Abstract:

Collapses occur frequently when soft ground is tunneled through. Bondingtype glass fiber bolts are installed into the advance core soil of tunnels and grouting is executed, which can effectively improve the cohesion C, internal friction angle   and elastic modulus E of the advance core soil, in turn improves the strength and stiffness of the advance core soil, restrict the ground surface settlement and enhance the tunnel face stability. The strengthening mechanisms of tunnel face reinforced by bondingtype glass fiber bolts are studied to obtain the improving magnitude of cohesion C, internal friction angle  and elastic modulus E of the advance core soil so as to avoid tunnel collapses. The technology is trialed in Liuyanghe tunnel, which demonstrates that bondingtype glass fiber bolts can effectively improve the strength of the advance core soil and can guarantee the stability of the tunnel face and the surrounding rock mass during tunnel construction.

Key words: iuyanghe tunnel, bondingtype bolt, preconsolidation, face, advance core soil, rock mass stability