京张高速铁路八达岭长城站为地下暗挖车站，过渡段设计为单跨形式，最大开挖跨度32.7 m，最大开挖面积497 m2。为了解决超大断面隧道开挖过程中围岩变形大、容易失稳，多导坑法开挖无法采用大型机械施工、进度慢，隧道内预应力锚索施工难度大等难题，文章采用顶洞超前、分层下挖、核心预留、重点锁定的开挖工法（简称“DFHZ工法”），并对该工法的优点和施工流程进行了介绍，该工法既能保证隧道开挖过程中的安全、减少围岩的沉降和变形，又方便机械化施工。采用预应力锚杆和预应力锚索结合使用，以发挥围岩的自承载能力，保证围岩稳定，预应力锚索施工中采用增设锚固结、硫铝酸盐水泥配置浆液、先自由段后锚固段的注浆顺序、高压注浆等措施，可以大大加快锚索施工进度，保证锚索质量。通过对张家口端进行监控量测，发现拱顶下沉和水平收敛值都很小，说明采用的支护措施可行，并对北京段过渡段进行了优化设计。

The Badaling Great Wall Station on BeijingZhangjiakou Highspeed Railway is an underground mined station, of which the transition section is designed as a single span with a maximum excavation span of 32.7 m and a maximum excavation area of 497 m2. The surrounding rock of superlarge crosssection tunnel is always characterized by large deformation and instability, the largescale mechanical construction cannot be applied to multiguide pilot excavation, the construction speed is low, and the prestressed anchorage cable in tunnel is difficult to be carried out. Hence, the so called DFHZ method, advanced excavation of tunnel top, layered downward excavation, core soil reserved and keys locking, is adopted, and the advantages of construction flowchart of the method are introduced. By adopting the abovementioned method, the tunnel safety can be guaranteed, the deformation and settlement of the surrounding rock can be reduced, and the mechanical construction is available. The stability of the surrounding rock can be guaranteed by using prestressed anchor rod and prestressed anchorage cable. During the construction of prestressed anchorage cable, the technologies, i.e. adding anchoring joints, setting up slurry with sulphoaluminate cement, free section grouting and then anchoring section, and highpressure grouting, etc.〖KG-*3〗, are adopted to shorten the construction schedule of anchorage cable and guarantee its safety. The monitoring results of crown top settlement and horizontal convergence at Zhangjiakou End are small, which indicates the rationality of the abovementioned method.