复合式衬砌隧道总安全系数设计法修正与应用研究

为评价复合式衬砌这一整体结构的安全性，对以往所建立的复合式衬砌隧道总安全系数设计法的不合理之处进行修正，并再次分析不同铁路隧道的安全性，同时与挪威Q法支护参数进行对比，最后结合案例说明该方法在断面形式比选方面的应用。结果表明： 1）所建立的总安全系数设计法可以为初期支护和复合式衬砌的支护构件选择、量化设计和整体优化设计提供一定的理论基础。2）采用总安全系数设计法对不同铁路隧道安全系数计算的结果与现场实际施工情况、既有隧道病害情况基本相符。3）挪威Q法提出的支护参数如果用于我国时速350 km的高速铁路双线隧道，Ⅲ、Ⅳ级围岩总安全系数满足要求且较为经济，但Ⅴ级围岩安全系数偏低；采用耐久性锚杆有利于充分发挥锚杆-围岩承载拱的支护作用，从而可以减少喷层和二次衬砌的强度，提高经济性。4）总安全系数设计法可以用于隧道断面形式与支护参数的精细比选。

Modification and Application of Design Method for Total Safety Factor of Composite Lining Tunnel

The unreasonableness of the design method for total safety factor of composite lining tunnel established in the past is modified; the safety of different railway tunnels is analyzed; the method is compared with the support parameters of the Norwegian Q method; and the method is applied to the comparison and selection of tunnel cross sections of a tunnel. The results show that: (1) The total safety factor design method can provide a theoretical basis for the selection, quantitative design and overall optimization design of support components for primary support and composite lining. (2) The calculation results of safety factors of different railway tunnels by using the total safety factor design method are basically consistent with the actual construction conditions and the existing tunnel diseases. (3) The support parameters proposed by Q method in Norway applied to 350 km/h high speed double track railway tunnel in Grade Ⅲ and Grade Ⅳ surrounding rock in China can meet the safe and economic requirements, and that applied to 350 km/h double track high speed railway tunnel in Grade Ⅴ surrounding rock in China is with low safety factor; the durable bolts are conducive to giving full play to the supporting role of bolt surrounding rock bearing arch, thus reducing strength of the shotcrete layer and the secondary lining so as to improve the economic efficiency. (4) The total safety factor design method can be used for the precise selection of tunnel cross section form and support parameters.