Performance-based analysis of Transit tunnels in the Chilean subduction zone
Date
2022
Type:
Article
item.page.extent
item.page.accessRights
item.contributor.advisor
ORCID:
Journal Title
Journal ISSN
Volume Title
Publisher
item.page.isbn
item.page.issn
item.page.issne
item.page.doiurl
item.page.other
item.page.references
Abstract
In this article, we study the seismic response of a shallow metro tunnel in a subduction zone environment and the use of a performance-based approach to develop seismic demand hazard curves (SDHC) of key engineering demand parameters, such as drift ratio, surface settlement, bending moment, and axial loads. The tunnel consists of a 6-m diameter sprayed concrete lining in medium dense soil and is located in Santiago, Chile. To simulate its seismic response, a finite element model of the soil–tunnel system was implemented in OpenSees and validated against centrifuge test results, linear-equivalent solutions for a 1D soil column, and single elements in cyclic simple shear. The tunnel response was computed for 112 ground motions, selected and scaled using the conditional scenario approach. This approach assigns a rate of occurrence to each ground motion and therefore, allows for a direct computation of annual exceedance rates of the tunnel response parameters. For instance, at this specific location, the 2500-yr return period drift ratio in the lining is approximately 0.25% as a result of large deformations imposed by the surrounding soil. Likewise, axial loads between 0.3 and 1.0 MN/m and vending moments of ±0.2 MN∙m/m are apparent from the axial load-moment interaction diagrams; these results are of great value for the design and verification of the tunnel based on the collapse or life-safety limit states. Notably, the current formulation relaxes the assumption of scaling ground motions to a particular intensity measure and can be a computationally efficient alternative to standard incremental dynamic analyses
Description
item.page.coverage.spatial
item.page.sponsorship
Citation
Benjamín Lyon, Gabriel Candia, Carlos Gutiérrez, Jorge Macedo, Performance-based analysis of Transit tunnels in the Chilean subduction zone, Soil Dynamics and Earthquake Engineering, Volume 152, 2022, 107047
Keywords
Shallow tunnels, Earthquakes, Subduction, Seismic hazard, Conditional scenario, Centrifuge experiments, Finite elements