海底隧道二次衬砌承载力试验及安全性评价

Bearing Capacity Test on and Security Evaluation of the Secondary Lining in Undersea Tunnel

海底隧道长达100年的使用寿命中,由于种种原因,可能使二次衬砌承担荷载逐渐增大,最终导致其破坏。为模拟二次衬砌这一受力过程,进行了海底隧道7种二次衬砌类型的承载力模型试验。通过试验分析,在荷载增大过程中,二次衬砌裂缝发生、发展规律和位移、内力变化规律,得到二次衬砌裂缝承载力和极限承载力。将试验数据与二次衬砌内力和承担荷载的长期监测数据比较,评价二次衬砌的安全性。研究表明:二次衬砌产生裂缝的顺序依次是仰拱、墙角、边墙、拱部;7种二次衬砌类型具有较高承载力,尤其是S5d型;二次衬砌内力及承受荷载监测数据远小于试验数据,二次衬砌具有较高安全储备。

In the 100 years of the undersea tunnel service life,the load that the secondary lining bears would probably increase gradually and finally lead the lining to damage. For simulating this loading process of the secondary lining and the bearing capacity model tests were done on about seven kinds of the secondary linings in undersea tunnel. From these tests,with the load increasing,the mechanical crack＇s occurrence and development law of the secondary lining was analyzed. So was the displacement and internal force variation law of the secondary lining. The crack bearing capacity and ultimate bearing capacity of the secondary lining were obtained. The data from the tests were compared with the data from the long-term monitoring on the internal force of the secondary lining and the load that the secondary lining bore. The compared results were used to evaluate the security of the secondary lining. The research shows that the cracks in the secondary lining occurred by the time sequence is at the invert,the wall corner,the side wall and the vault. The seven kinds of secondary linings all have high bearing capacities,especially the type of S5 d. The values of data from long-term monitoring are far less than those of the model test data. So the secondary lining has very high safety margin.