In order to guarantee the stability of surrounding rock and support structure of superlarge span tunnel and realize quantification of support structure design, the optimal excavation contour line shape is obtained based on study of influence of initial ground stress on bearing arch of surrounding rock; a new quantitative design method, in which the surrounding rock is regarded as an arch structure, bolts, cables, shotcrete and lining are designed to satisfy the intensity, rigidity and stability of the arch structure, is presented to design the support structure system. The method has been successfully applied to superlarge span tunnel of Badaling Great Wall Station on BeijingZhangjiajie Highspeed Railway; and the applicable results show that the maximum accumulative settlement of crown top of largespan section is only 17.3 mm, and the relative subsidence of crown top is only 0.09%, which can meet safety requirements.

为解决超大跨度隧道围岩和支护结构的稳定性问题，实现支护结构设计的定量化，根据初始地应力对围岩承载拱受力的影响，得到围岩受力最优的开挖轮廓线形状，提出围岩支护结构体系构件化设计方法，即将隧道周边一定范围内的围岩圈作为一个拱形结构进行强度、刚度和稳定性计算，进而设计锚杆、锚索、喷射混凝土和衬砌等支护结构。围岩支护结构体系构件化设计方法成功应用于京张高铁八达岭长城站超大跨隧道的设计中。实践表明，在采用该方法设计的支护结构体系作用下，大跨段拱顶最大累计沉降仅为17.3 mm，拱顶相对下沉仅为0.09%，能够满足工程安全需要。