Application of Convergence - Confinement Method in Analysis for Longitudinal Displacements in Tunnel
Singgih Saptono, M Rahman Yulianto, Vega Vergiagara

Mining Department, Faculty Technology Mineral
Universitas Pembangunan Nasional Veteran Yogyakarta
Jalan Pajajaran 104, Condongcatur, Sleman
Yogyakarta, 55283, Indonesia

Abstract

The application of convergence-confinement analysis for tunnel is preliminary analysis standard method for determining tunnel walls displacements and designing support systems for rocks.
Furthermore, this convergence-confinement analysis uses an analytical solution (closed form) or with a plane strain numerical model (FEM), a longitudinal displacement profile (LDP) is needed to relate the displacement of the wall tunnel at the excavation stage analyzed in the physical opening along the opening axis.
This paper is an application of the LDP formulation developed by Vlachopoulos and Deiderichs (2009) to estimate the influence of the supported distance from the face (working surface) of the tunnel, the spacing between rock bolts diametrically and transversely on the safety factor, as well as the maximum plastic radius that occurs during installation. The parameters used to calculate with assumption the ideal condition changes according to changes in the size of the plastic zone area. Larger plastic zones require relatively longer normal distances to be excavated.
Failures in LDP implementation can result in significant errors in the proper positioning of support installation distances (from the face) for tunnel support systems. Examples of errors include the collapse of temporary supports.

Keywords: Tunnel, convergence-confinement, displacement

Topic: Mining Engineering and metallurgy