大断面黄土隧道施工工法研究

以墩梁隧道为背景，采用高精度全站仪和反光膜片进行隧道施工现场监控量测。通过量测数据分析，比较了双侧壁导坑、单侧壁导坑和三台阶开挖施工工法在大断面黄土隧道中的适用性及优缺点，得出： 双侧壁导坑法操作安全系数高，适应性较强，控制围岩松弛效果明显，但造价高；单侧壁导坑法对围岩扰动小，但施工进度较慢；三台阶法施工进度快，但在地质较差地段变形难以控制；采取及时闭合成环的方法、重视及优化锁脚锚杆施工、控制仰拱与掌子面间的距离可有效地控制施工变形。

Research on Construction Methods for Large Cross-section Loess Tunnels

Site monitoring is made during the construction of Dunliang tunnel. Comparison and contrast are made, on basis of the monitoring results, among double side drift method, single side drift method and three bench method in terms of advantages, disadvantages and applicability. Conclusions drawn are as follows: Double side drift method has high safety coefficient, high applicability and obvious relax control effect, but has high cost; Single side drift method has little disturbance to the rock mass, but has slow construction advance rate; Three bench method has obvious advantages in construction advance rate, but has poor deformation control effect in adverse geological conditions; Countermeasures, such as timely ring forming, foot locking bolts and good control of the distance between the tunnel face and the invert, have good effect in deformation control.