Analysis and Parametric Study of Tangent Pile Wall as Deep Excavation Support System Using Finite Element Based Software

Abstract

The need for deep excavations become increasing in urban areas to have underground spaces. Addis Ababa is a fast growing city in number and types of construction activities. The excavations for multi-story buildings and, new and maintenance of old roads are currently in the city. As most of these excavations are very deep as involved by current constructions, a support system is necessary for protecting soil movement and adjacent structures. Hence, accurate predictions of lateral wall deflections and ground surface settlement are important design criteria in the analysis and design of excavation support systems. The purpose of this study is to analyze tangent pile wall as deep excavation support system on silty-clay soil. A parametric study was conducted by varying the adjacent surface load, equivalent thickness (diameter) of pile wall and strut horizontal spacing for different excavation heights. PLAXIS 3D was used as a tool to carry out all the analysis of parameters. The analysis resulted in the horizontal displacements of the wall, ground surface settlement behind the wall and bending moments induced in the pile wall. The change in the adjacent surface load and equivalent wall thickness showed the greatest effect on the result. The normalized allowable deformation values from literatures have been compared with the cases with normalized deformation values. The comparison indicated that the vertical deformation fall in between 0.5 to 1.0 times the maximum horizontal displacement. This study definitely answers the questions about the analysis and parametric study of tangent pile wall as deep excavation support system and the effect of change in adjacent surface load, equivalent thickness and strut horizontal spacing. Key