Study on Mechanical Properties of Support Structure of Deep Buried Tunnel Soft and Weak Surrounding Rock in High Situ Stress Area

Mechanical properties of bolt, shotcrete, steel support structure of initial support and lining concrete were analyzed through elasto-plastic 3D finite-element numerical simulation of bench tunneling in high geo-stress area. Results of analysis indicate that (1) strongly effected by steel support structure, displacement, maximum principal stress of shotcrete are larger at crown, displacement, maximum principal stress and shearing stress are larger at spandrel; (2) stress concentration strongly influenced on bolt axial stress at a range of 1.0 m surrounding rock; (3) axial stress and vertical shearing force of steel support structure increase gradually with distance augmentation to the tunnel face; (4) different principal stresses and shearing stresses exist at various layers and positions of lining. The conclusion provides a reference for deep-buried tunnel design of support structure and stability evaluation in high geo-stress area.