深埋隧道地层工程尺度下同震变形场研究

Co-seismic deformation field of deep buried tunnel strata at the structural scale

断层错动造成的地震同震变形场对穿越其中的隧道等长线形工程的安全有显著影响。工程尺度下的地层变形分布是此类工程的重要设计依据。基于位错模型理论,结合成层地层模型参数与多源数据联合反演得到的有限断层模型参数,计算地层同震变形场在地表与隧道埋深范围内的分布。根据计算结果,对比了不同参数影响下同震变形场在位移值与分布模式上的差异,并着重分析地层变形指标中的变形方向对结构受力的潜在影响。结果表明:从地表到地层内部,随深度增加地震同震变形场变化显著,地层变形分布模式由弯曲变形为主转变为剪切变形为主。在相同断层错动变形量的情况下,地层的变形方向对非圆形断面隧道衬砌的受力有重要影响。因此,建议将结构所处位置相对有断层上缘的相对埋深作为一个重要参数在今后地下工程抗震设防计算中予以考虑,并应验算结构处于最不利变形角度时的受力。

The coseismic deformation field caused by fault dislocation has a significant impact on the safety of long linear projects,such as tunnels,crossing them.The distribution of the stratigraphic deformation at the engineering scale is an important design basis for such projects.Based on the dislocation model theory,the distribution of the stratigraphic coseismic deformation field in the range of the surface and the tunnel depth is obtained by combining the parameters of the stratigraphic model and the parameters of the finite fault model obtained from the joint inversion of multi-source data.Based on the calculation results,the differences in the displacement values and the distribution patterns of the isoseismic deformation field under the influence of different parameters are compared and the potential influence of the deformation direction in the stratigraphic deformation index on the structural forces is emphasized.The results show that the seismic isoseismic deformation field changes significantly with increasing depth from the surface to the interior of the strata and that the distribution pattern of the stratigraphic deformation changes from bending deformation-dominated to shear deformation-dominated.For the same amount of fault deformation,the deformation direction of a stratum has an important influence on the force of the tunnel lining in non-circular sections.Therefore,it is recommended that the relative burial depth of the structure at the location relative to the upper edge of the fault be treated as an important parameter in future seismic calculations for underground engineering;furthermore,the force should be calculated when the structure is at its most unfavorable deformation angle.