为解决深埋富水岩体隧道三台阶法施工参数优化问题，以崇礼高速铁路正盘台隧道三台阶法施工参数优化为例，以上台阶开挖高度、上台阶长度、下台阶长度和单步开挖进尺为参数，采用三水平流固耦合数值模拟正交试验，进行围岩稳定性分析和参数优化。计算结果表明： 1）上台阶开挖高度对拱顶下沉、侧墙水平位移、开挖面挤出位移、塑性区范围的影响最显著。2）Ⅳ级围岩地段，上台阶开挖高度取开挖跨度的27.8%，约为4 m； 上台阶长度和下台阶长度均取开挖跨度的55.6%，约为8 m； 单步开挖进尺取开挖跨度的20.8%，约为3 m。

To conduct parameter optimization for threebench construction method of tunnels in deep waterrich rocks, the Zhengpantai tunnel of the Chongli highspeed railway is taken for an example to carry out surrounding rock stability analysis and parameter optimization using three level orthogonal tests of fluidsolid coupling numerical simulation considering the height of the heading, the length of the upper bench, the length of the lower bench, and the advancement step length as the parameters. The results show that: (1) The height of heading has an obvious influence on the crown settlement, the wall displacement, the intrusive displacement of the face, and the scope of the plastic zone. (2) In the grade Ⅳ rocks, the excavation height of the upper bench is 27.8% of the excavation span, reaching 4 m, and the upper bench and the lower bench length is 55.6% of the excavation span, reaching 8 m, and the length of advancement step is 20.8% of the excavation span, reaching 3 m.