TRAIL AND CONSTRUCTION INDUCED BLASTING VIBRATION AT THE PENMAENBACH ROAD TUNNEL

This report provides details of the vibrations caused by the explosive excavation of rock for the penmaenbach tunnel which forms part of the a55 North Wales coast road improvement scheme. In particular comparison is made between predictions from blasting trials (by the transport and Road Research Laboratory) and the vibrations actually measured during construction. The 'upper bound' vibration prediction established during the site investigation was proven an accurate working guide. However, variations in the pyrotechnic delay elements of the longer delay detonators caused vibration levels to be generally lower than expected and this effect is investigated and explained. The analysis and presentation of the vibration is discussed and the advantages of multiple regression techniques are apparent when data are not reasonably characterised by traditional 'square' or 'cube root' scaling methods. The factors which influence the input and propagation of energy from explosive sources are discussed in the context of conditions prevailing during construction works in general. The frequency distribution of the vibration is presented for various ranges during the trial, tunnelling and pre-splitting rounds. The frequency domain analysis showed that, at locations within 50 m of the charges, frequencies well in excess of 200 hz were present and the implications of this finding on the specification of site measuring equipment are given. (a)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/02665247
• Corporate Authors:

  Transport and Road Research Laboratory (TRRL)

  Wokingham, Berkshire  United Kingdom 
• Authors:
  • NEW, B M
• Publication Date: 1989

Language

• English

Media Info

• Pagination: 11 p.
• Serial:
  • TRRL RESEARCH REPORT
  • Issue Number: RR 1
  • Publisher: Transport and Road Research Laboratory (TRRL)
  • ISSN: 0266-5247

Subject/Index Terms

• TRT Terms: Excavation; Excavations; Forecasting; Mathematical analysis; Measurement; Presplitting (Blasting); Regression analysis; Tunnels; Vibration
• Geographic Terms: United Kingdom
• Subject Areas: Bridges and other structures; Data and Information Technology;

Filing Info

• Accession Number: 00487858
• Record Type: Publication
• Source Agency: Transport and Road Research Laboratory (TRRL)
• Report/Paper Numbers: 81
• Files: ITRD, TRIS
• Created Date: Sep 30 1989 12:00AM