兰渝铁路两水隧道全长5945.35 m,设计为单洞双线隧道,洞身穿过志留系炭质千枚岩地层,属于高地应力,施工中出现大变形、初期支护侵限多次拆换,安全风险高,施工难度极大。通过分析高地应力软岩隧道特点和大变形特征,对三台阶七步开挖法的台阶长度对变形影响进行了对比分析,认为采用微台阶法更有利于控制变形,同时配合系列变形控制技术措施,有效地控制了隧道大变形,对高地应力软岩隧道施工进行了有益的探索。and eventually the large deformation of the tunnel was controlled effectively. This case can serve as a helpful reference for the construction of soft rock tunnel with high ground stress.