الفهرس 
General Earth Retaining SystemsOnly 14 pages are availabe for public view
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Abstract
In urban environments, temporary Excavation Support Systems (ESSs) are
intensively recommended during the construction process of structures with
underground levels to preserve nearby structures and maintain the excavation sides. Once the foundations and basements are constructed, these systems are rendered useless. As a result, integrating the temporary ESS into the building foundation may have significant benefits. The utilization of an ESS as a foundation element could decrease the required materials for foundation construction, and the construction time
as well as limit the reduction in the building footprint. Moreover, Secant Pile Wall (SPW) is a popular type of excavation support system in urban areas. Overall, there is a shortfall of laboratory testing studies on the behavior of RC secant pile walls under lateral and axial loads. Therefore, the main aim of this thesis was to achieve both experimental and numerical perspectives on the overall behavior of axially loaded RC secant pile walls, with an acceptable scale, embedded in the dense and medium sand. This study considered several factors to define wall behavior, such as normalized horizontal deflection (δh/Ht%), the vertical deflection of the SPW (δvw/Ht%), the vertical ground settlement (δv/Ht%), and settlement influence zone (Do). These factors were investigated and analyzed under the influence of a set of parameters including normalized penetration depth (He/Hc), sand relative density (Dr), wall rigidity (Ht/Dp), and surcharge load intensity (Wsur). Also, the structural performance of the examined models was evaluated using two types of tests (bending and axial compression). A self-compacting concrete mix has been suggested, which provides the best concrete mix workability and appropriate compressive strength. Also, a finite element model (FEM) using the commercial software PLAXIS 2-D was proposed to analyze and predict the behavior of axially loaded SPWS based on the experimental results. The experimental findings demonstrated that the proposed SPWs had structural and overall stability features to withstand lateral earth pressures as well as applied axial loads. Generally, increasing the He/Hc ratio further than a limit value of 2.0 for the same surcharge load had a limited impact on the ultimate axial capacity, particularly in the case of dense sand. The location of the pivot point (ε’) extended from 0.24 He to 0.41 He from the wall tip, with a mean value of 0.34 He and 0.29 He for the values of Dr = (80±2) %, and (60±2) %, respectively. Other issues were also discussed for selected samples, including an analysis of the wall’s bending moments and any potential wall buckling. Also, to correlate the experimental data with the theoretical values, a modification factor for the pile static formula was developed by using nonlinear regression analysis with a significant prediction accuracy with R2 of 0.94. Also, the proposed FEM can simulate the behavior of the model tests with fair accuracy under the effect of the axial and lateral loads. Additionally, a parametric analysis with 224 tests on axially loaded SPWs was conducted, primarily to ascertain the impact of different parameters on the ultimate axial capacity of the SPW (Pult). By using statistical analysis, the data from the parametric analysis was utilized to create rational relations between the various parameters. The best achieved mathematical models were also represented in graphical forms. Moreover, these graphs can be a useful and fast tool for civil and geotechnical engineers to predict the ultimate axial capacity of an SPW according to the different variables.