In the heart of Hangzhou, China, a delicate dance is unfolding between modern infrastructure development and the preservation of cultural heritage. The White Tower, a historic landmark, stands as a silent sentinel amidst the bustling urban landscape, while beneath its foundations, a new tunnel is being carved through hard rock strata. The challenge? Ensuring that the vibrations from shield tunneling do not disturb the ancient structure.
A team of researchers, led by CAI Yuanqiang from the College of Civil Engineering at Zhejiang University of Technology, has been tackling this very issue. Their work, published in the journal *Yantu gongcheng xuebao* (translated to English as “Geotechnical Engineering”), offers a novel approach to predicting and controlling vibrations induced by shield tunneling in hard rock strata.
The team’s innovative method combines field measurements with the finite element method, creating a vibration back-analysis technique tailored to the complex vibration sources generated by shield tunneling in hard rock. “The main vibration source is the rotation of the cutter head and the cutting of hard rock by the disc cutters,” explains CAI. “We found a good correlation between excavation speed and tunneling-induced vibration level. Reducing the excavation speed significantly decreases the vibration level over the concerned frequency range.”
The implications for the energy sector are substantial. As urban areas continue to expand, the need for underground infrastructure—such as tunnels for water conveyance, transportation, and energy distribution—grows. In cities with historic buildings, the ability to predict and control vibrations is crucial. “Our research provides a practical tool for engineers to mitigate the risk of damage to cultural heritage sites during tunneling projects,” says CAI.
The team also explored the use of PVC hollow pile barriers as a vibration isolation measure. Their findings revealed that these barriers have a notable 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. This discovery could pave the way for more effective and efficient vibration control methods in future tunneling projects.
The research not only addresses immediate concerns but also sets the stage for future developments. As cities worldwide grapple with the balance between modernization and preservation, the techniques developed by CAI and his team offer a promising solution. By understanding and controlling the vibrations induced by shield tunneling, we can protect our cultural heritage while advancing infrastructure development.
In the words of CAI, “This research is a step towards harmonizing the old and the new, ensuring that our pursuit of progress does not come at the cost of our shared history.” As the White Tower stands unharmed, the lessons learned from this project will echo through the tunnels of time, guiding future endeavors in the construction and energy sectors.