Abstract: According to the monitored data in Yinzuiyan tunnel, the displacement back analysis of surrounding rock of highway tunnel was studied based on BP neural network. The excavation and lining of tunnel was simulated by FLAC3D to establish the relationship between the parameters combination of tunnel and the displacement calculation, then the samples used to BP neural network's training and testing was established, too. The model of displacement back analysis was obtained by training and testing these samples. Finally, the mechanical parameters of surrounding rock stability was back analyzed based on this model according to the monitored data in Yinzuiyan tunnel, in which the mechanical parameters was provided for the stability evaluation of surrounding rock of Yinzuiyan tunnel.  

Key words: displacement back analysis, FLAC , 3D, BP neural network