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A concise presentation of the project's aim and main outcomes is available in the Joint brochure of the SERIES TA facilities.

TITLE OF PROPOSAL: Investigation of several aspects affecting the seismic behaviour of shallow rectangular underground structures in soft soils

HOST TA FACILITY: Turner Beam Centrifuge, Cambridge, UK

TA AGREEMENT BETWEEN USERS AND FACILITY: 1 September 2011

STARTING DATE: October 2011

END DATE: June 2012

NO. OF USERS (researchers): 5

LEAD USER: 
Kyriazis Pitilakis - AUTH: Aristotle University of Thessaloniki (Greece)

ADDITIONAL USERS: 
Grigorios Tsinidis - AUTH: Aristotle University of Thessaloniki (Greece)
Anastasios Anastasiadis - AUTH: Aristotle University of Thessaloniki (Greece)
Dimitrios Pitilakis - AUTH: Aristotle University of Thessaloniki (Greece)
Roberto Paolucci - Politecnico di Milano (Italy)

SUMMARY OF PROPOSED RESEARCH:

Extended underground structures such as tunnels, metro and parking stations or other large underground facilities constitute crucial components of the transportation network and the built environment in urban areas and Megacities. Τhe important socio - economic nature of these structures and the associated impact in case of earthquake induced damage denote the paramount importance of safe seismic design, especially in seismic prone regions.

Considering the specific geometrical and conceptual features of these types of structures, that makes their seismic behaviour very distinct from aboveground structures and the lack of well-documented case histories regarding their seismic performance, their seismic design becomes a very demanding procedure. The lack of knowledge on many crucial issues is reflected on the lack of guidelines and specific seismic code regulations regarding the seismic design of this kind of structures.

To this end, two research projects (“Centrifuge modeling of dynamic behavior of box shaped underground structures in sand” – DRESBUS I and “Investigation of the seismic behaviour of shallow rectangular underground structures in soft soils using centrifuge experiments” – DRESBUS II) are going on within the framework of SERIES Transnational Access program, aiming to provide specific answers to several crucial issues related with the seismic behavior and design of underground structures.

The research proposal presented herein is complementary to these ongoing projects. In particular it is proposed to perform well – focused centrifuge tests to investigate the following critical points: 

(i) Influence of the relative flexibility ratios (ratio of the underground structure to soil ground flexibility) on the dynamic response of flexible underground structures, to the drift displacement.

(ii) Investigation of the seismic earth pressures and the seismic shear stresses distribution developed during shaking along the perimeter of an underground structure.

(iii) Investigation of the distribution of the lining forces developed during shaking.

The production of high quality experimental data as in centrifuge testing will be valuable in order to better understand the seismic behaviour of underground structures and to validate numerical models.