浅埋暗挖隧道开挖进尺的计算方法探讨

Research on calculation method of digging length in tunnel with underground excavation under shallow cover

浅埋暗挖隧道施工过程中,合理确定开挖进尺的大小至关重要,开挖进尺过小,则开挖工期延长,临时支护增加;开挖进尺过大,易引起隧道上覆土层不稳定,甚至塌方。从普氏平衡拱理论和太沙基松散介质理论出发,推导了开挖进尺的计算公式,并结合工程实例进行了分析。结果表明,所推公式具有合理性。

In the process of construction of the tunnel underground cutting with shallow overburden,it is crucial to rationally delimit the size of digging length. If the size of digging length is too small,the construction time will be prolonged and temporary protection will increase. If the size is too large,the earth on the top of the tunnel will be unstable,it will even collapse. Based on equilibrium arch theory and Terzaghi's loose medium theory,this paper proposes the calculating formula of digging length and analyzes loose medium in a construction project.