Tunnel performance during the Puebla-Mexico 19 September 2017 earthquake

Abstract

Seismic performance of tunnels during earthquakes in densely populated areas requires assessing complex interactions with existing infrastructure such as bridges, urban overpasses, and metro stations, including low- to medium-rise buildings. This article presents the numerical study of an instrumented tunnel, currently under construction on stiff soils, located in the western part of Mexico City, during the Puebla-Mexico 19 September 2017 earthquake. Three-dimensional finite difference models were developed using the software FLAC3D. Initially, the static response of the tunnel was evaluated accounting for the excavation technique. Then, the seismic performance evaluation of the tunnel was carried out, computing ground deformations and factors of safety, considering soil nonlinearities. Good agreement was observed between predicted and observed damage during post-event site observations. Once the soundness of the numerical model was established, a numerical study was undertaken to investigate the effect of frequency content in tunnel-induced ground motion incoherence for tunnels built in cemented stiff soils. A series of strong ground motions recorded during normal and subduction events were used in the simulations, considering a return period of 250 years, as recommended in the Mexico City building code. From the results, it was concluded that the tunnel presence leads to important frequency content modification in the tunnel surroundings which can affect low- to mid-rise stiff structures located nearby. This important finding must be taken into account when assessing the seismic risk in highly populated urban areas, such as Mexico City.

Investigation of the support constraint effect and failure instability law of tunnels constructed using the New Austrian tunneling method

“…Berkane et al 14 analyzed the failure law of the T1 tunnel of the Algerian East-West Highway under the influence of seismic waves by numerical calculation method. Mayoral et al 15 used numerical methods to study the stability of the tunnel during Puebla-Mexico earthquakes. Taking the diversion tunnel in Sri Lanka as the engineering background, Golian et al 16 studied the influence of underground water on tunnel stability through numerical calculation method.…”