软岩隧道采用传统台阶法开挖时易出现初期支护封闭不及时、步距超标等问题，为解决上述问题，依托蒙华重载铁路部分隧道，提出台阶法（带仰拱）一次开挖施工技术，阐述三台阶（带仰拱）和二台阶（带仰拱）施工工艺流程，从结构力学与变形响应、施工便捷性与设备空间布置等方面综合分析，提出台阶高度和台阶长度的合理设置原则，结合段家坪隧道与中条山隧道现场施工情况，分析台阶法（带仰拱）一次开挖工法的工序组织、技术要点与应用效果，总结台阶法（带仰拱）一次开挖工法的施工技术特点，并提出该工法的推广应用前景。

The untimely primary support closure and overlarge of advancing distance are often encountered during soft rock tunnel excavation by bench method. As a result, onetime bench excavation method (with inverted arch) is proposed for some tunnels on Menghua heavy haul railway; the construction flowcharts of threebench method (with inverted arch) and twobench method (with inverted arch) are introduced; the construction parameters such as bench height and bench length are put forward by comprehensively analyzing the structural mechanism, deformation response, construction convenience and arrangement of equipments; the construction organization, technical key points and applicable effect of the onetime excavation method of bench and inverted arch in Duanjiaping Tunnel and Zhongtiaoshan Tunnel are presented. Finally, the construction characteristics of the abovementioned technology are summarized, and the technology is prospectively popularized.