为了探究盾构施工引起的不同桩-隧间距下的单桩动力响应规律，依托济南地铁4号线某工区，采用离散元与有限差分耦合法（DEM-FDM），结合现场实测数据，建立隧道结构-土体-桩二维动力耦合模型。利用DEM模拟岩土材料的特性，结合FDM对混凝土结构的高效动力计算，模拟距隧道18 m范围内不同桩-隧间距下的单桩动力响应工况，并对盾构施工振动时程数据和频谱特征进行监测与分析。研究结果表明： 1）盾构隧道施工引起的邻近桩振动响应随桩-隧间距的增加呈现出幂函数或指数型衰减规律，其中，桩顶的衰减较不显著，桩底及与隧道同埋深的部位衰减较为显著； 2）基于桩-隧间距的不同，影响范围可分为强影响范围（＜3 m）、中强影响范围（3~9 m）、中弱影响范围（9~12 m）、弱影响范围（＞12 m）4部分； 3）随着桩-隧距离的增加，振动信号中的高频成分逐渐消失，而低频成分则能够传播较远距离，仍会引起桩的伴随振动； 4）盾构施工振动产生的能量90%以上集中在0~64 Hz，低频段振动对结构的影响更加显著。
The authors investigate the
dynamic response patterns of single piles at varying pile-to-tunnel distances induced by shield
tunneling. The discrete element method-finite
difference method (DEM-FDM) is employed to develop a
two-dimensional dynamic coupling model of the tunnel
structure, soil, and pile, based on field measurement data. A case study is
conducted on a section of Jinan metro line 4 in China. DEM is used to simulate
the properties of soil materials, while FDM enables efficient dynamic
calculations of concrete structures, simulating the dynamic responses of single
piles within an 18 m radius of the tunnel under different pile-to-tunnel distances. Shield tunneling
vibration time-history data and spectral
characteristics are monitored and analyzed, and the results reveal the
following: (1) The vibration response of adjacent piles caused by shield
tunneling follows a power-law or exponential decay
pattern as the pile-to-tunnel
distance increases, with less significant attenuation at the pile top and more
pronounced attenuation at the pile bottom and at the depth corresponding to the
tunnel. (2) Based on different pile-to-tunnel distances, the tunneling influence range is classified into
four categories: strong influence (<3 m), moderately strong influence (3－9 m), moderately weak influence (9－12 m),
and weak influence (>12 m). (3) As the pile-to-tunnel distance increases, the high-frequency
components of the vibration signals gradually diminish, while low-frequency components propagate further, still inducing vibrations in
the pile. (4) Over 90% of the shield tunneling vibration energy is concentrated
in the 0－64 Hz range, with low-frequency vibrations
exerting a more significant impact on structures.
