地震区隧道洞门极限状态设计方法研究
|
摘要
目前在进行隧道洞门结构设计时,考虑到设计和校核的方便,将极限状态方程转化为取用分项系数的实用设计表达式。但在需要考虑地震荷载的影响时,尚没有直接用于设计的有效表达式。为此,文章通过对大量隧道洞门标准图的计算校核,提出了在普通隧道洞门设计表达式基础上修正分项系数的原则,从而满足地震区洞门设计使用要求。研究结果表明:(1)通过计算确定洞门结构的稳定性目标可靠指标最小,为结构的薄弱点;(2)利用极限状态法计算并结合相关行业规范确定隧道洞门结构的目标可靠指标;(3)通过大量洞门标准图的计算确定了一般洞门结构通用的荷载作用和结构抗力的分项系数;(4)在需要考虑地震作用时,可对一般洞门结构设计表达式的土压力分项系数作1.9/1.6倍增大调整来替代水平地震力和土的内摩擦角改变的影响。
The limit state equation for the design of a tunnel portal structure is transformed into a practical design expression using a partial factor for the sake of convenience in terms of design and inspection.No effective expression is available for use in design when it’s necessary to consider the effect of a seismic load.Based on calculations and review of many standard drawings for a tunnel portal,a principle is proposed to modify the partial coefficient based on a common design expression for tunnel portals in order to meet requirements for tunnel portal design in an earthquake zone.The results show that:1)the target reliability index for the stability of a tunnel portal structure is determined to be the smallest,so it is the weak point of the structure;2)the objective reliability index of the tunnel portal structure is determined by a limit state calculation and related industry specifications;3)the partial coefficients of the load effect and structural resistance for the general tunnel portal structure are determined by many calculations from standard drawings of tunnel portal structures;and 4)when earthquake effects should be considered,the partial coefficient of earth pressure in the design expression for the general structure can be multiplied by 1.9/1.6 so that the effects of the horizontal seismic force and changes of the internal friction angle of the soil can be avoided.
The limit state equation for the design of a tunnel portal structure is transformed into a practical design expression using a partial factor for the sake of convenience in terms of design and inspection.No effective expression is available for use in design when it’s necessary to consider the effect of a seismic load.Based on calculations and review of many standard drawings for a tunnel portal,a principle is proposed to modify the partial coefficient based on a common design expression for tunnel portals in order to meet requirements for tunnel portal design in an earthquake zone.The results show that:1)the target reliability index for the stability of a tunnel portal structure is determined to be the smallest,so it is the weak point of the structure;2)the objective reliability index of the tunnel portal structure is determined by a limit state calculation and related industry specifications;3)the partial coefficients of the load effect and structural resistance for the general tunnel portal structure are determined by many calculations from standard drawings of tunnel portal structures;and 4)when earthquake effects should be considered,the partial coefficient of earth pressure in the design expression for the general structure can be multiplied by 1.9/1.6 so that the effects of the horizontal seismic force and changes of the internal friction angle of the soil can be avoided.
引文
[1]铁道部第二勘察设计院.铁路隧道设计规:TB 10003-2005[S].北京:中国铁道出版社,2005.The Second Survey and Design Institute of China Railways.Code for Design of Railway Tunnel:TB1003-2005[S].Beijing:China Railway Publishing House,2005.
[2]铁道部专业设计院等.铁路隧道结构物设计计算丛书——洞门[M].北京:中国铁道出版社,1990.The Professional Design Institute,the Ministry of Railways.Series of Design and Calculation on Railway Tunnel Structure—Portal[M].Beijing:China Railway Publishing House,1990.
[3]景诗庭,朱永全.隧道结构可靠度[M].北京:中国铁道出版社,2002.JING Shiting,ZHU Yongquan.Reliability of Tunnel Structure[M].Beijing:China Railway Publishing House,2002.
[4]谭忠盛.隧道支护结构体系可靠度的理论研究及其工程应用[D].成都:西南交通大学,1998.TAN Zhongsheng.Theory of System Reliability for Tunnel Support Structure and Its Application in Engineering[D].Chengdu:Southwest Jiaotong University,1998.
[5]严松宏,周佳媚,高波.结构可靠性设计分项系数研究[J].西南交通大学学报,2002,37(6):623-627.YAN Songhong,ZHOU Jiamei,GAO Bo.Determination of Partial Coefficients of Structural Reliability Design[J].Journal of Southwest Jiaotong University,2002,37(6):623-627.
[6]铁道第一勘察设计院.铁路工程抗震设计规范:GB 50111-2006[S].北京:中国计划出版社,2009.The First Survey&Design Institute of Railways.Code for Seismic Design of Railway Engineering:GB 50111-2006[S].Beijing:China Planning Publishing Press,2009.
[2]铁道部专业设计院等.铁路隧道结构物设计计算丛书——洞门[M].北京:中国铁道出版社,1990.The Professional Design Institute,the Ministry of Railways.Series of Design and Calculation on Railway Tunnel Structure—Portal[M].Beijing:China Railway Publishing House,1990.
[3]景诗庭,朱永全.隧道结构可靠度[M].北京:中国铁道出版社,2002.JING Shiting,ZHU Yongquan.Reliability of Tunnel Structure[M].Beijing:China Railway Publishing House,2002.
[4]谭忠盛.隧道支护结构体系可靠度的理论研究及其工程应用[D].成都:西南交通大学,1998.TAN Zhongsheng.Theory of System Reliability for Tunnel Support Structure and Its Application in Engineering[D].Chengdu:Southwest Jiaotong University,1998.
[5]严松宏,周佳媚,高波.结构可靠性设计分项系数研究[J].西南交通大学学报,2002,37(6):623-627.YAN Songhong,ZHOU Jiamei,GAO Bo.Determination of Partial Coefficients of Structural Reliability Design[J].Journal of Southwest Jiaotong University,2002,37(6):623-627.
[6]铁道第一勘察设计院.铁路工程抗震设计规范:GB 50111-2006[S].北京:中国计划出版社,2009.The First Survey&Design Institute of Railways.Code for Seismic Design of Railway Engineering:GB 50111-2006[S].Beijing:China Planning Publishing Press,2009.