摘要
目前,我国结构设计规范中广泛采用以荷载和抗力分项系数代表概率可靠性的概率极限状态设计方法。然而,在Eurocode 7等岩土工程结构的设计规范及相关研究中,对荷载与抗力分项系数方法,即以一组固定分项系数来保证不同工况下工程结构可靠性提出质疑。基于多年来我国铁路隧道衬砌结构概率极限状态设计的研究成果与应用情况,进一步细化不同围岩分级、埋深和衬砌类型的分项系数标定,共标定28种工况下衬砌结构设计的分项系数;分别采用本文、《铁路隧道极限状态法设计暂行规范》和《铁路隧道设计规范》的衬砌结构可靠性与安全性评价指标,对京张高铁八达岭隧道8种工况下设计方案的安全性与可靠性进行对比分析,不同工况下的隧道衬砌结构设计可靠指标与安全系数差异较大,说明荷载与抗力分项系数方法在铁路隧道衬砌可靠性设计中的稳健性较差。建议在隧道设计规范层面应逐步开展基于概率可靠性地勘和计算两阶段的研究,并提出铁路隧道设计方法转轨的部分建议。
At present, the probabilistic limit state design method with probabilistic reliability represented by load and resistance partial factors is widely adopted in the structural design codes in China. However, the load and resistance partial factors method, which uses a set of fixed partial factors to ensure the reliability of engineering structures under different working conditions, is questioned in the design codes of geotechnical engineering structures such as Eurocode 7 and related researche. Based on the research results and applications of probabilistic limit state design of railroad tunnel lining structure in China over the years, this paper further refines the calibration of subfactors for different rock classifications, burial depths and lining types, and calibrates the partial factors of lining structure design under 28 working conditions. The reliability indexes and safety factors of the tunnel lining structure from this paper, Interim Code for Limit State Design of Railway Tunnel and Code for Design of Railway Tunnel are used to compare and analyze the safety and reliability of the eight working conditions of the Beijing-Zhangjiakou High-speed Railway the Badaling tunnel design scheme. The results show that the reliability indexes and safety factors of the tunnel lining structure design vary greatly under different working conditions, indicating that the LRFD method is less robust in the railway tunnel lining design. Therefore, studies on the probabilistic reliability of tunnel engineering structures at the two stages of ground investigation and calculation should be carried out gradually with respect to tunnel design specification. Some suggestions for design methods are also put forward.
作者
陈文博
张顶立
孙振宇
陈旭
孟令赞
CHEN Wenbo;ZHANG Dingli;SUN Zhenyu;CHEN Xu;MENG Lingzan(Key Laboratory for Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China)
出处
《铁道标准设计》
北大核心
2023年第1期17-24,共8页
Railway Standard Design
基金
国家自然科学基金重点项目(51738002)。