Analysis of Seismic Stability of Quay Walls

Abstract

The earthquake induced pressures and seismic stability of Quay walls is investigated. The study was motivated by lack of suitable earthquake stability analysis of Quay wall considering all the forces acting on the wall under a dynamic load.

Pressures and Forces on the walls for a number of idealized conditions are analyzed. The earth pressures are obtained using different approaches namely, Limit state methods, Elasto-Dynamic methods and SSI framework. Using these pressures, the stability of the wall is analyzed and compared for various failure modes viz. Sliding, Overturning and Bearing capacity failures.

The critical nature of the Bearing capacity failure mode is emphasized. A thorough analysis is conducted to examine factor of safety for bearing capacity failure, particularly in the presence of seismic forces. Various scenarios are explored, such as inclined base conditions, variations in wall structure (hollow vs. rigid), wider base block etc. with a comprehensive examination of how different variables impact the outcomes.

It was found that the inertia of the wall usually exceeds active thrust for kh equal to 0.1-0.15 and becomes dominating force destabilizing the wall and the wall's stability is significantly undermined by its inertia especially in the case of sliding. The safety factor reduces by 25-30% for every increment of 0.1 in kh and the aspect ratio requirement to satisfy the safety criteria increases by 20% respectively. The use of a configuration with hollow blocks, a tilted base, and a wider base block increases the stability of the wall by 20-50% against different modes of failure.

Last but not the least the optimum widths of the walls were obtained by varying different parameters and their variations is also presented.

Date of Award	19 Dec 2023
Original language	American English
Supervisor	GEORGE Mylonakis (Supervisor)