软土地层盾构姿态偏移引起的附加土压力影响因素研究

Study on the Influence Factors of Additional Earth Pressure Caused by Shield Attitude Deviation in Soft Soil Strata

  • 摘要: 盾构隧道施工过程中盾构姿态常常会出现偏离设计轴线的现象,导致盾构隧道荷载变化。鉴于此,通过参数化分析,得到不同地层条件、隧道埋深、姿态偏移量及隧道洞径等因素下盾构姿态偏移引起的隧道附加土压力的变化规律,探明各影响因素对隧道附加土压力变化的影响程度。结果表明:任意角度下盾体偏移会导致偏移方向一侧的隧道土压力增大,对侧土压力减小;砂土地层中盾构姿态偏移所导致的隧道附加土压力变化相较于黏土地层更大,盾体偏移角度为-90°、0°及90°时,砂土地层中姿态偏移对隧道附加土压力产生的影响程度分别是黏土地层中的199.47%、636.08%、162.04%;随参数值的增大,隧道埋深与洞径对隧道附加土压力变化的影响程度逐渐降低,盾构姿态偏移量对隧道附加土压力变化的影响程度逐渐增大;隧道附加土压力对隧道埋深与洞径变化的敏感性逐渐降低,对姿态偏移量变化的敏感性基本保持不变。

     

    Abstract: During shield tunnel construction, the shield attitude often deviates from the designed axis, leading to changes in tunnel loads. In view of this, a parametric analysis is conducted to study the variation law of additional earth pressure in tunnels under different geological conditions, tunnel burial depths, attitude deviations, and tunnel diameters. And it investigates the influence of various factors on the variation of additional earth pressure. The results indicate that any angle of shield deviation will cause an increase in earth pressure on the side of the deviation and a decrease in the earth pressure on the opposite side. The variation of additional earth pressure caused by shield attitude deviation is more significant in sandy soil layers than in clay soil layers. When the shield body deviation angle is -90°, 0°, and 90°, the impact on additional earth pressure in sandy soil is 199.47%, 636.08%, and 162.04%,respectively, compared to clay soil layers. As the parameter values increase, the influence of tunnel burial depth and diameter on additional earth pressure decreases, while the influence of shield attitude deviation on additional earth pressure increases. The sensitivity of additional earth pressure to changes in tunnel burial depth and diameter gradually decreases, while the sensitivity to attitude deviation remains essentially unchanged.

     

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