公路隧道结构计算的分项系数法

应用概率极限状态设计方法是当今国内外结构设计发展的必然趋势。为了推进分项系数法在公路隧道结构设计中的应用，结合隧道结构和分项系数法的特点，针对不同的隧道建设工法及结构安全等级，提出各分项系数的取值建议，并对各分项系数进行经验校准。得到如下结论： 1)当隧道结构安全等级为一级时，根据本文给出的分项系数的计算结果，结构的总体安全水平略高于传统设计方法； 2)当结构安全等级为二级时，其总体安全水平与传统设计方法相当； 3)安全等级为三级时比传统方法略低。建议推行基于结构可靠度理论的分项系数法。本文对隧道设计规范修编具有较大的参考价值。

Partial Factor Method for Structure Calculation of Highway Tunnels

It is a worldwide inevitable trend to adopt probability limit state design method in the structure design. In order to promote the application of partial factor method in the structure design of highway tunnels,the authors make proposals on the partial factors,considering the characteristics of the tunnel structure and the partial factor method,as well as considering the tunnel construction method and the structure safety grade. The authors also make calibrations on these partial factors on basis of experiences. Conclusions drawn are as follows： 1） For tunnel structures with Grade I safety level,the total safety factor obtained by partial factor method is higher than that obtained by traditional design method; 2） For tunnel structures with Grade II safety level,the total safety factor obtained by partial factor method is almost the same as that obtained by traditional design method; 3） For tunnel structures with Grade III safety level,the total safety factor obtained by partial factor method is slightly lower than that obtained by traditional design method. The authors propose that the partial factor method based on reliability theory should be adopted in the new standards, specifications and codes. The paper can provide reference for the revision of the tunnel design standards in the future.