本项目以港珠澳大桥沉管隧道为研究对象，综合考虑回淤厚度和海水的荷载，拟在陆基上进行1:5原沉管隧道节段断面的缩尺模型的静力加载、结构抗火试验和理论研究。试验包括：使用荷载下单孔隧道、双孔隧道结构抗火试验，测试火灾时的结构变形、温度分布和相应的声发射特性；沉管隧道节段防水接头火灾试验，测试在不同防火措施时设定火灾荷载对接头处两种止水带温度分布、缝隙等的影响。基于试验结果，分析沉管隧道结构在火灾时的温度场、变形规律、声发射特性、混凝土爆裂范围和深度、裂缝分布和破坏形式，建立有限元分析模型并加以验证，然后建立用于计算沉管隧道结构在火灾下的承载力和变形的理论模型；根据沉管隧道接头火灾试验，对不同防火措施时的节段接头温度分布进行分析，比较各种防火措施对接头耐火性能的影响，提出沉管隧道节段接头防火材料的耐火设计计算方法及相应的布置方案，最后将上述成果用于指导沉管隧道结构抗火的性能化设计。

This proposal focuses on the immersed tunnel of the Hong Kong-Zhuhai-Macao Bridge. The static loading test, fire resistance tests and theoretical investigation will be carried out on the segment model of the Hong Kong-Zhuhai-Macao Bridge with 1/5 scale. During tests, the model will be applied loading from the backfill and sea water. The tests include three tests, the first and the second are the fire resistance tests with applied loading on single bore immersed tunnel model and double bores immersed tunnel model. During tests, the structural deformation, distribution of temperature and the characteristics of acoustic emission will be recorded. The third test is the fire resistance test of the immersed tunnel segment joints with different fireproof materials and the assumed fire load, and the distribution of temperature in the water-stop belts and the variances of the joints will be recorded. Based on the experimental results, the temperature field, variances of the deformation, the characteristics of acoustic emission will be analyzed, and the finite element analytical modelling will be built and verified, meanwhile the formulas to calculate the load-bearing capacity and the deformation in fire will be developed. Considering the distribution of temperature on the water-stop belts and the variances of joints in fire, the fire resistance computing method and the fire safety design method for immersed tunnel segment joints will be developed, and the different fire materials arrangement scheme will be given as well. All the above experimental and theoretical results may provide a technical basis for the performance-based design of the immersed tunnel.