为解决隧道临时支护结构施作耗时长、拆除后难以利用的难题，提出一种可重复使用的预制临时仰拱设计与施工方案，并在黄土隧道三台阶七步法中进行应用试验。通过对比现场光纤光栅传感器测试数据和数值模拟结果，对预制临时仰拱实施效果进行研究。研究结果表明： 1）预制临时仰拱制作简单、拼装快速并可重复应用，可在大断面隧道三台阶临时仰拱七步施工方法中快速形成临时仰拱，使中台阶开挖后初期支护体系临时封闭成环； 2）与传统三台阶七步开挖施工方案相比，采用“三台阶七步开挖+预制临时仰拱”方法可以有效改善大断面黄土隧道施工中初期支护结构受力与变形，其中初期支护结构最大主应变降低约72%，拱顶沉降降低约78%； 3）设置预制临时仰拱使中台阶封闭成环，可以很好的改善初期支护结构与围岩的相互作用性能，有效减小隧道开挖后围岩塑性变形范围，保证隧道施工安全。

In tunnel construction, it often takes long time to build temporary support structure, and the teporary structure cannot be reused easily after demolition. A design and construction scheme of reuseable precast temporary invert arch is put forward, and application tests are carried out in loess tunnel with threebench sevenstep method. By comparing the field data of fiber Bragg grating sensors and numerical simulation results, the implementation effect of precast temporary inverted arch is studied. The results show that: (1) Precast temporary inverted arch is simple, and reuseable and can be assembled fast,  which helps to quickly form temporary inverted arch and close primary support structure after middle bench excavation in largesection tunnel construction with threebench seven steps method. (2) Compared with traditional threebench sevenstep excavation construction scheme, the "threebench sevenstep excavation + precast temporary inverted arch" method proposed can effectively decrease the stress and deformation of primary support structure, in which the maximum principal strain of the primary support is reduced by 72%, and the vault settlement is reduced by 78%. (3) With precast temporary inverted arch, middle bench can be sealed quickly, which improve the interaction between primary structure and surrounding rock, effectively reduce the plastic deformation range of the surrounding rock after tunnel excavation, and ensure the safety of tunnel construction.