海底隧道管节接头防火试验

Experiment on Fireproofing of Tube Joint of Subsea Tunnel

为了研究海底沉管隧道管节接头的防火构造与防火性能,采用自主设计建造的燃气式高温试验炉,以国际RABT标准温升曲线作为火灾边界输入,进行了多工况1∶1全尺寸构件明火试验,分析了管节接头在2种防火构造下的防火性能与温度分布。结果表明:作为一种包含钢剪力键的复合材料构件,管节接头的防火性能最终受制于耐温极限仅为100℃的Ω橡胶止水带;管节接头的防火效果取决于防火隔断的设计,采用外挂防火板与内置防火隔断的双层防护方案,即2cm厚外挂防火板+防火隔断(1cm厚防火板+1cm厚防火棉+3cm厚防火板+轻钢龙骨),可确保管节内Ω橡胶止水带的火灾历时温度低于其防火极限;当双层防护构造采用分离式铆固时,受明火火灾动力冲击影响大,外挂防火板首先开始破坏,进而导致管节接头整体防火失效。通过试验,推荐海底沉管隧道管节接头采用双层防护整体式铆固防火构造方案。

In order to study the fire protection structure and fireproofing performance of tube joint of subsea immersed tunnel,agas type high temperature test furnace originally designed and built was adopted.Taking international RABT standard temperature rising curve as fire boundary input,open fire tests under multiple working conditions were done for tunnel tube joint element by 1∶1scale.Both fireproof performances and temperature distributions of tube joint under two fire protection constructions were analyzed.The results show that as a composite joint element including steel shear,the fireproof performances of tube joint is finally subject to Ω rubber waterstop whose ultimate work temperature is 100 ℃.Fireproofing effect of tube joint finally depends on the design scheme of fire partition.A double-layer protection design in an external cladding fireproof board and an internal fire partition has been put forward,which involves 2cm external cladding fireproof board in thickness and internal fire partition composed of 1cm fireproof board,1cm fireproof fibres,3cm fireproof board and a set of light steel keel.This kind of design can make sure thatΩrubber waterstop goes through the fire below its temperaturelimit within tube joint.When a double-layer fireproof construction is riveted separately,the impact of open fire is great.External fireproof board would first be damaged and then tube joint is in general failure.Though test,a double-layer fireproof construction and integrated riveting technique have been proposed for the design of tube joint of subsea immersed tunnel.