Application of Hyperstatic Reaction Method for Designing of Tunnel Permanent Lining, Part II: 3D Numerical Modelling
Abstract: Underground
structures often have abrupt changes in structural stiffness or ground
conditions such as junctions of tunnels, tunnel portal in slopes, and niches in
road tunnels. At these locations, stiffness differences may subject the
structure to differential movements and generate stress concentrations. Because
of adversity in these issues, they need a three dimensional analysis. This
paper proposes a numerical approach to the hyperstatic reaction method (HRM)
for three dimensional analysis of permanent tunnel linings. In this paper,
three dimensional numerical modelling is performed by considering hyperstatic
reaction concepts. Designing is done for Manjil-Rudabar freeway project, Tunnel
No. 2. The numerical analyses performed for Operational Design Earthquake (ODE)
and Maximum Design Earthquake (MDE) loading conditions. Then interaction
diagram between axial force and bending moment used for investigating the capacity
of tunnel lining. The numerical results show that although more axial forces
are created in tunnel lining for ODE condition, but the points in the P-M
diagrams are located in the furthest distance to the diagram border (tunnel
supporting system); because of less bending moment in this condition.
Therefore, the safety factor in ODE condition is more than MDE condition. This
numerical processing presented that the HRM is a proper, fast, and practical
method for tunnel designers.
Keywords: Hyperstatic Method;
Tunnel Lining; 3D Numerical Modeling; Static Analysis; Dynamic Analysis
Author: Rahim Hassani,
Rouhollah Basirat
Journal Code: jptsipilgg160033
