Environmental factors have become increasingly restrictive and review of the levels of vibrations deemed acceptable by standardising authorities abroad reveals a general lowering of permissible limits. This trend is not supported by new field evidence of damage at lower particle velocities and indicates a change in social climate rather than a change in engineering values. However, it must be accepted that tighter vibration controls on works are likely to be required and that trials during the site investigations are often necessary for construction works where explosives are involved. The correct choice of instrumentation is crucial to the success of vibration monitoring at construction sites. Each link must be considered individually in terms of amplitude capacity and frequency response. Other factors such as robustness, ease of use, reliability and cost must also be taken into account. It is important that the results of vibration measurements are evaluated by experienced geotechnical engineers as the interaction of vibration and structures within or founded upon soil or rock is often very complex. The careful measurement of vibration during blasting operations can lead to cost saving and other benefits resulting from the following factors: (a) predictions made on the basis of trial blasting will allow the Contractor to determine if, and to what extent, restrictions to the amount of explosive detonated instantaneously will inhibit his methods; (b) the ready availability of detailed vibration records may suggest improvements to the blasting method; (c) the Engineer will have a sound basis for his decisions regarding permissions for future firing by the Contractor; and (d) full vibration records will assist the assessment of any damage or intrusion claims by third parties. At locations close to the explosive source the frequency of the motions is likely to be higher than can reliably be measured with many automatic vibration measuring systems which were often designed to monitor quarry blasting at relatively large ranges. This will be particularly true when small charges are fired in strong rocks. The consideration of potential hazard from vibration at an early stage of the planning will determine the desirability of trial blasting during the site investigation programme. Analysis of trial blast data should enable a specification for the equipment to be used during the works to be drawn up and given in the contract documents. In some circumstances it is possible to wrongly attribute damage caused by construction-induced ground deformations to vibration, so where excavations are taking place close to buildings it may be advisable to monitor both ground deformation and vibration. It will also be useful to acquire records of embient vibration levels at particular sites. These will often be very revealing and allow the construction induced vibration to be considered in its proper context. (Author/TRRL)

  • Availability:
  • Corporate Authors:

    Transport and Road Research Laboratory (TRRL)

    Wokingham, Berkshire  United Kingdom 
  • Authors:
    • NEW, B M
  • Publication Date: 1990


  • English

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Filing Info

  • Accession Number: 00612231
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Files: ITRD, TRIS
  • Created Date: Aug 31 1991 12:00AM