Structural stability analysis and deformation control of constraint-anchorage support system in soft rock mass tunnel

Abstract

The primary support of the soft rock mass tunnel is prone to lose its bearing capacity in advance due to the buckling instability. To solve it, the buckling critical load formula was derived in combination with structural stability theory. It is found that the stability can be improved by strengthening or increasing the constraint conditions for the structure. Consequently, a constraint-anchorage support system was proposed inspired by this conclusion. It provides effective constraints for the primary support by anchoring the pipes in deep rock mass with grouting high-performance material, and connecting with the primary support by I-beam connector. Reasonable support parameters were presented by analyzing the influence of support parameters on the deformation and stress of the tunnel structure. Finally, this support system was applied to the actual the tunnel construction. It was found that the stability of the primary support was improved and the tunnel deformation was effectively controlled.

Keywords

• Tunnel engineering
• Soft rock mass
• Instability failure
• Constraint-anchorage support system
• Deformation control