浅埋暗挖法在砂壤地层中的技术应用

Technical Application of Shallow Buried Excavation Method in Sandy Loam Stratum

文中以南水北调中线干线下穿京石高速公路匝道隧洞工程为例,介绍了水工隧洞采用浅埋暗挖法穿越砂壤地层施工时的具体施工方法和施工技术。隧洞采用CD法浅埋暗挖工艺开挖,隧洞采用钢支撑与隧洞支撑结构将隧洞左右分施工区域分别错距开挖,通过超前小导管注浆加固开挖线外围岩,支设钢筋格栅,喷射混凝土,待混凝土强度达到设计强度70%时,回填灌浆填充混凝土收缩间隙,使隧洞结构与围岩共同受力。

Taking the ramp tunnel project of the middle route of the South-to-North Water Diversion Project under the Beijing-Shijiazhuang expressway as an example,this paper introduces the specific construction methods and techniques of the shallow buried excavation method in the construction of the hydraulic tunnel through the sandy loam stratum.The tunnel is excavated by CD method.The tunnel is divided into left and right construction areas by steel support and tunnel support structure.Two areas are excavated separately.The surrounding rock outside the excavation line is reinforced by advance small pipe grouting.Reinforcement grid is set up and shotcrete is sprayed.When the concrete strength reaches 70%of the design strength,backfill grouting is used to fill the concrete shrinkage gap,The tunnel structure and surrounding rock are stressed together.