铁路隧道衬砌极限状态法设计验证研究

Research on Design Verification of Limit State Method for Railway Tunnel Lining

为了验证极限状态法在隧道衬砌设计中的可操作性,分别采用极限状态法和破损阶段法对铁路隧道衬砌进行了试设计,并对比分析了两种方法的试设计结果。研究结果表明:(1)当衬砌为素混凝土结构时,极限状态法的计算厚度均比破损阶段法计算厚度大,最大相差20 cm,需对极限状态法抗裂验算公式中的调整系数γ_d重新校核,校核后γ_d=1.55;(2)针对钢筋混凝土衬砌结构及明洞结构,极限状态法的设计结果与破损阶段法设计结果基本相同,钢筋混凝土结构的极限状态方程中相关分项系数及调整系数取值是合理的。(3)采用极限状态法(γ_d=1.55)与破损阶段法试设计工程投资相当,极限状态法较破损阶段法工程投资增加237万元,增加1%。

In order to explore the feasibility of the limit state method in tunnel lining design,in this paper,the limit state method and the damage stage method are used to test the design of railway tunnel lining,and the test results of the two methods are compared and analyzed.Conclusions are as follows：（1） For concrete lining,the calculation thickness obtained from limit state method is higher than that from damage stage method,and the maximum difference reaches 20 cm,that means it＇s necessary to get the cracking resistance coefficient（γd） of limit state method recalibrated,and the final value is 1.55;（2） For the reinforced concrete lining structure and open-cut tunnel structure,the design results base on the limit state method and damage stage method are basically in agreement which means the value of partial coefficient and adjustment coefficient in the limit state equation of reinforced concrete structure are reasonable;（3） the project investment based on the limit state method when the value of γd equals 1.55 and damage stage method are basically the same,the investment based on limit state method is 2370 thousand and 1% more than that based on damage stage method.