Estimation of radial deformations around circular tunnels in weak rock masses through numerical modelling

Sakcali A., Yavuz H.

INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES, vol.123, 2019 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 123
  • Publication Date: 2019
  • Doi Number: 10.1016/j.ijrmms.2019.104092


Tunnelling applications are increasing day by day due to challenging topographic conditions. During tunnel excavation, the primary stresses caused mainly by the overlying weight of rock mass together with the geological factors are replaced by secondary stresses. Thus, tunnel deformations occur around the face but also at and beyond the face in the longitudinal direction as this is truly 3D phenomenon. Determination of deformations behind the advancing face is very important for the design of support systems in tunnel engineering. The researchers emphasized that deformations around the circular tunnels depend on the distance to the face and recommended different equations to construct longitudinal deformation profiles (LDP). In this paper, circular tunnels excavated in weak rock masses with a total of 162 different conditions comprising material properties, tunnel dimensions and depth of cover were modelled by using finite difference method. The data obtained from the models were normalised with different parameters and statistical tests were performed. The equations and response surfaces of maximum and tunnel face deformation for different depths were suggested for weak rock masses. Therewithal, a prediction equation of longitudinal deformation profile (LDP) for weak rock masses was proposed. Assessment of radial deformations around a circular tunnel is possible by using these equations. The suggested equations were verified by means of analysis of variance and previous equations recommended by different researchers.