岩石隧道三台阶三步开挖施工方法研究

采用传统施工方法开挖隧道时会面临围岩分割断面多、开挖进度缓慢、大型机械使用程度低、工作效率低、对围岩扰动多、台阶过长、初支封闭成环较晚等问题。针对上述问题,提出了三台阶三步开挖工法,通过采用左右侧对称开挖支护施工方法、缩小台阶长度、快速初支封闭成环等措施,减少了围岩暴露时间,缩短了仰拱初支成环时间,成环时间仅为8d。该工法工序简单,减少了临时支撑体系拆除工序,减轻了对围岩的扰动,有效减小了隧道围岩变形。

Study on construction method of three benches and three steps excavation for rock tunnel

When the traditional construction method is used to excavate the tunnel, there are many problems, such as more sections of surrounding rock, slow excavation progress, low use of large machinery, low work efficiency, more disturbance to surrounding rock, too long steps and late closure of primary support. In view of the above problems, a three benches and three steps excavation method is proposed. By using the left and right side symmetrical excavation support construction method, reducing the length of steps, speeding primary support closed into a ring, it reduces the exposure time of surrounding rock and shortens the time of the inverted arch primary support into a ring, and the ring forming time is only 8 days. The construction process is simple, and it reduces the demolition process of temporary support system, reduces the disturbance to surrounding rock, and effectively reduce the deformation of tunnel surrounding rock.