Estimation of initial stress based on the convergence measurement result during tunnel excavation

Kamemura, Katsumi*; Fujita, Tomoo ; Aoyagi, Kazuhei  ; Nago, Makito*; Shirase, Mitsuyasu*; Sugawara, Kentaro*

How to estimate the initial stress state as well as a mechanical characteristic of rock mass is important in the design of deep underground structures. Some stress measurement methods using borehole, which methodology and evaluation method have been discussed in detail, are carried out if necessary. However, obtained results are often varying widely, so the evaluation of initial stress is difficult. Here, the initial stress state corresponding to the rock mass behavior of about 120m200m area is evaluated using the convergence measurement results during tunnel excavation in 350m depth. Analysed result corresponded to that of other method, so the validity of the proposed method was shown.