爆破地震波作用下既有圆形隧道衬砌动应力集中系数分析

将爆破地震波进行合理近似简化，采用波函数展开法，推导出无限岩石介质中爆破地震波作用下隧道围岩和衬砌动应力集中系数的表达式。结合具体算例，分析隧道不同位置上爆破地震波主频、隧道几何参数和隧道围岩和衬砌物理力学指标对动应力集中系数的影响。分析结果表明，爆破地震波主振频率对隧道围岩和衬砌中的动应力集中系数（DSCF）影响较大，隧道不同位置和不同方向应力的动应力集中系数随主振频率的变化趋势不同，低主振频率引起的动应力集中系数较大，不利于隧道的抗爆破振动；隧道几何参数对隧道围岩和衬砌内侧切向应力动应力集中系数影响趋势不同；隧道衬砌弹性模量对隧道结构动应力集中系数影响较大，泊松比次之；泊松比较大的隧道围岩具有一定的抗爆破振动作用，但效果有限。

Analysis of dynamic stress concentration factor for existing circular tunnel lining under blasting seismic wave

The blasting seismic wave is simplified reasonably. Based on wave function expansion method, the dynamic stress concentration factor equation of tunnel surrounding rock and lining under the blasting seismic wave is deduced in infinite rock. Combining with a typical case, the influences of the main frequency of the blasting seismic wave, geometric parameters and the physico-mechanical indices of tunnel surrounding rock and lining on dynamic stress concentration factor in the different positions of tunnel are analyzed. The analytical results show that the trend of dynamic stress concentration factor of different direction stresses with the main frequency of the blasting seismic wave are different at different positions. The dynamic stress concentration factor caused by the blasting seismic wave with low main frequency of the blasting seismic wave is larger, which is unfavorable for blasting vibration resistance. The influence trend of tunnel geometric parameters on the dynamic stress concentration factor of tangential stress of tunnel surrounding rock and lining is different. The elastic modulus of tunnel lining has a greater effect on dynamic stress concentration factor than the Poisson’s ratio. The tunnel surrounding rock with larger Poisson’s ratio have the effect of blasting vibration resistance, but the effect is limited.