ABSTRACT
This chapter addresses a parameter estimation technique to be applied in tunnelling. The extended Bayesian method (EBM) is adopted, which can systematically combine field measurements and prior information of underground structures in order to obtain the best estimate of geotechnical parameters. For the EBM, the relative importance of prior information over field measurements is defined by the parameter, ~. which is determined from the sensitivity of geotechnical parameters and the uncertainty existing in the prior information and the measurements. In the present study were various geotechnical parameters were determined, including the elastic modulus {E), the initial horizontal stress coefficient (KJ, the cohesion (c) and the internal frictional angle (cp). The validity of the feedback system proposed herein was demonstrated through an elasto-plastic example problem. The proposed method was applied to an actual tunnel site in Pusan, Korea and has shown to be highly effective in actual field problems.
