Tunnel and Underground SpaceISSN:1225-1275(Print) 2287-1748(Online)한국암반공학회

Recently, tunnel collapse accidents have been occurring, raising concerns about tunnel safety. Because tunnels involve ground uncertainty, if they are under-reinforced in poor ground conditions, tunnel collapse accompanied by abnormal displacement may occur. General measurement management standards have been established to verify tunnel stability during construction. However, due to the lack of evaluation standard for signs of tunnel collapse, it is currently difficult to implement collapse response measures, such as additional reinforcement and emergency evacuation. This study developed a tunnel collapse evaluation standard based on abnormal displacement occurring prior to tunnel collapse. Numerical analysis was performed considering parameters such as tunnel cross-section and ground conditions. tunnel displacement and support system were evaluated when the rock strength was downgraded due to ground uncertainty. In some review conditions, it was found that abnormal displacement occurred as the stress of the support system exceeded the allowable standard due to under-reinforcement caused by ground deterioration. Based on abnormal displacements occurring in the tunnel, step-by-step tunnel collapse evaluation standard according to tunnel support patterns were developed. Through the proposed tunnel collapse evaluation standard, it will be possible to identify signs of tunnel collapse in advance and ensure tunnel stability through collapse response measures.