Internal and External Collapse Analysis of Twin-Tubes Tunnel in the Initial Support Stage

Abstract

The characterization of rock mass along the tunnel alignment based on physical, geological and geotechnical data of the project area was used in this work. The support systems were recommended for all geotechnical units using RMR and tunneling quality index (Q-system) support chart. The paper also consists in making a two-dimensional numerical study of the stability of the left lateral slope of the Portal of the tunnel with the Slide 6.0 software and inside provisional support with the Phase.2 2D program. The study shows good results of the internal rock mass stability of the tunnel and satisfactory safety factor (FoS) in terms of collapse analyzes of the lateral slope of the tunnel portals.