超浅埋特大断面小净距隧道开挖爆破对景区影响的分析

UMERICAL ANALYSIS OF THE IMPACT OF EXCAVATION BLASTING ON THE FUDAO SCENIC AREA IN A SUPER SHALLOW BURIED SUPER LARGE SECTION SMALL CLEAR DISTANCE TUNNEL

超浅埋隧道施工极易影响地表及邻近建构(筑)物。福州市某特大断面小净距隧道穿越城市景区,紧邻景区钢桁架架空桥梁森林步道。如何避免开挖爆破施工对景区及其敏感建构(筑)物造成较大影响,是工程建设亟待解决的难题。利用midas GTS软件建立了福道钢桁架桥简化模型,模拟了隧道开挖爆破施工对景区地表及钢桁架桥的影响,并与现场实测进行了对比分析。计算分析表明,在推荐的爆破方案下:(1)质点振动速度在距离爆心较近时迅速衰减,但衰减幅度在距离爆心较远时减缓;(2)景区地表及福道钢桁架桥面最大振速均能满足爆破振速控制标准;(3)爆破施工对景区影响甚微,为该工程的设计与施工提供了依据和指导。

The construction of ultra shallow buried tunnels can easily affect the surface and adjacent buildings.A super large section small clearance tunnel in Fuzhou passes through an urban scenic area,adjacent to a steel truss overhead bridge and forest walkway in the scenic area.How to avoid the significant impact of excavation and blasting construction on scenic areas and sensitive buildings is an urgent problem to be solved in engineering construction.A simplified model of Fudao steel truss bridge was established using midas GTS software,and the impact of tunnel excavation blasting construction on the surface of the scenic area and the steel truss bridge was simulated and compared with on-site measurements.The calculation analysis shows that under the recommended blasting scheme:(1)The particle vibration velocity rapidly decays when close to the blasting center,but the attenuation amplitude slows down when far away from the blasting center;(2)The maximum vibration speed of the surface and Fudao steel truss bridge deck in the scenic area can meet the blasting vibration speed control standards;(3)The impact of blasting construction on the scenic area is minimal,providing a basis and guidance for the design and construction of the project.