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为了研究膨胀性黄土隧道围岩与支护结构作用机制,解决膨胀力作用下的隧道支护难题,利用弹性薄壳理论建立了联合支护的力学分析模型,引入等效截面法和膨胀力参数得到了改进的围岩–支护特征曲线。基于上述模型和方法,对该黄土隧道初期支护的力学特性进行分析,提出适用于膨胀性黄土隧道的“格栅拱架+钢拱架+喷射混凝土”联合支护方式。结果表明:所建立的模型和方法对膨胀围岩条件下初期支护的力学特性分析具有较好的适用性,从理论角度解释该隧道原始初期支护发生破坏的原因;与“钢拱架+喷射混凝土”和“格栅+喷射混凝土”支护方式相比,提出的联合支护方式在膨胀性黄土隧道中更具优势,充分发挥了不同材料的承载特性,保证了隧道的稳定性。
In order to study the mechanism of surrounding rock and supporting structure of expansive loess tunnel and to solve the problem of tunnel support under the action of expansive force, the mechanical analysis model of joint support is established by means of elastic thin shell theory. The equivalent cross section method and expansive force parameters The improved surrounding rock-support characteristic curve is obtained. Based on the above models and methods, the mechanical characteristics of the initial support of the loess tunnel are analyzed, and the “grille arch + steel arch + spray concrete ” joint support method is proposed for the expansive loess tunnel. The results show that the proposed model and method have good applicability to the analysis of the mechanical characteristics of the initial support under the condition of expansive surrounding rock, and explain the reason of the initial failure of the tunnel support from a theoretical point of view. + Jetting concrete “Compared with the” grid + jetting concrete "supporting method, the proposed joint supporting method has more advantages in the expansive loess tunnel, giving full play to the bearing characteristics of different materials and ensuring the tunnel’s stability.