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顺层岩体是隧道工程中常见的地质情况,震害突出,但尚无有效的地震响应分析方法,因而难以深入研究其响应机制和规律。为此,建立一种地震波动输入方法及相应公式,该方法以有限元法与时域波动分析法相结合,采用黏弹性人工边界,基于顺层岩体的横观各向同性本构关系,考虑岩体中地震波的偏振特性和相速度变化特点,适用于地震波斜入射方向与隧道纵断面平行的情况。同时,为验证所提出方法的实用性和可行性,应用其分析某顺层岩体中高速铁路隧道结构的地震响应规律。结果显示:当岩层水平或竖直时,则qP波引起的衬砌内力包络图对称;当岩层倾斜时,则qP波引起的衬砌内力包络图不对称,不对称性的幅度与岩层倾角相关;岩层倾角不同,则弯矩值相差较大;弯矩包络图无论对称与否,环向弯矩极值均位于拱脚处,而纵向弯矩极值却位于拱顶和仰拱处。此外,作为对比分析,又将岩层简化为各向同性介质,采用该方法进行计算,结果发现:P波引起的衬砌内力包络图对称,且内力包络图与将岩层简化为横观各向同性介质时相接近。这进一步验证了提出方法的合理性和可靠性。
The bedding rock mass is a common geological condition in tunnel engineering. The seismic damage is prominent, but there is no effective seismic response analysis method, so it is difficult to study its response mechanism and law in depth. For this reason, a method and corresponding formula of seismic wave input are established. This method combines the finite element method with the time-domain wave analysis method and adopts the visco-elastic artificial boundary. Based on the transversely isotropic constitutive relation of the rock mass, The characteristics of the seismic wave polarization and the characteristics of the phase velocity in the rock mass are suitable for the case that the oblique incident direction of the seismic wave is parallel to the longitudinal section of the tunnel. At the same time, in order to verify the practicability and feasibility of the proposed method, the seismic response law of high-speed railway tunnel structure in a rock mass is analyzed. The results show that when the rock formation is horizontal or vertical, the envelope of lining internal force caused by qP wave is symmetrical. When the rock slope is inclined, the envelope of lining internal force caused by qP wave is asymmetric and the amplitude of asymmetry is related to the dip of rock strata ; The bending moment values are quite different when the dip of rock strata is different. Whether the bending moment envelope is symmetrical or not, the extreme value of the toroidal bending moment is located at the arch foot, while the extreme value of the longitudinal bending moment is located at the vault and the inversion arch. In addition, as a comparative analysis, the rock is simplified as an isotropic medium, and the method is used to calculate. The results show that the envelope of internal force caused by P wave is symmetrical, Close to the same sex medium. This further verifies the rationality and reliability of the proposed method.