Damages to Metro Tunnels due to Adjacent Excavations

Abstract

Metro tunnels are vulnerable to ground movements, therefore precautionary measures must be taken to prevent potential damages to existing tunnels if excavations are to be carried out in close proximity to tunnels. Presented herein are the regulations adopted to protect the Taipei Metro and three case histories on damages occurring to metro tunnels to illustrate how tunnels respond to activities associated with excavations. It has been found that localized ground treatment would not serve the purpose of reducing wall movements and neither would a single buried cross panel in excavations with considerable lengths.