, numerical methods have been implemented in this work (i.e., FEM and LEM) to evaluate safety factors of side slopes, lateral and vertical deformations which usually occur during shearing and external loads.
Innovative Infrastructure Solutions, 2022
This paper introduces an investigation using 3-D finite element method (FEM) and empirical method... more This paper introduces an investigation using 3-D finite element method (FEM) and empirical methods for prediction of pull-out resistance (skin friction) of ground anchors installed in soil, and soft rock formations are presented. Four full-scale ground anchor tests installed into different soils and rock types namely, clay, silty sand, and sandstone, were carried out. The tests were performed up to twice of working loads or failure loads so that the ultimate skin friction resistance for each soil/rock strata under the pull-out loads was estimated. Furthermore, an extensive site investigation campaign was performed to predict the in situ soil/rock characteristics. Field test setup and installation method of the full-scale ground anchors were presented in details. FEM (Plaxis 3D subroutine) was used to verify the results of the pull-out field tests. Besides, the measurements of the field tests were compared with the values of unit skin friction resistance given by the well-known codes of practice (AASHTO, and BS 8081) for design of ground anchorage. It was found that the proposed 3-D FEM and the adopted constitutive models provided good agreement with the field test results.
The International Conference on Civil and Architecture Engineering, 2012
Pile foundations supporting bridge piers, offshore platforms, and towers are required to resist n... more Pile foundations supporting bridge piers, offshore platforms, and towers are required to resist not only static loading but also cyclic or dynamic lateral loading resulted from winds, sea waves, or earthquake actions. Therefore, it is necessary to examine the effects of slow cyclic loads on the pile foundation behavior. This paper presents an experimental study on pile models of different arrangements founded in both dense and loose sands of relative densities equal to D r =75% and 35%, respectively. In this work, series of two-way lateral cyclic loading tests were performed on three pile arrangements (single, 3 ×1, and 3×3 groups) having length to diameter ratio (L/d) of 10 and 20 with spacing to diameter ratio (S/d) of 3. The experimental setup was explained in details and the results were presented in the form of cyclic load-deflection curves and normalizedbending moment charts against the number of cycles. Moreover, cyclic group efficiency, and cyclic p-multipliers were evaluated.
In this paper, a comparison study based on results of experimental lateral pile load tests was ca... more In this paper, a comparison study based on results of experimental lateral pile load tests was carried out between a new proposed method and widely used methods for predicting the ultimate lateral resistance of piles in sandy soil. The proposed technique agrees well with those obtained from the centrifuge tests with average error of -1.30%, while other methods of design gave significantly higher average errors. Furthermore, to evaluate the accuracy and predictability of each method, a statistical analysis was performed using four independent statistical criteria, namely: (1) the best-fit line with the corresponding coefficient of correlation, r(2), (2) the cumulative probability concept, (3) the 20% accuracy level derived from Log Normal distribution, and (4) the arithmetic mean (mu) and coefficient of variation (COV).
International Journal of Innovative Technology and Exploring Engineering, 2020
Corrugated metal pipes, fabricated from galvanized steel, are among the most common structures em... more Corrugated metal pipes, fabricated from galvanized steel, are among the most common structures employed to construct, culverts, underpasses, etc. in the world. Furthermore, the merits of this system over the traditional concrete structures are: lightweight structure, great strength relative to their mass, ease of transport and installation, and low cost. However, application of such construction system in Egypt is not commonly used yet, and many technical problems have been observed during and after construction. Consequently, this paper investigates the deformations around buried steel structures, axial forces and bending moments induced in structures due to back-filling and external loading. Furthermore, two case studies of buried steel projects have been presented in this paper. The first case study has been simulated using finite element method while the second one has been analyzed using analytical methods given in the literature and well-known codes of practice. Thus, an elabo...
This technical report presents a comparative study of the predictability of estimating the ultima... more This technical report presents a comparative study of the predictability of estimating the ultimate pile capacity between widely accepted international design codes of pile foundations, including the: Japan Road Association code (JPA, 2002), DIN 4014 (1990), Egyptian geotechnical design code-Part 4 (2001), and AASHTO (2007). The ultimate pile capacities inferred from the results of load-settlement test using the Chin extrapolation method (1970) were compared with the predicted values obtained from international codes of design. The study covers a wide range of Egyptian soil formations by utilizing 58 case studies of bored piles (loading tests) constructed and tested in numerous regions inside Egypt. The average error percentage obtained from each code of design has been calculated, and the predictability of these design codes has been evaluated based on four independent statistical criteria. JRA code (2002) and DIN 4014 (1990) have revealed well predictability and accuracy of estima...
The aim of this paper is essentially to investigate the influence of the following factors, namel... more The aim of this paper is essentially to investigate the influence of the following factors, namely slenderness of pile, loading frequency, and number of cycles on the behavior of pile foundations of wind turbines under lateral cyclic loading. Thus, an experimental study has been carried out using pile models founded into medium dense sandy soils, and two-way lateral cyclic loading displacement of several frequencies were applied on pile head. Experimental setup was explained in details, and results were presented in the form of cyclic load–displacement curves and normalized bending moment charts against the number of cycles. Besides, initial modulus of subgrade reaction and cyclic p–y curves were estimated. The results provide an insight into the key parameters controlling the performance of pile foundations under pure lateral cyclic loading conditions.
In this paper, a set of small-scale laboratory single flexible pile model was conducted in a medi... more In this paper, a set of small-scale laboratory single flexible pile model was conducted in a medium dense Toyoura sand environment under the effect of cyclic lateral loads. Digital images were captured for the plastic deformations of the soil during the lateral loading from the top of the testing chamber. Combination of photo image analysis and analytical cyclic p-y curve methods was implemented for estimating the three dimensional (3D) failure zone adjacent to pile shaft. The 3D failure pattern of the soil around single pile shaft was investigated through two steps, including: (1) determination of the range of lateral plastic deformations at the top of ground surface in perpendicular and parallel directions of cyclic loads; and (2) determination of the point of rotation (zero displacement) along the pile shaft. Experimental results showed that a conical passive zone of plastic deformations is established around pile shaft due to applying two-way lateral cyclic loading at pile head....
International Journal of Physical Modelling in Geotechnics, 2016
Journal of Al-Azhar University Engineering Sector, 2019
Slope-stability failures have occurred in several improper landfills and illegal dumping sites. T... more Slope-stability failures have occurred in several improper landfills and illegal dumping sites. To investigate the shear response of municipal solid waste (MSW), it is significant to consider the stability of dumping site and landfill design. In the present paper, the shear response and shear strength of MSW recovered from four different landfill sites (in Japan and China) were investigated using a developed in-situ direct shear test apparatus. Moreover, the paper introduces the steps for preparation of undisturbed samples and test procedures in details to determine the in-situ shear strength characteristics (c and φ) of MSW. The in-situ experimental results indicated that the shear response of waste materials affected by the existence of fibrous materials. In addition, the values of cohesion and friction parameters of waste materials strongly depended on the percent of fibrous materials. Results of geotechnical investigations and slope stability studies of landfill sites have been also introduced.
Innovative Infrastructure Solutions, Feb 7, 2022
Shear strength properties of fibrous waste materials, which are found in most of landfill sites, ... more Shear strength properties of fibrous waste materials, which are found in most of landfill sites, play a significant role in the stability of side slopes of those sites. Recent records revealed that slope failures have occurred in several improper dumping and illegal landfill sites at some countries. Therefore, this paper introduces field and numerical studies to assess the shear strength properties of fibrous waste materials at locations of some municipal solid waste (MSW) sites. In the present study, shear response and shear strength of waste materials obtained from four different landfill sites were investigated using an especial developed in situ direct shear test apparatus. Moreover, the paper introduces the steps for preparation of undisturbed samples and test procedures in details to determine the in situ shear strength characteristics ( c and φ ) of MSW. The field experimental results indicated that the shear response of waste materials affected by the existence of fibrous materials contents in the MSW materials. In addition, the values of cohesion and friction parameters of waste materials strongly depend on the percent of fibrous materials. Furthermore, based on the field test results, numerical methods have been implemented in this work (i.e., FEM and LEM) to evaluate safety factors of side slopes, lateral and vertical deformations which usually occur during shearing and external loads.
Innovative Infrastructure Solutions, 2022
This paper introduces an investigation using 3-D finite element method (FEM) and empirical method... more This paper introduces an investigation using 3-D finite element method (FEM) and empirical methods for prediction of pull-out resistance (skin friction) of ground anchors installed in soil, and soft rock formations are presented. Four full-scale ground anchor tests installed into different soils and rock types namely, clay, silty sand, and sandstone, were carried out. The tests were performed up to twice of working loads or failure loads so that the ultimate skin friction resistance for each soil/rock strata under the pull-out loads was estimated. Furthermore, an extensive site investigation campaign was performed to predict the in situ soil/rock characteristics. Field test setup and installation method of the full-scale ground anchors were presented in details. FEM (Plaxis 3D subroutine) was used to verify the results of the pull-out field tests. Besides, the measurements of the field tests were compared with the values of unit skin friction resistance given by the well-known codes of practice (AASHTO, and BS 8081) for design of ground anchorage. It was found that the proposed 3-D FEM and the adopted constitutive models provided good agreement with the field test results.
The International Conference on Civil and Architecture Engineering, 2012
Pile foundations supporting bridge piers, offshore platforms, and towers are required to resist n... more Pile foundations supporting bridge piers, offshore platforms, and towers are required to resist not only static loading but also cyclic or dynamic lateral loading resulted from winds, sea waves, or earthquake actions. Therefore, it is necessary to examine the effects of slow cyclic loads on the pile foundation behavior. This paper presents an experimental study on pile models of different arrangements founded in both dense and loose sands of relative densities equal to D r =75% and 35%, respectively. In this work, series of two-way lateral cyclic loading tests were performed on three pile arrangements (single, 3 ×1, and 3×3 groups) having length to diameter ratio (L/d) of 10 and 20 with spacing to diameter ratio (S/d) of 3. The experimental setup was explained in details and the results were presented in the form of cyclic load-deflection curves and normalizedbending moment charts against the number of cycles. Moreover, cyclic group efficiency, and cyclic p-multipliers were evaluated.
In this paper, a comparison study based on results of experimental lateral pile load tests was ca... more In this paper, a comparison study based on results of experimental lateral pile load tests was carried out between a new proposed method and widely used methods for predicting the ultimate lateral resistance of piles in sandy soil. The proposed technique agrees well with those obtained from the centrifuge tests with average error of -1.30%, while other methods of design gave significantly higher average errors. Furthermore, to evaluate the accuracy and predictability of each method, a statistical analysis was performed using four independent statistical criteria, namely: (1) the best-fit line with the corresponding coefficient of correlation, r(2), (2) the cumulative probability concept, (3) the 20% accuracy level derived from Log Normal distribution, and (4) the arithmetic mean (mu) and coefficient of variation (COV).
International Journal of Innovative Technology and Exploring Engineering, 2020
Corrugated metal pipes, fabricated from galvanized steel, are among the most common structures em... more Corrugated metal pipes, fabricated from galvanized steel, are among the most common structures employed to construct, culverts, underpasses, etc. in the world. Furthermore, the merits of this system over the traditional concrete structures are: lightweight structure, great strength relative to their mass, ease of transport and installation, and low cost. However, application of such construction system in Egypt is not commonly used yet, and many technical problems have been observed during and after construction. Consequently, this paper investigates the deformations around buried steel structures, axial forces and bending moments induced in structures due to back-filling and external loading. Furthermore, two case studies of buried steel projects have been presented in this paper. The first case study has been simulated using finite element method while the second one has been analyzed using analytical methods given in the literature and well-known codes of practice. Thus, an elabo...
This technical report presents a comparative study of the predictability of estimating the ultima... more This technical report presents a comparative study of the predictability of estimating the ultimate pile capacity between widely accepted international design codes of pile foundations, including the: Japan Road Association code (JPA, 2002), DIN 4014 (1990), Egyptian geotechnical design code-Part 4 (2001), and AASHTO (2007). The ultimate pile capacities inferred from the results of load-settlement test using the Chin extrapolation method (1970) were compared with the predicted values obtained from international codes of design. The study covers a wide range of Egyptian soil formations by utilizing 58 case studies of bored piles (loading tests) constructed and tested in numerous regions inside Egypt. The average error percentage obtained from each code of design has been calculated, and the predictability of these design codes has been evaluated based on four independent statistical criteria. JRA code (2002) and DIN 4014 (1990) have revealed well predictability and accuracy of estima...
The aim of this paper is essentially to investigate the influence of the following factors, namel... more The aim of this paper is essentially to investigate the influence of the following factors, namely slenderness of pile, loading frequency, and number of cycles on the behavior of pile foundations of wind turbines under lateral cyclic loading. Thus, an experimental study has been carried out using pile models founded into medium dense sandy soils, and two-way lateral cyclic loading displacement of several frequencies were applied on pile head. Experimental setup was explained in details, and results were presented in the form of cyclic load–displacement curves and normalized bending moment charts against the number of cycles. Besides, initial modulus of subgrade reaction and cyclic p–y curves were estimated. The results provide an insight into the key parameters controlling the performance of pile foundations under pure lateral cyclic loading conditions.
In this paper, a set of small-scale laboratory single flexible pile model was conducted in a medi... more In this paper, a set of small-scale laboratory single flexible pile model was conducted in a medium dense Toyoura sand environment under the effect of cyclic lateral loads. Digital images were captured for the plastic deformations of the soil during the lateral loading from the top of the testing chamber. Combination of photo image analysis and analytical cyclic p-y curve methods was implemented for estimating the three dimensional (3D) failure zone adjacent to pile shaft. The 3D failure pattern of the soil around single pile shaft was investigated through two steps, including: (1) determination of the range of lateral plastic deformations at the top of ground surface in perpendicular and parallel directions of cyclic loads; and (2) determination of the point of rotation (zero displacement) along the pile shaft. Experimental results showed that a conical passive zone of plastic deformations is established around pile shaft due to applying two-way lateral cyclic loading at pile head....
International Journal of Physical Modelling in Geotechnics, 2016