GEOTECHNICAL, GEOPHYSICAL INVESTIGATIONS AND SEISMIC RESPONSE ANALYSIS OF THE UNDERGROUND TOMBS IN MUSTAFA KAMIL NECROPOLIS, ALEXANDRIA, EGYPT

Abstract

The paper presents the geotechnical, geophysical investigations and the numerical stat-
ic and seismic analysis of selected underground monuments in Alexandria, Egypt i.e. the
underground tombs in Mustafa Kamil Necropolis. The analysis of the static stability and
the behavior of complex monuments of this kind under seismic loading, are the key fac-
tors for the efficient restoration and retrofitting of these underground monumental struc-
tures.
In the present paper, we present in a first phase a comprehensible geotechnical survey
undertaken in this site, comprising geophysical ambient noise measurements (micro-
tremors), as well as field and short – long-term laboratory experiments and tests, in order
to define the physical, mechanical and dynamic properties of the soils and soft rock mate-
rials. In the second stage, we present the main results of the detailed static and seismic
numerical analysis of these underground monumental structures (Catacombs) using the
code, PLAXIS b.v with different seismic scenarios corresponding to the seismotectonic
features of Alexandria. Advanced soil-rock elastoplastic modeling has been used through
out the different phases of the numerical finite element analysis.
The aim of the analysis is twofold: (a) to investigate the safety margins of the existing
monuments, under their present conditions, against environmental (i.e. weathering) and
extreme seismic loads and (b) to investigate the potential improvement of their global
behavior applying specific retrofitting techniques.