Damages of Highway Tunnels During 2022 Luding Earthquake (Mw = 6.6)

Abstract

On 5 September 2022, an Mw = 6.6 magnitude earthquake hit the Luding area, Sichuan province, China, leading to 93 deaths, 25 disappearances, and great economic loss. The earthquake caused a series of geologic hazards and severe damage to infrastructures, such as tunnels, bridges, houses, roads, etc. In this study, a field survey was conducted for the twin tunnels along the Luding-Shimian highway after the earthquake. The highway was close to the epicenter, which was built along the Daduhe fault. Comprehensive data on tunnels on the highway was collected, such as damage characteristics, geological conditions, the situation behind the tunnels, design documents, etc. The field investigation found that three tunnels were damaged due to seismic shaking. Tunnel damages, such as cracks, spalling, and leakage, were observed. Based on the compiled data, a preliminary analysis was performed for the possible damage mechanisms of the tunnels. The damages were related to landslide mass, fractured zone, invert setup, and direction of tunnel alignment.

Keywords: Luding earthquake, mountain tunnel, highway, field investigation, preliminary analysis