In-situ monitoring and analysis on the stability of surrounding rock of Qiankeng tunnel

Qiankeng tunnel of Dongshen water supply project is 322m long. The types of surrounding rock are whole weathering, IV and V class granite. The entire tunnel is under bad geological conditions. Based on the new Austrian tunneling method and considering the field geological conditions, the form of supporting and lining structure, the deformations are monitored for surrounding rock, supporting structure, and lining structure during the construction of tunnel. Various influencing factors on the deformation stability are analyzed including the stress of surrounding rock, surrounding rock structure, unloading effect, deformation mechanism, deformation time space effect and deformation response. This study plays an important role in the construction safety and provides adequate information for the post monitoring.