ABSTRACT
For the in-situ stress field, the back analysis methods can be divided into two categories. In the first approach, known as the multiple regression analysis of the in-situ stress field, the back analysis requires a small number of measured values of the in-situ stress field. Results from the multiple regression analysis of these measurements are then fed into a three-dimensional finite element model to determine the in-situ stress field (Kavanagh and Clough, 1972; Brady and Brown, 1985). In the second approach, known as the displacement back analysis method, the back analysis of the initial stresses field is based on the monitored displacement field. For general underground engineering excavation in rock masses, a measuring system for displacements is usually established to ensure the safety of the construction, and the displacements in the surrounding rock can be used in the back analysis of rock mass mechanical parameters (Kaiser et al., 1990; Swoboda et al., 1999; Yang et al., 2001). For this reason, it is not always necessary to establish an extra measuring system for the back analysis.
