Numerical Reliability Analysis of Tunnel Face Stability with Interval and Fuzzy Soil Parameters

摘要

In the paper, an approach for numerical reliability analysis for the safety assessment in mechanized tunneling is presented.The tunnel face stability is numerically predicted with a 3D finite element model considering all relevant parameters of the excavation and construction process.Possible collapse mechanisms, e.g.the shear failure of the soil, are computed to assess the face stability and the level of safety during tunneling.Within the presented approach, the Shear Strength Reduction technique associated with an error based re-meshing strategy is employed assuming a Mohr-Coulomb failure criterion.Uncertain soil parameters are considered as intervals and fuzzy numbers, which are quantified based on the geotechnical reports prepared in the design stage of tunneling projects.Interval and fuzzy finite dement analyses in combination with a neural network based surrogate model are applied to compute the tunnel face stability for varying levels of the face support pressure.The resulting dependency between the face support pressure and the interval or fuzzy safety factors can be used to support the steering of mechanized tunneling machines in real-time.