抄録
This paper deals with some problems encountered in the back analysis of measured displacements carried out during the excavation of tunnels in order to monitor their stability.
The paper consists of two parts. The first part deals with the problems that arise when the displacements have already taken place before the measuring devices are installed and the first reading is taken. Hence, the results of the back analyses become questionable. To overcome this dilemma, three-dimensional back analysis is recommended.
The second part is for a discussion on the accuracy of the back analyses, that generally depends on the way in which the input data is introduced in the analyses. In this paper, the “dual back analysis” method is proposed to increase this accuracy.
