Prediction and Control of Vibrations Induced by Shield Tunneling in Hard Rock Strata for Conservation of the White Tower

Environmental vibrations caused by shield tunneling in hard rock strata can have adverse effects on neighboring cultural heritage buildings. In response to the challenges posed by the complex vibration sources from shield tunneling in hard rock, stringent vibration criteria for cultural heritage preservation, as well as the poor overall structural integrity, a vibration back-analysis method based on field measurements and finite element method is proposed. This method is also applied for prediction and control technology of vibrations induced by shield tunneling in hard rock strata for conservation of the White Tower in the Zhijiang Road water conveyance pipe gallery tunnel project. The vibration isolation effects are also analyzed focusing on two aspects, namely shield construction parameters and PVC hollow pile barriers. It is concluded that the main vibration source due to shield tunneling in hard rock strata is caused by the rotation of the cutter head and the cutting of hard rock by the disc cutters. There is a good correlation between excavation speed and tunneling-induced vibration level. Thus reducing the excavation speed significantly decreases vibration level over the concerned frequency range. The PVC hollow pile has a good vibration reduction effect in the mid-to-high frequency range, with an average vibration reduction rate of up to 50% within the White Tower area.