为研究机械法联络通道多种施工参数对隧道结构及周围地层环境的影响效应，采用基于Sobol理论的全局敏感性分析方法，建立精细化表达隧道结构及施工辅助设施设计特征的有限元数值模型，结合全施工过程数值模拟试验及监测分析验证，开展施工参数全局敏感性影响分析。结果表明： 1）破洞施工使得主隧道最大变形位移相比施工前增加约34%，最大应力水平增加15.5%，接触界面膜应力增加5%~8%，内支撑体系应力水平为-12~40 MPa，施工完成后有一定程度的回弹或减少； 2）被切削环开洞口附近应力变形变化较明显，管环横截面内外边缘主应力Ⅲ分布曲线呈纺锤形等几何特征； 3）地表位移和隧道变形的计算结果与相应监测值的平均值曲线及变化趋势接近，验证了数值模型结果的合理性； 4）针对应力变形相关的不同施工响应目标指标，各施工参数如土舱压力、顶推力、刀盘转矩以及内支撑预应力等的敏感度大小排序各异，通过探讨敏感度最大的土舱压力参数对螺栓组轴力的影响规律特征，得出其影响安全可控。
The authors investigate the
influence of various construction parameters on tunnel structure integrity and
surrounding geological stability during the mechanical cross-passage excavation. A global sensitivity analysis based on the Sobol
method is employed in conjunction with a finite element numerical model that
simulates tunnel structure behavior and auxiliary construction facilities.
Numerical simulations are conducted throughout the entire construction process,
and the results are validated against field monitoring data. Key findings
include: (1) During lateral excavation through the main tunnel for cross-passage, the maximum displacement of the main tunnel increases by
approximately 34% compared to the pre-construction
state, while maximum stress levels rise by 15.5%, and interfacial stresses
increases by 5%－8%.
Stresses within the internal support system range from －12 MPa to 40 MPa. Additionally, structural strains and stresses
exhibit a degree of rebound or reduction after construction completion. (2)
Significant stress and deformation variations are observed near the cutting
ring opening, with principal stress Ⅲ distributions
forming spindle-shaped geometries along the inside and
outer surfaces of the cutting ring cross-section. (3)
The deformation displacement curves from numerical simulations are consistent
with field monitoring data, closely matching average trend curves and
demonstrating similar variation tendencies, thereby validating the accuracy of
the numerical model. (4) Sensitivity analysis indicates varying rankings of
construction parameters′ influence on stress and
deformation. Key influencing parameters
include chamber pressure, propulsion force, torque, and prestress in the
internal support frame. Among these, chamber pressure is identified as the most
sensitive parameter affecting bolt axial forces, which remained within a
controllable range.
