A study on problems associated with finite element excavation analysis by the stress-flow coupled method

This study attempts to address some problems associated with excavation ana lysis by means of the stress-flow coupled method. This is done through the investigation of two examples, both of which are excavation analyses modell ing a sequential excavation process. The first example is a three-dimension al elastic analysis of a tunnel constructed in soft rock layer. The second example is an axi-symmetric elasto-plastic analysis of a shaft constructed in slightly overconsolidated clay layer. In order to clarify the effect of sequential excavation process on the analysis results, a conventional two-d imensional analysis on each example is also carried out. Through this study , we will demonstrate that it is essential to consider in detail the increm ental advance of a tunnel face when one investigates the change of pore wat er pressure and stresses surrounding a tunnel face during excavation. Addit ionally, on the basis of the analytical results obtained, a proposal is pre sented for evaluating the stability of rock mass surrounding a tunnel durin g construction. Copyright (C) 1999 John Wiley & Sons, Ltd.