大直径盾构隧道衬砌力学响应关系量化研究

Quantitative Research on Mechanical Responses of Large-Diameter Shield Tunnel Linings to Loads

为深入研究大直径盾构隧道衬砌力学响应的量化关系,以华南地区某大直径盾构隧道陆域段为研究背景,利用岩土工程有限元分析软件Midas GTS开展研究。选择匀质圆环-地基弹簧模型作为计算模型,同时结合工程概况对计算参数进行合理取值,从而得到不同埋深和水深条件下变形和内力特征变量的变化规律。结果表明,除最小轴力外其余内力最值出现位置与顶部荷载水平L_(t)和横竖荷载比Rhv的关系图表现为明显的阶梯状,且致使不同内力最值位置的阶梯突变条件存在差异;同等条件下,内力最值与L_(t)呈现正相关,最小轴力随Rhv增加而增加,而最大轴力在某一分界线两侧增减性相反,弯矩和剪力最大值基本随Rhv的增加而单调递减,说明内力最值在不同程度上同时受两个荷载变量影响。此外,回归分析结果表明,横断面变形量和典型位置内力值基本与埋深和水深二元线性相关,且均对埋深变化更为敏感;轴力、弯矩、剪力对埋深变化的敏感性依次降低,轴力与弯矩对水深变化敏感性相当,且强于剪力。

To quantitatively investigate the mechanical response of large-diameter shield tunnel linings to loads,this study focuses on the land section of a large-diameter shield tunnel in South China.Finite element analysis software,Midas GTS,was used,and a homogeneous ring-foundation spring model was selected for calculations,with parameter values reasonably adjusted based on specific project conditions.The variation patterns of deformation and internal force characteristics were analyzed under different burial and water depths.The results showed that,except for the minimum axial force,the locations of other internal force extremum values and their relationships with the top load level(L_(t))and the horizontal-vertical load ratio(R_(hv))exhibited a distinct step-like pattern,with varying conditions for step changes in different extremum positions.Under the same conditions,internal force extremum values were positively correlated with L_(t).The minimum axial force increased with R_(hv),while the maximum axial force exhibited opposite behaviors on either side of a specific threshold.The maximum bending moment and shear force nearly decreased monotonically with increasing R_(hv),indicating that internal force extremum values were influenced by both the load variables to varying extents.Furthermore,regression analysis indicated that cross-sectional deformation and internal force values at key locations were linearly correlated with burial and water depths,with greater sensitivity to burial depth changes.The sensitivity to burial depth changes was highest for axial force,then bending moment,and lowest for shear force.Axial force and bending moment were equally sensitive to changes in water depth,both showing higher sensitivity than shear force.