18 Abstract— In this paper, the ground surface settlements due to construction of tunnels by slur... more 18 Abstract— In this paper, the ground surface settlements due to construction of tunnels by slurry shield tunnel boring Machine are predicted. The construction stages and parameters such as excavation, face and grouting pressures, jacking forces, etc. are simulated in a three dimensional finite elements analysis utilizing MIDAS software. The main objective is to simulate the conditions of a section along the route of the Greater Metro Line 3 Phase 1 and to compare the results with the actual settlement monitored during construction of the Project. The results of the maximum ground surface settlement show that numerical results are about 3.5 times the actual measured values. Results from sensitivity analyses for all parameters show that both the face and grout pressures are the most influencing parameters. Changing the values of face pressure results in considerable change in the values of the surface settlement as compared to changing the grout pressure. However, it is confirmed th...
Expansive soils shrink and swell with drying and wetting cycles. The shrink-swell capacity of exp... more Expansive soils shrink and swell with drying and wetting cycles. The shrink-swell capacity of expansive soils can result in differential movement beneath foundations which is a very common cause of foundation problems. Ribbed slab, often called waffle slab, is one of the efficient and inexpensive foundation solutions for use under light structures resting on shrink-swell soils. This paper presents a numerical analysis that is used to calculate displacement and internal forces in ribbed slab foundations resting on swell/shrink soil. The stiffness of the ribbed slab is modelled as an equivalent flat slab of constant thickness and the straining actions are calculated for the case of central heave. A parametric study of the effect of beam dimensions and rib spacing is performed to assess the optimum configuration. Dimensioning of the waffle slab system; slab thickness, depth and width of beams and spacing, is performed according to the Egyptian Code of Practice for the design of concret...
The increased terrorist attacks on important public structures and utilities have raised the vita... more The increased terrorist attacks on important public structures and utilities have raised the vital necessity for the investigation of performance of structures under blast loads to improve the design and enhance the behavior of structures subjected to such threats. In this study, 3-D finite element analysis is used to study the effect of surface explosions on the response of RC bored tunnels. The soil behavior is modelled using Drucker-Prager Cap model. Two types of soil are investigated, and the blast load is considered through various weights of TNT explosive charges at heights of 0.50 m and 1.0 m from ground surface. To study the effect of horizontal standoff distance, six different horizontal distances are considered. The results show that the soil type has a significance effect on tunnel response due to surface blasts. Also the weight and the location of charge have a great effect on the safety of the tunnel. Finally, a parametric study is established to define the borders of th...
Journal of Environmental and Engineering Geophysics, 2001
Spectral-Analysis-of-Surface-Waves (SASW) testing was conducted in untreated and treated drilled ... more Spectral-Analysis-of-Surface-Waves (SASW) testing was conducted in untreated and treated drilled shafts at the NGES “TXHOUSTO” test site as part of a study on lime-slurry conditioning of soil in drilled shafts for pier foundation construction. Results of SASW testing in an untreated shaft revealed a reduction in shear wave velocity ([Formula: see text]; a measure of small-strain shear stiffness) within an annular zone slightly less than one shaft diameter in thickness. This reduction is attributed to stress relief and soil disturbance during excavation. Results of SASW testing in a treated shaft revealed that [Formula: see text] of the soil surrounding the shaft depended upon whether the measurement was performed above or below the water table. Above the water table, a thin (less than [Formula: see text]) annulus of stiffen cemented soil was created due to the reaction between the lime and the carbon dioxide in the pore spaces of the partially saturated soil. Since the clay was satu...
18 Abstract— In this paper, the ground surface settlements due to construction of tunnels by slur... more 18 Abstract— In this paper, the ground surface settlements due to construction of tunnels by slurry shield tunnel boring Machine are predicted. The construction stages and parameters such as excavation, face and grouting pressures, jacking forces, etc. are simulated in a three dimensional finite elements analysis utilizing MIDAS software. The main objective is to simulate the conditions of a section along the route of the Greater Metro Line 3 Phase 1 and to compare the results with the actual settlement monitored during construction of the Project. The results of the maximum ground surface settlement show that numerical results are about 3.5 times the actual measured values. Results from sensitivity analyses for all parameters show that both the face and grout pressures are the most influencing parameters. Changing the values of face pressure results in considerable change in the values of the surface settlement as compared to changing the grout pressure. However, it is confirmed th...
Expansive soils shrink and swell with drying and wetting cycles. The shrink-swell capacity of exp... more Expansive soils shrink and swell with drying and wetting cycles. The shrink-swell capacity of expansive soils can result in differential movement beneath foundations which is a very common cause of foundation problems. Ribbed slab, often called waffle slab, is one of the efficient and inexpensive foundation solutions for use under light structures resting on shrink-swell soils. This paper presents a numerical analysis that is used to calculate displacement and internal forces in ribbed slab foundations resting on swell/shrink soil. The stiffness of the ribbed slab is modelled as an equivalent flat slab of constant thickness and the straining actions are calculated for the case of central heave. A parametric study of the effect of beam dimensions and rib spacing is performed to assess the optimum configuration. Dimensioning of the waffle slab system; slab thickness, depth and width of beams and spacing, is performed according to the Egyptian Code of Practice for the design of concret...
The increased terrorist attacks on important public structures and utilities have raised the vita... more The increased terrorist attacks on important public structures and utilities have raised the vital necessity for the investigation of performance of structures under blast loads to improve the design and enhance the behavior of structures subjected to such threats. In this study, 3-D finite element analysis is used to study the effect of surface explosions on the response of RC bored tunnels. The soil behavior is modelled using Drucker-Prager Cap model. Two types of soil are investigated, and the blast load is considered through various weights of TNT explosive charges at heights of 0.50 m and 1.0 m from ground surface. To study the effect of horizontal standoff distance, six different horizontal distances are considered. The results show that the soil type has a significance effect on tunnel response due to surface blasts. Also the weight and the location of charge have a great effect on the safety of the tunnel. Finally, a parametric study is established to define the borders of th...
Journal of Environmental and Engineering Geophysics, 2001
Spectral-Analysis-of-Surface-Waves (SASW) testing was conducted in untreated and treated drilled ... more Spectral-Analysis-of-Surface-Waves (SASW) testing was conducted in untreated and treated drilled shafts at the NGES “TXHOUSTO” test site as part of a study on lime-slurry conditioning of soil in drilled shafts for pier foundation construction. Results of SASW testing in an untreated shaft revealed a reduction in shear wave velocity ([Formula: see text]; a measure of small-strain shear stiffness) within an annular zone slightly less than one shaft diameter in thickness. This reduction is attributed to stress relief and soil disturbance during excavation. Results of SASW testing in a treated shaft revealed that [Formula: see text] of the soil surrounding the shaft depended upon whether the measurement was performed above or below the water table. Above the water table, a thin (less than [Formula: see text]) annulus of stiffen cemented soil was created due to the reaction between the lime and the carbon dioxide in the pore spaces of the partially saturated soil. Since the clay was satu...
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