Second fine inversion of regional in-situ stress field considering the excavation disturbance effects of pilot tunnel

摘要

The changes of in-situ stress magnitude and directions caused by the excavation disturbance effect of pilot tunnel are usually neglected. An inversion regression method called region second fine in-situ stress field is proposed. Firstly, the surrrouding stress field of pilot tunnel was inversed finely by multiple linear regression inversion anlaysis in the local mesh model. In order to obtain the entire stress distribution of damsite region, the inversion analysis method of second stress field for the whole damsite region was presented, which combined the ground abrasion process of strata and support vector machine model. Considering the abrasion process of the strata, the second stress value of measuring points is calculated in the entire mesh model. Numerial results of real project indicate that the in-situ stress field obtained by second fine inversion method fits for the distribution law of V-shaped vally generally.