Deformation Characteristics of Deep Excavation Supported by Contiguous pile wall On Soils Commonly Found in Addis Ababa
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Date
2017-11
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Addis Ababa University
Abstract
A two dimensional Finite Element (2D FE) study is carried out in this thesis, considering
soil-structure interaction. This thesis presents a study of the effects of deep excavations
supported by tie-back anchored contiguous pile wall, which is constructed at the center of
Addis Ababa and analyzed on three types of soil.
The objectives of this study is to investigate a deformation characteristic of deep excavation
to study the effect of the stiffness of the supporting system and stiffness of the supported
soils, with different drainage conditions, and to understand the performance of deep
excavations from the point of view of the effects on the already existing neighboring
structures load types. This analysis monitors the following parameters: maximum lateral
wall deflection, maximum settlement, angular deformation of the neighboring structures,
lateral movements of the structure corner and maximum bending moment in the retaining
wall. Moreover, following the normalization of lateral wall deflection and settlement with
the excavation depth, the relationship between the lateral wall deflection (
hm
) & settlement
(
vm
) and the distance excavation-neighboring structures are observed in graph and
expressed by exponential decay function equation in order to get preliminary contiguous
pile wall and soil parameters for design. Furthermore, this research also analyzes the
influence of structures load and soil types on its admissible deformation compared with
previous studies.
Parametric studies have been carried out to identify important variables controlling the
mechanisms and design of soil-structure interaction. The parameters considered in the study
include; soil type, diameter of contiguous pile wall (wall stiffness), strut (tie-back anchor)
spacing and strut (tie-back anchor) pre-stress force. Results of these analyses have recorded
in terms of lateral wall deflection, ground settlement and bending moments induced in
contiguous pile wall. Finally, the main accomplishments of the thesis and the corresponding
conclusions are summarized & recommendations are also made for further design of deep
excavation support systems.
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Keywords
Deep excavation, excavation support system, ontiguous pile wall, Finite Element Method, ground deformation