为解决隧道建设过程中初期支护变形侵限严重、频繁塌方等问题，依托G0615久治至马尔康高速公路查针梁子隧道进行研究，通过微台阶开挖、增大预留变形量、双层钢架支护、加强锁脚、机械化施工快速封闭成环、加强施工管理等工程措施，有效控制了围岩大变形。研究结果表明： 1）通过针对性的加强支护参数，能够控制初期支护变形，有效开挖，初期支护侵限率由最初的29%下降为0。 2）通过缩小台阶长度，采用微台阶，单工序，减小了初期支护封闭成环时间，封闭成环时间由40~50 d减小到15~20 d。3）由于空间有限，适时引进部分机械设备，采用了立架台车，可有效减少立架时间，加快施工进度，单掌子面月（最低）掘进进尺由6 m/月提高到36 m/月。
Tunnel construction often
encounters severe deformation and frequent collapse of primary support. Thus, a
case study is conducted on the Chazhenliangzi tunnel of the G0615 Jiuzhi-Maerkang expressway. A series of technologies, such as micro-bench excavation, increasing the reserved deformation, double-layer steel frame support, strengthening locking feet, mechanized
construction to quickly seal the ring, and strengthening construction
management, are adopted to effectively control the large deformation of the
surrounding rocks. The research results indicate the following: (1) By
strengthening the support parameters in a targeted manner, the primary support
deformation can be controlled, effective excavation can be achieved, and the
primary support intrusion rate can be reduced from 29% to 0. (2) By reducing
the length of the benches, adopting micro-bench, and a
single process, the primary support closure time is reduced from 40－50 days to 15－20 days. (3) Due to limited
space, some mechanical devices are introduced in a timely manner, and a gantry
trolley is used to effectively reduce the erection time and accelerate the
construction progress. The minimum monthly excavation footage of a single face
is increased from 6 to 36 m.
