膨胀性黄土隧道钢拱架–格栅联合支护力学特性研究

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。

The mechanical behavior of composite supports of steel-grid in loess tunnel

The problem of tunnel supporting in the expansive loess was investigated in this paper. A mechanical model for composite supports was established employing the theory of elastic shells. An improved procedure for computing the characteristic curve of ground supporting for tunnel in expansive loess was presented with the equivalent section approach and an expansive force variable. The study on the mechanical behavior of primary supports in loess tunnel was performed based on the proposed model and method. And then a suitable composite supports of steel，gird and shotcrete for the expansive loess tunnel was proposed. The model and method established were proved appropriate for the mechanical characteristic analysis of primary supports for tunnels in expansive loess，and it explained the failure of original primary support theoretically. The composite support allows the different materials to fully display its potentials to ensure the stability of tunnel and therefore have an advantage over the support methods of steel-shotcrete and grid-shotcrete.