Determination of blast-induced ground vibration equations for rocks using mechanical and geological properties

Abstract In an effort to assess state of the art methodologies for the experimental determination of modal characteristics, 12 European groups, most of them working in the area of aircraft ground vibration tests for flutter certification, participated in a GAR-TEUR action group whose main activity was to have independent tests of a single representative structure. Design considerations for the common structure are first detailed. Estimates of frequency response functions and modal characteristics are then compared and show a level of consistency that is much higher than those reported in previous similar exercises.

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Investigating ground vibration to calculate the permissible charge weight for blasting operations of Gotvand-Olya dam underground structures / Badania drgań gruntu w celu określenia dopuszczalnego ciężaru ładunku wybuchowego przy pracach strzałowych w podziemnych elementach tamy w Gotvand-Olya

Archives of Mining Sciences ◽

10.2478/v10267-012-0044-z ◽

2012 ◽

Vol 57 (3) ◽

pp. 687-697 ◽

Cited By ~ 2

Author(s):

Saeed Soltani-Mohammadi ◽

Hassan Bakhshandeh Amnieh ◽

Moein Bahadori

Keyword(s):

Minimum Distance ◽

Hybrid Methods ◽

Ground Vibration ◽

Charge Weight ◽

Underground Structures ◽

Scaled Distance ◽

Maximum Charge ◽

Safe Level ◽

Surrounding Environment

Abstract Ground vibration, air vibration, fly rock, undesirable displacement and fragmentation are some inevitable side effects of blasting operations that can cause serious damage to the surrounding environment. Peak Particle Velocity (PPV) is the main criterion in the assessment of the amount of damage caused by ground vibration. There are different standards for the determination of the safe level of the PPV. To calculate the permissible amount of the explosive to control the damage to the underground structures of Gotvand Olya dam, use was made of sixteen 3-component (totally 48) records generated from 4 blasts. These operations were recorded in 3 directions (radial, transverse and vertical) by four PG-2002 seismographs having GS-11D 3-component seismometers and the records were analyzed with the help of the DADISP software. To predict the PPV, use was made of the scaled distance and the Simulated Annealing (SA) hybrid methods. Using the scaled distance resulted in a relation for the prediction of the PPV; the precision of the relation was then increased to 0.94 with the help of the SA hybrid method. Relying on the high correlation of this relation and considering a minimum distance of 56.2 m to the center of the blast site and a permissible PPV of 178 mm/s (for a 2-day old concrete), the maximum charge weight per delay came out to be 212 Kg.

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Evaluation on Filter Performance of Variational Mode Decomposition and Its Application in Separating Closely Spaced Modes

Shock and Vibration ◽

10.1155/2020/7605683 ◽

2020 ◽

Vol 2020 ◽

pp. 1-16

Author(s):

Wenjing Gu ◽

Li Zhou

Keyword(s):

Wavelet Packet ◽

Ground Vibration ◽

Signal Decomposition ◽

Variational Mode Decomposition ◽

Filter Performance ◽

Mode Decomposition ◽

Oscillation Modes ◽

Modes Of Vibration ◽

Two Degree Of Freedom

The equivalent filter characteristics of variational mode decomposition (VMD) are fully evaluated when applied to the fractional Gaussian noise (fGn) and the application in separating closely spaced modes of vibration system is performed in this paper. VMD is a newly proposed signal decomposition technique, which nonrecursively decomposes a signal into a given number of subsignals (modes), and each mode is mostly compact around a center pulsation. The filter performance of VMD is largely dependent on the constraint parameter and the initialization of center frequencies. In order to extract the desired modes, criteria for the determination of decomposition parameters are established. The initial center frequencies could be simply determined by prior estimated modal frequencies of the analyzed signal, while the constraint parameter is optimized utilizing a genetic algorithm (GA). A two-degree-of-freedom parametric system is considered to evaluate the capability of VMD in the separation of closely spaced modes. Compared with the noise-assisted versions of empirical mode decomposition (EMD) and wavelet packet transform (WPT), the parameter-optimized VMD can successfully separate the closely spaced modes while recovering the most modal information simultaneously. When introduced to the ground vibration test (GVT) of a horizontal tail, the proposed method successfully extracted the first five oscillation modes and identified the modal parameters accurately.

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Galactic orbits of stars

Symposium - International Astronomical Union ◽

10.1017/s0074180900105340 ◽

1966 ◽

Vol 25 ◽

pp. 93-97

Author(s):

Richard Woolley

Keyword(s):

Globular Cluster ◽

Potential Field ◽

High Velocity ◽

Velocity Vector ◽

Variable Stars ◽

The Sun ◽

Proper Motions ◽

Rr Lyrae ◽

The Galaxy

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.

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Distance to SN 1987A and the LMC

Symposium - International Astronomical Union ◽

10.1017/s0074180900118959 ◽

1999 ◽

Vol 190 ◽

pp. 549-554

Author(s):

Nino Panagia

Keyword(s):

Angular Size ◽

Large Magellanic Cloud ◽

Magellanic Cloud ◽

Light Curves ◽

Distance Modulus ◽

Absolute Size ◽

Sn 1987A

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.

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International determination of the total motion of the pole

Symposium - International Astronomical Union ◽

10.1017/s0074180900177824 ◽

1961 ◽

Vol 13 ◽

pp. 29-41

Author(s):

Wm. Markowitz

Keyword(s):

Secular Motion ◽

The Future

A symposium on the future of the International Latitude Service (I. L. S.) is to be held in Helsinki in July 1960. My report for the symposium consists of two parts. Part I, denoded (Mk I) was published [1] earlier in 1960 under the title “Latitude and Longitude, and the Secular Motion of the Pole”. Part II is the present paper, denoded (Mk II).

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Time and Latitude in South Africa

International Astronomical Union Colloquium ◽

10.1017/s0252921100026816 ◽

1972 ◽

Vol 1 ◽

pp. 27-38

Author(s):

J. Hers

Keyword(s):

South Africa ◽

Cape Town ◽

Astronomical Observations ◽

Royal Observatory ◽

The Republic ◽

Astronomical Determination ◽

Limited Accuracy ◽

Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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