浅埋暗挖隧道施工引起的地表塌陷分析及其控制

 防控地表塌陷特别是海床塌陷是浅埋暗挖海底隧道施工的关键问题之一，一旦发生海床塌陷，海水可能大量涌入隧道，将造成灾难性后果。因此，明确地表塌陷的发生机制、诱发因素和相应的控制措施是浅埋暗挖隧道包括海底隧道安全施工的重要保证。以深圳地铁一隧道施工引起的两次地表塌陷事故为工程背景，根据普氏平衡拱理论，对浅埋暗挖隧道施工引起的地表塌陷进行深入的分析，明确地表塌陷的发生机制，并结合地层条件和施工情况给出了诱发地表塌陷的原因，在此基础上提出相应的控制技术，并在隧道后续施工中得到应用，取得了理想的控制效果。研究结果表明，严格按照浅埋暗挖法的基本原理和技术要点进行隧道施工，可以有效地避免地表塌陷事故的发生。研究成果对浅埋暗挖城市地铁隧道和海底隧道等类似工程施工预防地表塌陷具有一定的指导意义。

ANALYSIS OF GROUND SUBSIDENCE INDUCED BY SHALLOW-BURIED TUNNEL CONSTRUCTION AND ITS CONTROL TECHNIQUES

It is the key issue to prevent ground subsidence，especially seabed subsidence during the construction of shallow-buried subsea tunnels. So it is necessary to analyze the ground subsidence caused by the construction of shallow-buried tunnels including subsea tunnels in order to find out its forming mechanisms，inducing factors and control measures. Based on two ground subsidence accidents caused by the construction of a certain shallow-buried tunnel in Shenzhen subway，the equilibrium arch theory of М·М·Протодьяконов is used，and the forming mechanisms of ground subsidence induced by shallow-buried tunneling are presented. Predominant factors，which cause the collapse of ground，are analyzed according to stratum geological conditions and construction methods. Moreover，control techniques of avoiding ground subsidence accident are also proposed，and are applied to the tunnel construction in Shenzhen subway subsequently. Good effects were achieved in guiding the construction of the subway tunnel and ground subsidence accidents were also avoided. Research indicates that if shallow-buried tunneling can be strictly kept to the principles and technical rules of shallow-buried tunneling method，ground subsidence can be avoided effectively. The research results can provide references to preventing ground subsidence induced by construction of shallow-buried urban subway tunnels，subsea tunnels and other similar tunnel engineering.