| Submarine tunnel has the characteristics of difficult geological exploration,long-term high-pressure dynamic and hydrostatic pressure on surrounding rock and supporting structure,difficult waterproof and drainage,low arching effect of surrounding rock and poor stability,which make the construction of submarine tunnel extremely difficult.Especially when several tunnels pass through the deep trough area at the same time,and the tunnels are close to each other,the tunnels will inevitably affect each other in the process of excavation.Therefore,approaching tunnel construction through weathered deep trough section is a key problem in the construction of submarine tunnel,and it is also a key technology to promote the development of submarine adjacent tunnel construction.Based on the Xiamen Haicang Tunnel and its service tunnel,the service tunnel is used as the control and protection object,and a three-dimensional calculation model of the subsea tunnel is established by using finite element numerical simulation methods.The main line tunnel blasting parameters are used as variables.The vibration speed,deformation and force of the lining structure of the service tunnel during vibration reduction measures have summarized the following results:(1)Based on the actual blasting monitoring data at the site,the formation parameters applicable to the blasting area were obtained by regression analysis using Sadovsky’s formula.(2)Three rows of vibration reduction holes can reduce the vibration rate of the service tunnel by 40%,and the blasting interval can be reduced by 30% when the interval is 125 ms.(3)When three rows of vibration reduction holes are used,the first principal stress adjacent to the second lining of the service tunnel will be reduced by 39.2%,and when the blasting interval is 150 ms,the third principal stress will be reduced by 57% and the blasting interval.Reduced by 60.2% at 150 ms.The above results obtained in this paper can be used as a reference for similar projects in this area. |
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