SIMPLE ANALYTICAL METHOD OF GROUND MOVEMENT DURING TUNNEL EXCAVATION

Abstract

This paper presents a simple method to analyze the measured results of tunnel wall convergence and of displacement in the surrounding ground during tunnel excavation. This method is based on the assumptions that a circular tunnel is excavated in a two-dimensional ideal elastic body and that the vertical stress is equal to the overburden pressure. We can estimate easily (1) the directions and values of the principal genuine mountain stresses and (2) the elastic shear modulus of the ground from tunnel convergence measurements. In addition to the above (1) and (2), (3) the absolute movement of surrounding ground and (4) the approximate extent of the inelastic zone caused in surrounding ground can be estimated also in the case of the extensometer measurements.