Blast monitoring: regulations, methods and control techniques

ROCK BREAKAGE:HARDNF_~S, ABRASION & WEAR blasting and blast designs to permit their fine tuning or optimization. -from Author 944252 Blast monitoring: regulations, methods and control techniques D. A. Anderson, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 95-110. This chapter deals with indirect engineering, specifically considering environmental effects o f blasting. The effects discussed here are ground vibration and air over-pressure or alrblast, collectively known as blast vibration (other effects, such as flyrock, dust and production of noxious or flammable gases in underground workings are not directly treated here). Blast vibrations may disturb surface structures such as houses, below ground structures such as pipelines, or the workings of underground mines. Emphasis is placed upon understanding problems and finding appropriate solutions. Though regulations must be complied with, existing control techniques to achieve compliance do not always properly address the problem. -from Author 944253 Blast vibration monitoring for rock engineering C . H . Dowding, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 111-135. This chapter summarizes the state-of-the-art in vibration measurement and structural response, to facilitate such an optimum blast design. Advances in earthquake engineering and nuclear blast protective design are transferred to blast vibration monitoring and control, while recent experimental observations of mining-induced ground motions and structural response axe summarized. Frequency of vibration and ground strain form the foundation for this presentation. The importance of frequency cannot be overestimated, as it is as critical as peak particle velocity in determining the response of above-ground structures. For below-ground structures, frequency, in combination with propagation velocity, controls response. -from Author

Machine excavation 944254 The mechanics of rock cutting R . J . Fowell, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 155-176. Though blasting is the natural choice for hard rock mineral production, the advantages of mechanical excavation are becoming increasingly attractive for many projects for the following reasons: economics; safety; ease of automation; accuracy; excavation walls remain undamaged; the product size can be handled by conveyors; and it has applications where there are limits on the level of vibrations allowed. In this chapter the types of machine employing drag picks and disk cutters are briefly reviewed, followed by a more detailed look at the mechanics of drag tool and disk cutter operations. Cutting tool materials and the influence of wear on performance are covered, along with a review of cuttability assessment and future developments. -from Author 944255 Theoretical and practical rules for mechanical rock excavation E . P . Deliac, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 177-227. A great deal of good work has been carried out to understand the mechanics of rock cutting and thus optimize both the design of machine specifications and that of the cutting tools. It is thus possible to provide a set of practical rules as to the design and selection of excavating equipment, based on theoretical and rational work well validated from thorough experiments. The purpose of this chapter is therefore to give an outline of these methods, starting with a logical approach to evaluate the performance of a given machine m a given rock environment. -from Author 944256 Database of TBM projects u n d e r t a k e n between 1950 and 1990 and an assessment of associated r o u n d - s t r e n g t h limitations • F. Howaxth, Tunnelling & Underground Space Technology, 9(2), 1994, pp 209-213.

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A review of all major 'IBM projects from 1974 to 1990 has been undertaken and the results entered into a database. A similar database was prepared from information obtained from a principal "IBM manufacturer covering the period 1952 to 1990. The database includes information such as machine specifications, machine performance data,a tunnel specifications, and ground characteristics. The database can be used as a guide to gauge potential machine performance in a range of ground conditions and tunnel geometries. The review also indicates that cun'ent "IBM technology is limited to certain ground strength conditions. -Author

944257 Mehrfacheinsatze van Schilden a m Beispiel eines Hydroschildes (Multiple application of shields with the example of a s l u r r y shield) C. Becker, Felsbau, 12(1), 1994, pp 30-43. In ten German cities subway-tunnels were constructed with the use of shield machines; nine different diameters were the result. Criteria for shield reuse include the comparability of.the geological and hydrogeological setting as well as horizontal and vertical alignment with the influence on face support, dimensioning of the machine, number of stones per ring/positioning of rams and tools. As a result, the reuse of shield machines is rare, but the reuse of a complete machine is rare; the application o f components such as drive, erector or tra/Iors has a better future. -from English summary

944258 Neue Lose- und Ausbautechniken z u r maschinellen, ' F e r t i g u n g ' van Tunneln in d r u c k h a f t e m Fels (Novel-type cutting and s u p p o r t i n g techniques for the i n d u s t r i a / p r o d u c t i o n of tunnels in rock subjected to high stress) L. Baumann & U. Zischinsky, Felsbau, 12(1), 1994, pp 25-29. Presents a system providing notoriously good performance of TBM's combined with segmcntational lining not only in stable ground but also in solid rock subject to high stress. The system relies on following components: a tunneling machine using the undercutting technique which reduces the support lag at the heading, allows variable cross sections and consequently the adapation of the thickness of support to the rock properties; and yielding and pre-tensioned segmental linings. The setting and yielding forces of their ideal plastic characteristics are adapted to the rock properties. A comparable support of 8.3 m and 9.5 m diameters proved its usefulness in the hardcoal mining industry. Both components of the system presented may be separately used and combined with different techniques. -from English summary

Hardness, abrasion and wear

944259 The use of water jets for rock excavation M. Hood, in: Comprehensive rock engineering. Vol. 4, ed J.A. Hudson, (Pergamon), 1993, pp 229-260. The difficulty of cutting rocks with mechanical tools lies in the strength of the tool materials. One solution to this fundamental constraint on the use of mechanical tools is to a~hlY the energy necessary to cut the rock by some means r than through mechanical tools. Many different ads have been investigated, including thermal, chemical and erosional (using high pressure liquid jets). It is widely recognized that the use of high pressure water jets