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

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.