填方隧道地震响应影响因素分析

Analysis of Influence Factors on the Seismic Response of a Tunnel in Fills

以某隧道工程为例,建立了隧道地震动力分析数值模型,对高烈度地震区对填方地基修建的隧道结构进行动力响应特征研究,探讨隧道不同衬砌厚度、混凝土强度及覆土厚度等参数对隧道衬砌结构受力状态的影响。研究结果表明:在地震荷载作用下,衬砌厚度和覆土厚度对隧道各部位弯矩荷载值及剪力荷载值影响较大,特别是在衬砌底板与中墙连接部位影响显著;衬砌混凝土等级超过C30后对隧道衬砌结构的受力状态影响很小;对于隧道上部的回填覆土,应尽量避免单侧覆土,必要时增加水平支撑的方式以改善隧道受力状态。

The seismic response of a tunnel in fills is numerically simulated. The effect of the seismic loadings in the high earth- quake intensity zones on the stress in the tunnel lining structure in fills are modeled under different lining thicknesses, concrete strength values and fill thicknesses. The results indicate that, under the seismic loading, lining and fill thicknesses are the two major factors that are affecting the bending moment and shear force in the tunnel, especially, at the joint of the bottom slab and the mid wall. When the strength of the lining concrete is greater than 30MPa, the influence of the concrete strength on the stress in the tunnel is minimal. Unbalanced fill above the tunnel should be avoided and the horizontal internal support should be added to improve the stress state in the tunnel.