GROUNDBORNE VIBRATION FROM MECHANIZED TUNNELLING WORKS

In an age when environmental considerations and rising land costs are restricting development on the ground surface, the use of underground space for transport and utility systems is increasingly seen as a desirable option. Unfortunately, while tunnels can reduce the environmental impacts of the completed schemes, tunnel construction can often cause temporary adverse effects which must be considered at the design stage. Two of these potential impacts are groundbome vibration and the associated problem of groundbome noise. This paper presents surface ground vibration data from a number of tunnelling sites studied by TRL Limited. Vibration data from various tunnelling operations within the tunnels are considered, permitting a comparison to be made of the potential intrusion caused by different tunnelling practices. The data are also compared with vibration levels generated during tunnel operation, and from sources on the ground surface. The data are qualified by comparison witl current accepted limits for damage and intrusion. The more recent data have also been analysed to predict levels of groundbome noise which may be generated in overlying domestic buildings, and the potential disturbance which this may cause is considered. These analyses provide empirical guidance which may be used to assess possible problems arising from groundborne vibration during mechanized tunnelling works. For the covering abstract see ITRD E116460.