地铁隧道下穿不良地质反台阶开挖技术研究

Study on Reverse Step Excavation Technology of Subway Tunnel Passing Beneath Unfavorable Geological Conditions

结合青岛地铁暗挖隧道下穿复杂环境特殊不良地质段的施工技术探索及实际操作,系统阐述针对特殊地质情况尤其上软下硬围岩地层内的“反台阶”开挖控制爆破施工关键技术。首先对上台阶软弱围岩采取预加固措施,优化隧道开挖工序为下台阶先于上台阶开挖,从而达到安全施工的目的。现场采用反台阶控制爆破法进行开挖施工,下台阶先行控制爆破,上台阶逐层剥离控制爆破。该施工技术在青岛地铁1号线开胜区间特殊不良地质段得到成功应用并申请了国家发明专利。

In combination with the construction technology exploration and practical operation of Qingdao subway tunnel under complex environment and special unfavorable geological section,this paper expounds the key construction technology of“reverse step”excavation controlled blasting under special geological condition,especially in the stratum of upper soft and lower hard surrounding rock.In this technique,the tunnel excavation procedure is optimized to excavate the lower step before the upper step after adopting the pre-strengthening measures for the soft surrounding rock of the upper step,so as to achieve the purpose of safe construction.The excavation construction is carried out by the method of reverse step controlled blasting.The lower step is controlled blasting first,and the upper step is peeled off controlled blasting layer by layer.This construction technology has been successfully applied in the special bad geological section of Kaisheng regional tunnel of Qingdao Metro Line 1 and applied for the national invention patent.