The dynamic stress concentration series solution of cylindrical composite-lined tunnel in half space subj ected to incident plane P waves was given based on wave function expansion method.The influence of the angle and frequency of incident P wave on the dynamic stress concentration factor of different lining stiffness combination cavities was studied.The results showed that,the angle and frequency of the incident plane P waves had a significant influence on the dynamic stress concentration factor of the lined cavity.The increase of the angle and frequency resulted in more complex distribution of dynamic stress concentration factor.Under low frequency incident waves,the dynamic stress concentration factor of the rigid second lining of composite-lining cavities decreased with lower stiffness of the first lining,such as the flexible lining and buffer layer. The dynamic stress concentration of the rigid second lining decreased with the reduction of the stiffness of the first lining.Compared with high frequency incident waves,the flexible lining and damping layer had an effi-cient damping effect on the dynamic stress of the rigid secondary lining under low frequency incident waves.Fi-nally,the effects of the thickness of the buffer layers and the elastic modulus on the dynamic stress concentra-tion factor of the lining were studied combined with an actual pipeline tunnel proj ect in a seismic zone that suf-fers earthquakes of intensity MSK Ⅸ.The elastic modulus of the buffer layers is recommended to be less than 1/20 of the associated value of the surrounding rock,while the optimal thickness of the damping layers is sug-gested to be 1/25 of the diameter of the cavity clearance.%本文利用波函数展开法,给出平面P波入射下浅埋圆形双层衬砌隧道动应力集中系数级数解,并分析P波入射角和入射频率对不同衬砌刚度组合隧道动应力集中系数的影响.研究表明:P波入射角度和入射频率对衬砌洞室动应力集中系数有明显影响,随着P波入射角和入射频率增大,衬砌的动应力集中系数分布变复杂;在低频入射情况下,当组合式衬砌洞室中衬砌1为刚度较低的柔性衬砌和减震层时,刚性衬砌2的动应力集中系数明显降低,衬砌1刚度越低,衬砌2动应力集中系数越小;与高频入射波相比,柔性衬砌和减震层对低频入射波下衬砌2的动应力有更好的减震效果.本文结合某穿越Ⅸ度地震区浅埋管道隧道工程,研究减震层厚度和弹性模量对"围岩-减震层-衬砌"洞室动应力集中系数的影响,建议减震层弹性模量小于围岩弹性模量的1/20,减震层最优厚度宜取洞室内净空直径的1/25.
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