How is the deformation at the tunnel face calculated in RocSupport?

In RocSupport for deformation at the tunnel face, two values are reported: wall displacement and tunnel convergence.  The following two references are the basis for the deformation calculations:

Carranza-Torres, C. (2004). Elasto-plastic solution of tunnel problems using the generalized form of the Hoek–Brown failure criterion. International Journal of Rock Mechanics and Mining Sciences, Proceedings of the ISRM SINOROCK 2004 Symposium, edited by J.A. Hudson and Xia-Ting Feng, Volume 41, Issue 3.

 

Duncan Fama, M. E. (1993). Numerical Modeling of Yield Zones in Weak Rock. In: Hudson JA, editor. Comprehensive Rock Engineering, 2. Oxford: Pergamon, 1993. p. 49-75