软岩小净距大变形隧道施工控制措施的优化

Optimization of construction control measures for small clear distance and large deformation tunnels in soft rock

成兰铁路杨家坪隧道处于龙门山主中央断裂带与龙门山后山断裂带之间,区内发育有与隧道基本平行的断层、背斜及向斜,构造条件复杂;围岩陡倾直立,岩质软弱,呈片状结构。隧道间最小净岩柱为1.66m,施工难度极大、安全风险高。文章结合现场测试数据分析了杨家坪隧道小净距段变形机理,总结了围岩加固及置换、优化支护结构形式、工序错位距离、非爆破开挖方式等应对小净距大变形隧道的优化措施,有效强化了软岩小净距大变形隧道的变形控制能力。

Yangjiaping tunnel of Chengdu-Lanzhou railway is located between the main central fault zone and the rear fault zone of Longmen Mountain.The surrounding rock is steep and vertical,and the rock is weak,showing sheet structure.The minimum net rock column between tunnels is 1.66m,which is extremely difficult to construct and high safety risk.In this paper,the deformation mechanism of Yangjiaping tunnel with small clear distance is analyzed based on the field test data.And summarized the surrounding rock reinforcement and replacement,optimization of support structure,process dislocation distance,non-blasting excavation methods to deal with the small clear distance and large deformation tunnel optimization measures,effectively strengthen the soft rock small clear distance and large deformation tunnel deformation control ability.