Abstract:

In order to obtain the deformation rule of the construction at the side of opening in an expansive rock tunnel, the noncontact monitoring technology, such as the system comprising a total station, was used to monitor the deformation of  2nd  Nada Tunnel on the  Yungui Railroad (Guangxi). Though monitoring and analyzing of the deformation, it was  obtained that  the deformation of convergence and ground surface became  stabilized  with the increase of time of excavation and after tunnel invert. The deformation was decreased  with the time of construction. Because of  continuous rainfall, the strength of swelling rock was reduced and the surface produced a  big crack, which caused the surface submersion to increase and a local region presented a landslide. According to the results of monitoring and analysis, the control measurements of casualties were established in the view of features of swelling rock. The measurements, such as anchor inject and micro-anti-slide pile, were able to guarantee this tunnel′s constructs safe construction.

Key words:  non-contact monitoring, tunnelling engineering, country rock deformation, total station instrument