为揭示河床冲淤作用对水下盾构隧道长期服役性能的影响，基于某长江隧道的运营监测工作，通过实测数据整理以及数值模拟的方式，对历年河床高程变化、水位变化以及隧道结构响应之间的横纵向关系进行研究。主要结论如下： 1）覆土厚度的变化是影响河床冲淤过程中隧道结构响应的关键因素，其极大地影响了隧道横断面的整体沉降趋势。2）管片接缝变形与覆土厚度变化呈正相关，与水位波动呈负相关，且纵缝错台对河床沿隧道纵向的冲淤差异更为敏感。3）基于数值模拟计算，在江中右线某断面，接缝变形随水位变化的回归系数为-0.000 4～-0.004 mm/m，随覆土厚度变化的回归系数为0.003～0.03 mm/m，表明河床冲淤对隧道接缝的扰动不足以直接影响其防水性能。4）覆土厚度变化能显著改变隧道外围的土压分布，导致接缝变形随河床高程变化的回归系数明显大于随水位变化的回归系数。
To investigate the impact of riverbed scouring and
silting on the long-term service performance of
underwater shield tunnels, the authors analyze the transverse and longitudinal
relationships among historical riverbed elevation changes, water level
variations, and tunnel structural responses. The analysis is based on measured
data collation and numerical simulations using operational monitoring data from
a Yangtze river-crossing tunnel. The main findings are
as follows: (1) Overburden thickness is the critical factor influencing structural
responses during riverbed scouring and silting, significantly affecting
settlement trends of tunnel cross-sections. (2) Segment
joint deformations exhibit distinct positive and negative correlations with
overburden thickness and water level, respectively. Longitudinal joint
dislocations are particularly sensitive to uneven scouring and silting along
the tunnel axis. (3) Numerical simulations at a specific cross-section on the river′s right line show that
the regression coefficients of joint deformation with water level and
overburden thickness range from －0.000 4 to －0.004 mm/m and 0.003 to 0.03 mm/m, respectively, indicating that
scouring and silting exert insufficient disturbance on tunnel joints to
directly compromise waterproofing performance. (4) Changes in overburden
thickness significantly alter the soil pressure distribution around the tunnel,
with regression coefficients of joint deformation with riverbed elevation
notably exceeding those associated with water level variation.
