地下连续墙成槽施工振动对邻近古建筑的影响

Research on Influence of Construction Vibration Due to Underground Diaphragm Excavation on Nearby Ancient Buildings

地下连续墙是地铁车站和明挖法隧道常见的围护结构形式。当地下连续墙在岩石中成槽施工时,破岩过程产生的振动可能会威胁周边的建、构筑物,尤其是古建筑物的安全。选取杭州市吴山广场地铁车站工程现场实测记录,分析冲击钻、铣槽机、旋挖钻三种常见成槽施工机械引起的振动特性和衰减规律。从施工机械振源处的初始振速来评估施工引起的振动,在竖直方向上,旋挖钻最大,铣槽机次之,冲击钻最小。而在水平方向上,旋挖钻最大,冲击钻次之,铣槽机最小。基于以上监测成果,计算了在临近典型石塔类古建筑物施工时的安全距离,结果表明所需安全距离,冲击钻最大、旋挖钻次之、铣槽机最小。建议当有类似石塔保护需求时,采用铣槽机结合旋挖钻进行地下连续墙成槽施工。

Diaphragm wall is a kind of typical temporary retaining structure for construction of metro stations and open-cut tunnels. When the trench of a diaphragm wall was drilled in rock, vibration was generated by rock fracturing, which might threaten the safty of adjacent structures, especially ancient buildings. Field monitoring records under construction of Wushan Square Metro Station in Hangzhou were selected. The characteristics of vibration and attenuation during wave propagation were analyzed for three common trench cutting machines: the impact drill, the slot milling machine and the rotary drill. Results showed that the initial vibration speed produced by the rotary drill in the vertical direction at the vibration source was maximum, the second was produced by the slot milling machine, and the smallest was produced by the impact drill. But in the horizontal direction, the rotary drill was the largest, the next was produced by the impact drill, and the smallest was produced by the slot milling machine. The results were applied in analysis of safe space between construction machinery and a typical ancient stone tower under tunnelling construction. The impact severity in descending order due to construction on adjacent towers was the rotary drill, the impact drill and the slot milling machine. Therefore, it was recommended the slot milling machine to be used, when there was a need to protect ancient stone towers.