外文翻译-民用工程目的岩爆地震载荷模型.doc

1、第147页翻译部分英文原文ORIGINAL RESEARCH PAPERHow to model rockburst seismic loads for civil engineering purposes?Zbigniew ZembatyReceived: 23 May 2010 / Accepted: 7 April 2011 / Published online: 22 April 2011 The Author(s) 2011. This article is published with open access at SAbstract： Usually rockbursts fro

2、m underground mining induce minor quakes of MM intensity up to V. Sometimes however the surface tremors reach level of MM epicentral intensityI0=VI to VIII. Since a fast industrial development often takes place in the mining areas then some seismic design rules for new buildings are needed. The main

3、 obstacle is then lack of respective design response spectrum and an unclear definition of the level of design acceleration to apply. Particularly the latter one is difficult to overcome because the rockburst ground motion records differ from natural earthquakes when it comes to their spectral prope

4、rties as well as return periods. This paper presents a method how to rationally define the design acceleration so that a seismic code, e,g, Eurocode 8, can be applied in practical design procedures in the mining areas.Keywords： Mine tremors Rockbursts Ground motion Response spectra Seismic codes1 In

5、troductionThere are many types of ground motion other than earthquakes: blasts from queries induce waves in the ground which radiate hundreds and thousands of meters away from the source,exciting building vibrations (see e.g. Dowding 1996; Khandelwal and Singh 2007), traffic vibrations excite buildi

6、ngs in the vicinity of roads or railways (e.g. Paolucci and Spinelli2006), rockbursts originating from deep mining or reservoir induced seismicity (Knoll 1992;Gibowicz and Kijko 1994) also produce ground motion. They occur randomly after large volumes of ground are excavated during reservoir constru

7、ction. The strongest rockbursts from deep mining also occur randomly but sometimes may also be triggered purposely by special, initiating blasts. Some of these motions may damage structures when they are unusually intensive. These from queries or surface mining are well studied and analyzed in the b

8、ook by Dowding (1996).On the other hand large, deep mining rockburst effects are not as well studied, though they can be of much greater maximum intensity than the blast induced ground motion. The strongest rockbursts often reach magnitude ML = 4 and sometimes may even exceed ML = 5. These strongest

9、 rockbursts are listed among natural earthquakes by USGS National Earthquake Information Center in Denver (http:/neic.usgs.gov) and are subject of careful analyses to differentiate them from underground nuclear explosions (see e.g. Pomeroy et al. 1982). Such magnitude with the focal depth of 12km ma

10、y lead to epicentral intensities of MM VI to VIII. Since the vicinity of deep underground mines is often a place of intensive construction activities the problem of assessing seismic risk (see e.g. Van Eck et al. 2006) and mitigating these effects on civil engineering structures becomes important. S

11、eismic codes (e.g. Eurocode8, 2005) are devoted to natural earthquakes which differ in many respects from rockburst ground motion. This paper proposes a simple method to modify the Eurocode 8 approach to include rockburst quakes, so that a rational seismic load can be defined for civil engineering p

12、urposes.The main problem is the definition of the so called design acceleration. Deep mining and the assocated return period of the extreme tremors, used in the analyses of rockbursts, differs substantially from earthquakes which makes it impossible to use the same probabilistic approach as for the

13、classic seismic risk analyses. Thus the main purpose of this paper is to present a method of assigning level of design acceleration for rockbursts which would be consistent with seismic code earthquake intensity level. The approach to modify Eurocode 8is described in detail.2 Rockbursts and measures

14、 of their intensity on the ground surfaceThere are various mechanisms of rockbursts. Generally they occur when accumulated stress from advancing mine activity, fractures rock mass. It is possible that the strongest rockbursts, which are of primary interest in this paper, are minor earthquakes induce

15、d on nearby fault by extensive mining activity. See Johnston (1992) or the monograph by Gibowicz and Kijko (1994) for explanations of the rockburst origin in technological and seismological terms. Others have compared ground motion from the largest mine induced seismicity to ground motion from an un

16、derground nuclear explosion, where the seismological mechanism resembles a shallow earthquake (Gibowicz and Kijko 1994). Typical damage to the buildings, infrastructure or equipment at or nearest epicenter include furniture toppling, damages to the lifts, characteristic structural and cosmetic cracks of the masonry buildings, cracks of the panel prefabricated buildings, and in some cases even stronger damages of the