Abstract: The construction monitoring including steel arch stress and crown settlement of Mopanshan Tunnel was implementapp:modword:implemented to know the mechanics characteristic of the shallow-buried bias loess tunnel, and the support structure of tunnel was analyzed using numerical simulation. The results showed that the tunnel arch produced migration; the stress of steel arch frame was complex; due to the thin overlying soil, the force applied on steel arch was small and the greatest stress was far smaller than yield strength of steel, so safety stock of steel arch was bigger; the big pipe-roof had an important role to constrain the deformation of surrounding rock and to prevent collapse.

摘要： 为了解黄土隧道浅埋偏压段初期支护结构的受力状况，对磨盘山隧道进口浅埋偏压段的钢架应力及拱部下沉进行施工监测，并采用数值模拟对隧道支护结构进行计算分析。结果表明：在浅埋偏压条件下，黄土隧道拱部发生了偏移；钢拱架受力较复杂，但由于上覆土薄，钢拱架总体受力较小，最大应力远小于钢拱架屈服强度，表明钢拱架在支护体系中安全储备较大；由于上覆土薄，容易发生塌方，采取长大管棚超前支护并填土反压措施的作用明显。建议在黄土隧道浅埋偏压段施工采取填土反压措施减缓地形偏压。