TBM performance prediction model with a linear base function and adjustment factors obtained from rock cutting and indentation tests

Abstract

A new TBM performance prediction model consisting of a basic penetration function and adjustment factors for different boundary conditions is presented. The basic penetration function is implemented as a linear function with an offset from zero based on Frenzel et al. (2012). Adjustment factors are used to refine the model which reflects the model architecture used by Gehring (1995). The well-established CSM model (Rostami, 1997) was used as a reference to account for tool geometry and spacing. In addition, a new approach to account for rock brittleness is presented based on the rock mechanical interpretation of Punch penetration tests (PPT). The proposed new model was developed using full scale linear rock cutting tests from 19 igneous, metamorphic, sedimentary and artificial rock types. It was validated with 36 TBM penetration tests from tunnels in the Swiss Alps (Villeneuve, 2017), Koralm tunnel and Røssåga tunnel (Wilfing, 2016). It has a strong predictive capability for a wide range of rock and rock mass parameters. The main strengths of the model are high accuracy, simplicity of the basic penetration function and the highly transparent development process that enables a clear understanding of its strengths and limitations.