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软弱富水地层承压水对掌子面极限支护力的影响

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软土地层盾构隧道前方存在承压含水层会对掌子面的稳定性构成重大威胁，因此，考虑承压水对掌子面极限支护力的影响至关重要。首先，采用有限元数值软件分析了不同承压水头、隔水层厚度、埋深、盾构直径、土体黏聚力以及内摩擦角条件下掌子面的失稳模式，并统计了各个条件下的极限支护力。随后，结合上述影响因素，采用多元线性回归方法，推导出计算掌子面极限支护力的简明公式。最后，结合事故案例，将本文提出公式的结果与以往传统理论解对比，验证了其有效性。分析得出以下结论:1)承压水影响软土地层隧道掌子面的失稳模式，当承压水头较小时，掌子面前方水力梯度也较小，塑性区失稳形状呈螺旋状，随着水头升高，螺旋倾角增大，失稳形状向圆柱形转变。2)统计各工况下的结果发现，隧道掌子面稳定所需的极限支护力随承压水的水头、隧道尺寸和埋深近似线性增加，与隔水层厚度、土体内聚力和内摩擦角成反比。3)通过工程案例研究分析，本文公式结果与传统理论方法的结果吻合较好，验证了本文所提公式的合理性。此外，所提出的方程克服了传统理论方法在考虑不透水层厚度变化影响方面的局限性，可以准确描绘盾构隧道掘进过程中保持隧道工作面稳定性所需的极限支护力的动态变化，从而更好地反映工程实际。
Influence of confined water on the limit support pressure of tunnel face in weakly water-rich strata
In the process of shield tunneling through soft soil layers,the presence of confined water ahead poses a significant threat to the stability of the tunnel face.Therefore,it is crucial to consider the impact of confined water on the limit support pressure of the tunnel face.This study employed the finite element method(FEM)to analyze the limit support pressure of shield tunnel face instability within a pressurized water-containing layer.Subsequently,a multiple linear regression approach was applied to derive a concise solution formula for the limit support pressure,incorporating various influencing factors.The analysis yields the following conclusions:1)The influence of confined water on the instability mode of the tunnel face in soft soil layers makes the displacement response of the strata not significant when the face is unstable;2)The limit support pressure increases approximately linearly with the pressure head,shield tunnel diameter,and tunnel burial depth.And inversely proportional to the thickness of the impermeable layer,soil cohesion and internal friction angle;3)Through an engineering case study analysis,the results align well with those obtained from traditional theoretical methods,thereby validating the rationality of the equations proposed in this paper.Furthermore,the proposed equations overcome the limitation of traditional theoretical approaches considering the influence of changes in impermeable layer thickness.It can accurately depict the dynamic variation in the required limit support pressure to maintain the stability of the tunnel face during shield tunneling,thus better reflecting engineering reality.

weakly water-rich strataconfined aquiferlimit support pressurefinite element methodmultiple linear regression

李运发、伍国军、陈卫忠、袁敬强、霍梦喆

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State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,430071,China

University of Chinese Academy of Sciences,Beijing,100049,China

软弱富水地层 承压含水层 极限支护力 有限元法 多元线性回归

Key Deployment Projects of Chinese Academy of SciencesProjectssupported by the National Natural Science Foundation of ChinaProjectssupported by the National Natural Science Foundation of China

ZDRW-ZS-2021-35217911651991392

2024

10.1007/s11771-024-5715-3

中南大学学报(英文版)
中南大学

中南大学学报(英文版)

CSTPCDEI
影响因子：0.47
ISSN：2095-2899
年,卷(期)：2024.31(8)