A numerical study on squeezing of overstressed rock around deep tunnels

Abstract

Squeezing is a phenomenon that may occur in deep tunneling and could bring about a large plastic deformation, tunnel closure and collapse of tunnel supports. Therefore, quantitative estimations of deformation and stress from squeezing and its possibility are necessary for establishment of a rational tunneling method. This study carried out three dimensional numerical analyses using a strain softening model in order to simulate the behaviour of squeezing and to estimate deformation and yield area around tunnels quantitatively. Numerical analyses were performed for 42 cases of various stress and strength conditions. As a result, the maximum tangential stress and strength of rock mass ratio could estimate plastic deformation and yield depth around tunnels and equations of relations between them were proposed.

Reliability and Efficiency of Metamodel for Numerical Back Analysis of Tunnel Excavation

“…Finally, the remaining five factors except D were selected as the dependent variables. Similarly to this selection, Lee [17] had selected tunnel depth, UCS, GSI, m i , and K as dependent variables to evaluate the behaviour of rock masses at a deep depth. Except for tunnel depth, four factors are the same as the selected dependent variables in this study.…”