厦门海底隧道堵水限排安全监测及分析

The security monitoring and controlled drainage of Xiamen Subsea Tunnel

海底隧道应采取堵水限排的地下水处理方式,为了研究堵水限排海底隧道围岩压力、初期支护水压力和钢拱架内力在施工阶段的变化规律,结合厦门海底隧道工程,对施工现场的围岩压力、初期支护后水压力和钢拱架内力进行实时监测。研究表明,初期支护在施工阶段有较高的安全系数,止水超前注浆和初期支护背后注浆对海底隧道非常有必要。在堵水限排情况下,通过加强注浆等工程措施,初期支护水压力可降至静水压力的1/3。通过对施工现场排水量的监测与分析,提出了排水量控制标准,厦门海底隧道软弱围岩地段的排水量应按照0.25 m3/(m.d)控制。研究成果在厦门海底隧道中得到了验证和应用。

Controlled drainage should be applied to deal with underground water in subsea tunnel.In order to study the change laws of subsea tunnel wall rock pressure,water pressure on primary support and internal force of steel arching in the process of construction,combining with the Xiamen Subsea Tunnel,the real time monitor of the wall rock pressure,water pressure on primary support and internal force of steel arching were carried out on site in the process of construction.The results show that the primary support has a high security coefficient in construction period.Grouting in advance and grouting back the primary support is necessary for subsea tunnel.In the circumstance of controlled drainage,by strengthening some measures such as grouting,the water pressure on primary support can be reduced to 1/3 of the full hydrostatic pore pressure.By monitoring and analyzing the water inflow on site,the water inflow controlling criteria are put forward.The water inflow in soft rock section in Xiamen Subsea Tunnel should be less than 0.25 m3/（m·d）.The result of the paper were verified and applied in Xiamen Subsea Tunnel.