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基于有效应力分析法,运用有限差分程序FLAC2D对可液化地层狮子洋盾构隧道在不同地震波激励、不同入射方向下的地震响应和地基加固减震效果进行研究和评价,为类似工程抗震设计和施工提供理论指导。结果表明:在等强度的不同地震波作用下,结构地震响应的总体规律基本相同,只是由于地震波的频率特性和持时不同,结构响应峰值到达时刻亦不同;同一地震波、不同入射方向下,结构内力的分布、发展规律差异较大,水平地震作用对结构的破坏性明显比竖向垂直地震波大;在100年2%概率水平地震作用下结构最大拉、压应力分别为1.61MPa和10.13MPa,分别发生在拱顶和右侧环偏下约45°的位置;结构满足抗震要求,但衬砌顶部拉应力达到了结构抗拉强度的85.2%,应采取加固措施;基于多种加固方案的对比研究,认为狮子洋隧道地基加固范围取5m,地基强度参数提高至原来的2倍较为经济合理。
Based on the effective stress analysis method, the finite difference program FLAC2D is used to study and evaluate the seismic response of liyangyang shield tunnel in liquefiable stratum under different seismic excitation and different incident directions and the effect of foundation reinforcement and damping. For similar seismic design and construction Provide theoretical guidance. The results show that under the same intensity of different seismic waves, the general laws of seismic response of structures are basically the same except that the peak response times of structural responses are also different due to the different frequency characteristics and duration of seismic waves. In the same seismic wave and different incident directions, The distribution and the development law are quite different. The destructive effect of the horizontal seismicity on the structure is obviously larger than that of the vertical vertical seismic wave. The maximum tensile and compressive stresses under the 2% probability level of 100 years are 1.61MPa and 10.13MPa respectively, respectively The structure meets the seismic requirements, but the tensile stress at the top of the lining reaches 85.2% of the tensile strength of the structure, and the reinforcement measures should be taken. Based on the comparative studies of various reinforcement schemes, It is more reasonable and reasonable to consider the consolidation range of the Lion’s tunnel foundation as 5m and the improvement of the foundation strength parameter to twice that of the original.