锚碇隧道开挖过程中的围岩变形特征监测分析

以雅康高速公路大渡河特大悬索桥雅安岸锚碇隧道项目为依托，通过现场监测左右洞拱顶沉降和边墙围岩变形量，分析锚碇隧道在开挖过程中的围岩变形特征及其对围岩的稳定性影响。结果表明:先行洞（左洞）受到后行洞开挖的影响，其拱顶最终沉降量由6.00 mm增加到11.50 mm，右洞的拱顶最终沉降量为8.00 mm；因左右洞中夹岩的存在，后行洞左边墙变形量大于右边墙，并使先行洞右边墙的水平变形由2.41 mm增加到3.83 mm；净距变小，埋深、断面尺寸变大使隧道的拱顶沉降增加，但对边墙围岩变形不产生明显影响。

Monitoring Analysis on the Deformation Characteristics of Surrounding Rock during Excavation of Anchorage Tunnel

The deformation characteristics and stability of the surrounding rock during the excavation of anchorage tunnel is analyzed through the field monitoring of vault settlement of left and right tunnel holes and the deformation of side wall surrounding rock based on the anchorage tunnel project on Ya’an of the super large suspension bridge across the Dadu River of Yakang Expressway. The results show that the final vault settlement of the first hole (left hole) increases to 11.50 mm from 6.00 mm influenced by the excavation of the following hole. The final vault settlement of the right hole is 8.00 mm. Due to the existence of middle rock, the deformation of the left wall of the following hole will be larger than that of the right wall and the horizontal deformation of the right wall of the first hole increases to 3.83 mm from 2.41 mm. The smaller clear distance and larger buried depth and section size will increase the vault settlement of the tunnel, however, it has no significant effect on the deformation of the surrounding rock of the side wall.