1、BS 6472-2:2008Guide to evaluation of human exposure to vibration in buildingsPart 2: Blast-induced vibrationICS 13.160NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicate
2、s when the document was last issued. BSI 2008ISBN 978 0 580 54383 8The following BSI references relate to the work on this standard:Committee reference GME/21Draft for comment 06/30113306/DCPublication historyFirst published June 2008Amendments issued since publicationAmd. no. Date Text affectedBS 6
3、472-2:2008 BSI 2008 iBS 6472-2:2008ContentsForeword ii1 Scope 12 Normative references 13 Terms and definitions 14 Measurement and prediction of vibration 25 Measurement and prediction of air overpressure 46 Satisfactory vibration magnitudes 67 Satisfactory air overpressure magnitudes 9AnnexesAnnex A
4、 (informative) Suggested format and content of an assessment report 11Annex B (informative) Derivation of the vibration prediction curve for a typical field site An example 12Bibliography 17List of figuresFigure 1 Site-specific scaled distance graph 4Figure B.1 Logarithm of the peak particle velocit
5、y as a function of the logarithm of the scaled distance with 50% and 90% confidence levels 16List of tablesTable 1 Maximum satisfactory magnitudes of vibration with respect to human response for up to three blast vibration events per day 8Table B.1 Data from measurements of blast vibrations 14Table
6、B.2 Example of data manipulation to derive regression line and confidence boundaries 15Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 17 and a back cover.BS 6472-2:2008ii BSI 2008ForewordPublishing informationThis part of BS 6472 was publishe
7、d by BSI and came into effect on 30 June 2008. It was prepared by Subcommittee GME/21/6, Human exposure to mechanical vibration and shock, under the authority of Technical Committee GME/21, Mechanical vibration, shock and condition monitoring. A list of organizations represented on this committee ca
8、n be obtained on request to its secretary.SupersessionTogether with BS 6472-1:2008 this part of BS 6472 supersedes BS 6472:1992, which is withdrawn.Information about this documentThis part of BS 6472 contains guidance on the assessment of human response to vibration not available in ISO 2631-2.BS 64
9、72-1 and BS 6272-2 contain additional guidance and take account of recent developments in the subject. The layout of the standards differs substantially from previous editions. These present versions are intended to be more logical and accessible in their presentation of human perception to vibratio
10、n. BS 6472-2 deals with the particular problems associated with periodic blasting within range of occupied buildings: the guidance is a formalization of established, widely recognized techniques common in industry. BS 6472-1 offers guidance on how people inside buildings respond to building vibratio
11、n other than from blasting.A bibliography of appropriate supporting data published elsewhere is included.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a Br
12、itish Standard cannot confer immunity from legal obligations.In particular, attention is drawn to the following statutory regulations and guidance notes.Control of Pollution Act 1974 1Town and Country Planning Act 1990 2Environmental Protection Act 1990 3Minerals Planning Guidance Note MPG9 4Mineral
13、s Planning Guidance Note MPG14 5Planning Advice Note PAN50, Annex D 6Minerals Technical Advice Note, MTAN (Wales) 1: Aggregates 7 BSI 2008 1BS 6472-2:20081 ScopeThis part of BS 6472 gives guidance on human exposure to blast-induced vibration in buildings. It is primarily applicable to blasting assoc
14、iated with mineral extraction. This part of BS 6472 might also be useful in assessing other forms of vibration that are caused by blasting, including when explosives are utilized in civil engineering works and in demolition activity. One-off explosive events such as bridge or building demolitions ar
15、e outside the scope of this document.This part of BS 6472 does not give guidance on the probability of equipment malfunction, building damage or injury to occupants in buildings subject to blast-induced vibration. Neither is guidance given on legal liability or vibration control and minimization. Ad
16、vice on damage risk is given in BS 7385.2 Normative referencesThe following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendmen
17、ts) applies.BS 6841, Guide to Measurement and evaluation of human exposure to whole-body mechanical vibration and repeated shock BS EN ISO 8041, Human response to vibration Measuring instrumentation3 Terms and definitionsFor the purposes of this British Standard, the following terms and definitions
18、apply.3.1 air overpressurepressure wave in the atmosphere produced by a detonation of explosivesNOTE 1 Air overpressure consists of both audible (noise) and inaudible (concussion) energy.NOTE 2 It is measured in pascals and usually reported in dB(lin).3.2 data scatterdistribution of measured results
19、3.3 lapse raterate of fall of temperature with heightNOTE Lapse rate is measured in Ckmp1.3.4 maximum instantaneous charge (MIC)maximum amount (kg) of explosive detonated on any one delay intervalNOTE A typical blast consists of a number of boreholes. It is usually the case that each borehole is det
20、onated individually by the use of detonators at specific delay intervals.BS 6472-2:20082 BSI 20083.5 scaled distanceslant distance between the blast and the receiver divided by the square root of the maximum instantaneous chargeNOTE Scaled distance is measured in mkgp0.5.3.6 slant distance3-D vector
21、 distance between the blast location and measurement position obtained from coordinates in east-west, north-south and vertical directionsNOTE Slant distance is measured in metres (m).4 Measurement and prediction of vibration4.1 Characteristics of blast-induced vibrationBlast-induced vibration is imp
22、ulsive in nature and a typical time history would be a rapid build-up to a peak followed by a decay which might or might not involve several cycles of vibration (depending on damping). In some cases, for example in some forms of underground mine blasting, there might be a number of such impulses in
23、one blast vibration event.The duration of an event at the point of measurement (typically one or two seconds) is dependent upon the magnitude of the blast, i.e. the number of delay intervals and explosive quantities, the method of detonation, separation distance and the intervening geology between t
24、he blast and the receiver.A typical blast consists of a number of boreholes into which are placed the necessary explosive charges. It is usually the case that each borehole is detonated individually by the use of a series of detonators each with differing inherent millisecond delays.Impulsive events
25、, such as blast-induced vibration, are generally measured in terms of unfiltered time histories of three component particle velocities from which the peak values can be identified.4.2 Measurement of vibrationFor blasting, the current practice is to measure the peak particle velocity (ppv) using velo
26、city transducers. Vibration measuring equipment or seismographs should be able typically to measure over the range 0.0001 msp1(0.1 mmsp1) to 0.1 msp1 (100 mm sp1) over the frequency range 4.5 Hz to 250 Hz. Results obtained might differ slightly among sets of equipment.Although velocity transducers a
27、re commonly used because they measure the desired parameters directly, other forms of instrumentation might be appropriate provided that the constant velocity characteristics can be derived.The typical range of vibration frequency for blast-induced vibration is from 5 Hz to 40 Hz. BSI 2008 3BS 6472-
28、2:2008Usually in the case of blast-induced vibration, measurements should be made outside the building on a well-founded hard surface as close to the building as possible. Alternatively transducers may be buried if no such surface is available. Guidance on appropriate methods of mounting transducers
29、 is available elsewhere 8.NOTE There might be occasions when measuring inside a property is necessary, for example, for public relations purposes.Since this British Standard is concerned with human response within buildings, the external levels are set so as to achieve satisfactory internal levels.C
30、alibration of equipment and traceability are important but outside the scope of this standard.4.3 Prediction of vibrationIn order to predict the likely vibration magnitude, a series of measurements at several locations should be taken from one or more trial blasts. The vibration measuring equipment
31、should be located in an approximate straight line in the propagation direction of interest. Depending on the number of directions of interest, the local geology and the availability of equipment, several trial blasts might be needed. Scaled distance graphs can then be prepared for each direction of
32、interest. The ppv in the three translational axes should be measured in mmsp1and the maximum component of the vibration identified for each measurement location.The values should then be plotted against scaled distance on logarithmic scales where the scaled distance, s, is as follows:Where:d is the
33、slant distance from the blast in m;C is the MIC in kilograms.A graph similar to that shown in Figure 1 should result, specific to each site under consideration. The graph can then be used to indicate the likely vibration magnitudes at a given distance for a given MIC. Differing geology and changes i
34、n blast design 9 result in data scatter and this should be taken into account in determining an adequate number of data points. Vibration limits should be expressed as a statistical average to take account of the data scatter.The scaled distance approach can be a great help in designing blasts to ac
35、hieve specific magnitudes of vibration at specific locations.EXAMPLEIf the ppv limit is to be 6 mmsp1for 90% of the blasts and the MIC is 100 kg then from Figure 1 it can be seen that the scaled distance value on the 90% line at 6 mmsp1is 65 mkgp0.5. This means that the slant distance d can be deduc
36、ed from the following equation Where s is the scaled distance and C is the MIC.Hence d is 650 m./sd C=/sd C=BS 6472-2:20084 BSI 2008Similarly, if the vibration limit and slant distance are known then the MIC can be calculated.The scaled distance data should be kept under regular review as blast moni
37、toring continues through the operation of the site and the data set increases.5 Measurement and prediction of air overpressure5.1 GeneralWhenever blasting is carried out energy is transmitted from the blast site in the form of airborne pressure waves. These pressure waves comprise energy over a wide
38、 range of frequencies, some of which are at frequencies higher than 20 Hz and are, therefore, perceived as sound. The majority of the airborne energy is carried at frequencies below 20 Hz and hence is inaudible to the human ear, but can be sensed as concussion or pressure. It is the combination of t
39、he sound and concussion that is known as air overpressure. Any attenuation due to the topography, either natural or man-made, between the blast and the receiver is much greater for the audible higher frequency components of the pressure wave, with the lower frequency components being largely unaffec
40、ted. The amount of energy transmitted in the audible part is relatively small compared with that transmitted in the inaudible part. Baffles, mounds and other acoustic screening techniques do not significantly reduce air overpressure levels.Figure 1 Site-specific scaled distance graph1001011010050% c
41、onfidence level90% confidence levelScaled distance (m kg )-0.5Peak particle velocity (mm s )-1 BSI 2008 5BS 6472-2:2008Air overpressure can excite secondary vibrations at audible frequencies in buildings and it is often this effect that gives rise to adverse comments from the occupiers. There is no
42、known evidence of structural damage occurring in the United Kingdom as a result of air overpressure levels from blasting associated with mineral extraction. The highest levels normally measured in the United Kingdom are generally less than 1% of the levels known to cause structural damage 10.The pro
43、pagation velocity of air overpressure is at the speed of sound in air, i.e. about 340 msp1and therefore it travels significantly slower than its associated ground-borne vibration.This results in the air overpressure always arriving after the ground vibration onset and by several seconds if large dis
44、tances are involved. Nevertheless, it is not readily possible for an observer to differentiate between these two sources and their respective effects and so any air overpressure significantly adds to the overall subjective blast experience.5.2 Measurement of air overpressureIt is essential that the
45、equipment used to measure air overpressure has an adequate low frequency response to capture fully the dominant low frequency component. It is for this reason that air overpressure magnitudes are measured using linear response, dB(lin), rather than with an A weighting, dB(A), as normally used in noi
46、se measurements. A 2 Hz high-pass system with an almost flat response down to 2 Hz should be used. If measurements include frequencies of less than 2 Hz they can be greatly distorted by even the slightest pressure changes, which can be caused by the gentlest of wind or people walking past the microp
47、hone.5.3 Prediction of air overpressureAccurate prediction of air overpressure is almost impossible due to the variable effects of the prevailing weather conditions and the large distances often involved.Meteorological conditions, including air temperature, lapse rate, cloud cover, humidity, wind sp
48、eed, direction and turbulence can all affect the magnitude of the air overpressure at any single location. Certain atmospheric conditions can produce a localized enhancement of the air overpressure in one direction. Data can be obtained from the nearest meteorological office, the lapse rate can be g
49、raphed and the risk of enhancement can be assessed. However, in practice these data are commonly obtained at some distance (often many kilometres) from the blast site and up to several hours before the detonation. Consequently the relevance of the data, and hence any prediction, could be doubtful for the location and time of blast, and the accuracy further reduced by the variability of the British weather 9. Control of air overpressure should always be by its minimization at source through appropriate bl
