Dear Label_Name,

Greetings! I hope you are well.

I am writing on behalf of an international publishing house, Science and Education Publishing, USA (http://www.sciepub.com).

Science and Education Publishing (SciEP) is a multidisciplinary open access publisher of Journals covering the fields of Science, Technology and Medicine. All SciEP publications are subject to high-quality peer review, editorial and production processes and are freely available online.

Welcome to the April, 2013 edition of SciEP newsletter, providing monthly summaries of articles on science & education related topics of interest to scientist and professionals. The mission of our journals is to provide an open access forum for publishing new findings on issues pertinent to scientific and academic field. We also invite you to submit original research papers, review articles, short reports, or case studies are considered for publication in our Multidisciplinary Journals.

American Journal of Public Health Research
DOI: 10.12691/ajphr-1-1-3

The Implementation of a Tele-Homecare System with Service Oriented Architecture and HL7 Message Transmission Standard
Ching-Sung Wang

American Journal of Medical and Biological Research
DOI: 10.12691/ajmbr-1-1-2

The Influence of Ethanol on Pyruvate Kinases Activity in Vivo, in Vitro, in Silico
Lelevich Sergey Vladimirovich, Khrustalev Vladislav Victorovich, Barkovsky Eugene Victorovich, Shedogubova Tatyana Aleksandrovna

American Journal of Medical Sciences and Medicine
DOI: 10.12691/ajmsm-1-1-1

Clinical and Histological Features in Wegener Granulomatosis
Li Cavoli Gioacchino, Passantino Rita, Bono Luisa, Tortorici Calogera, Ferrantelli Angelo, Giammarresi Carlo, Rotolo Ugo

American Journal of Infectious Diseases and Microbiology
DOI: 10.12691/ajidm-1-1-2

The Curse of Lymphatic Filariasis: Would the Continual Use of Diethylcarbamazine Eliminate this Scourge in Papua New Guinea?
Anne Lanham, Lillian Mwanri

We have released issues of some journals on February 2013.
American Journal of Public Health Research
American Journal of Medical Sciences and Medicine
American Journal of Medical and Biological Research
American Journal of Pharmacological Sciences
American Journal of Clinical Medicine Research
American Journal of Nursing Research
American Journal of Cancer Prevention
American Journal of Medicine Studies
American Journal of Infectious Diseases and Microbiology
American Journal of Cardiovascular Disease Research
American Journal of Biomedical Research
American Journal of Mechanical Engineering
American Journal of Microbiological Research
Journal of Preventive Medicine
American Journal of Food and Nutrition
American Journal of Hypertension Research
American Journal of Sports Science and Medicine
Journal of Cancer Research and Treatment
American Journal of Zoological Research
Journal of Biomedical Engineering and Technology
American Journal of Microbiological Research
Biomedical Science and Engineering

We are pleased to announce that submissions are now being accepted for peer review for all the journals across all our subject areas in SciEP.

Please submit your manuscript via our online submission system:
http://www.sciepub.com/author/signin

To unsubscribe from our mailing list, please click on the following link: unsubscribe

I am looking forward to hearing from you.

Kind regards,

David Rain
Email:join@sciepub.com
Science and Education Publishing (http://www.sciepub.com)

Seismic Waves Distribution from Blasting in a Rock Massif with One Crack or System of Parallel Fissures

Viktor Boiko

Department of Mining and Geotechnical Engineering, Special Design-Engineering Bureau GEOPHYSICIST, Scientific-Production Enterprise, Kiev, Ukraine

Abstract: Explosive action of cylindrical charge was studied in an anisotropic rock massif which contain cracks or system of parallel fissures. Sound wave theory was used for qualitative pattern of seismic wave distribution around blasting. Results show changing of seismic waves from round to elliptical shape during distribution through rock massif with cracks.

Keywords: blasting, charge, seismic wave, crack, rock massif, seismic hazard, rock mechanics

Citation: Viktor Boiko, Seismic Waves Distribution from Blasting in a Rock Massif with One Crack or System of Parallel Fissures. American Journal of Civil Engineering and Architecture, 4 (2). 50-53. January 2016. doi:10.12691/ajcea-4-2-2

1. Introduction

Problem of seismic safety from blasting is sharp for open pit mining and civil engineering. Very often for simplifying calculation ideal isotropic medium and sphere shape charge are taken during blast design. [1,2,3,4,18] It took place in Normative Documents and Codes. The seismic safety radius is used everywhere. However, in real life we do not have ideal conditions during blasting. Real massif has fissures and it does not have same properties in all directions. In practice, if we build lines of equal velocity for oscillation process we would have ellipsoid, not circle. Such results are shown by hundreds and hundreds of measurement data. That is why seismic safety calculation need to be improve and approximated to reality. It is need to study field of equal particle velocities in rock massif with cracks.

Very deep research in this topic was provided and interesting results were received in Geophysics and Earthquake Engineering. [20,21] Models of wave propagation in the elastic medium with cracks were built on the basis of an extension of effective medium Hudson's theory, finite element method, etc. But amplitude-frequency characteristics of seismic waves from earthquakes and explosions are different [22] and research for blasting seismic should be done.

2. Materials and Methods

Investigation of wave field distributional pattern from blasting carried out by taking approximated medium model to real anisotropic massif. Homogenous and endless medium was taken as a basis model. One crack or a systems of parallel fissures with different characteristics were accepted depends of task type. Physical-mechanical properties of crack filler were different from medium properties. Blasting of cylindrical charge was taken as dynamic influence.

Detonation of charge along its length was taken as instant and seismic wave studied on big distant from explosion. All wave types, which are produced form blasting, are characterized small amplitude. Task is to find just qualitative pattern of seismic wave distribution around blasting. That is why we could use sound wave theory. [5,6,7,8,9].

To simplify problem solving of this task consider case when seismic wave from vertical charge goes through fissure. Axial of this charge is parallel to crack plane. Origin of coordinates placed on border of fissure on the opposite side to charge on the smallest distance from the one. Axial ОХ was parallel and axial OZ was perpendicular to crack plane (Figure 1) Charge (Q) in plane XOZ has coordinates , , where is fissure width, is a distance from charge to fissure. [10,11,12,13,14].

Let’s consider a case . Part of medium, which located beyond of fissure, takes as first (1), before of crack take as third (3), in the middle – as second (2) and consider that incident wave is sinusoidal. In this case we use Brekhovskikh’s formula [19], pressure in this wave could be written down as:

[picture] | (1)

– pressure in the points, which are located on the distance from charge with radius ;

– imaginary value;

– magnitude of propagation vector, ;

– wave length;

–frequency of vibration (cyclic);

– anger of incidence wave;

– time.

 – distance from charge to viewpoint of medium with coordinates , :

[picture] | (2)

Figure 1. Seismic wave passing through fissure from blasting of vertical borehole charge

Along with down coming wave in the medium, reflected pressure wave arises behind the crack. [15,16,17]

[picture] | (3)

Complex reflection coefficient is inputted in the first part of equality (3). It is expressed through impedances of examined medium parts.

[picture] | (4)

де –density of medium 1, 2, 3;

– wave distribution velocity in these mediums.

As far as crack is thin then condition is met

[picture] | (5)

Whence

[picture] | (6)

Pressure in the wave which came in medium 1 could be calculated due to transparence coefficient:

[picture] | (7)

Transparence coefficient might be represented through impedances і :

[picture] | (8)

The dependence of the magnitude of the pressure was taken into account during the mass velocity U determining in the environment for a crack in general formula:

[picture] | (9)

Expressions (1), (3), (9) give

[picture] | (10)

Hence the value of mass velocity:

[picture] | (11)

With help of (7) the (11) could be written down as:

[picture] | (12)

Formula (12) with (8) gives opportunity to calculate square modulus of transparency ratio:

[picture] | (13)

The resulting expression (13) might be converted using identity . Than:

[picture] | (14)

Let’s confine ourselves to the consideration of incidence angles for which

[picture] | (15)

That is . After a series of expansions of in formula

[picture] | (16)

with , equation (14) looks like

[picture] | (17)

Based on the above, the mass velocity of the wave calculated by the formula:

[picture] | (18)

We accepted that the crack width d and the impedance difference z1 – z2 heading to zero in the isotropic medium. Then, based on dependencies (4) and (17) it can be written that

[picture] | (19)

A fallen on the crack mass velocity (18) takes the form of:

[picture] | (20)

Consider the case of the seismic waves falling at a distance R from the charge when the wavelength is bigger more than the distance а between parallel cracks: and (Figure 2).

Figure 2. The scheme of seismic waves distribution in anisotropic medium with parallel fracture system

Parameters of cracks and filler of environment can be considered the same for all fissures which are plane parallel and thin: . Medium between the cracks is taken homogeneous and isotropic. Values that characterize them are marked by index 1, medium variables (aggregate) - by index 2. If crack are numbered in the distance from the charge Q, assuming that the charge is located at the 0th crack and (Figure 2), the number of cracks can be determined by the formula:

[picture] | (21)

where – the angle between the direction to the observation point M and the normal to the crack (the angle of the blast wave falling on the crack). If then .

Problem field involves the study of mass velocity fluctuations in the points of medium, which are separated from charging more cracks number.

Using expression (18) for each series of cracks between charge Q and the point M , we obtain the formula for determining the mass velocity at the point of the medium:

[picture] | (22)

Using (3.21), we have:

[picture] | (23)

Isoseismic line is characterized by the same mass velocity, it is mean that:

[picture] | (24)

in the direction perpendicular to the exposed cracks (where ) isoseismic line is located in the distance R0 from the source of explosion (Figure 3). Distance from anywhere isoseismic line when taking into account the expressions ( 23) and ( 24 ) is defined as

[picture] | (25)

Equation (18) (23) (25) describe the distribution of seismic waves in the rock with cracks. Using these equations by the inverse problem of frequency analysis of incident and reflected waves can be solved, rocks structure and factor anisotropy can be determined. Distances to isoseismal line in the fractured massif around the explosion are defined by the formula (25) and obtained their distribution pattern is shown in Figure 3.

Figure 3. Seismic waves distribution in fractured massif around the explosion

3. Results and Conclusion

Numerical data analysis shows that the border isoseismic lines varies from elliptical shapes to form a circle. It was found that modifying of the isoseismic lines has an impact parameter which is included in the formula (25).

When specified parameter is decreasing the elliptical shape isoseismic lines moves in a circle shape. This transition should be expected in the peripheral area of the explosion because of high-frequency components are damping with increasing distance from the explosion to the observation point in the oscillation spectrum. Analytical proof of this fact is the decrease parameter when and .

Cracks are not parallel in a real massif, they are not filled, or filled unevenly. That is why theoretical research results may differ from experimental data. However, results of this article shows that crack influence on the shape of seismic waves. Understanding of the impact can help to predict seismic hazard from blasting and to control waves for best using the energy of explosions.

References

[1]   | Ricardo Resende. An Investigation of Stress Wave Propagation Through Rock Joints and Rock Masses. Summary of the thesis. Faculty of Engineering of the Porto University, Portugal, 2010.
[2]   | Arno Daehnke, Strass Wave and Fracture Propagation in Rock. Thesis summery.
[3]   | S.C. IPROMIN S.A. Assessment Study on the Seismic Effect of Blasting Explosions on the Protected Sites and Methods used to mitigate this effect of explosions – control and monitoring procedures – Rosia Montana. Bucharest.
[4]   | M.W. Hildyard, A.M. Milev. Simulated rockburst experiment: Development of a numerical model for seismic wave propagation from the blast, and forward analysis. The Journal of The South African Institute of Mining and Metallurgy. 2001.
[5]   | Kuzmenko A. A., Vorobiev V.D., Denisuk I. I., Dauetas A.A.The seismic effects of the explosion in the rocks. Moscow, Nedra, 1990. 173 с.
[6]   | Medvedev S.V. Engineering seismology, Gosstroiizdat, Мoscow, 1962, 283с.
[7]   | Boiko V.V. (Elder) Seismic effect of explosions in industrial conditions of the block structure for Ukrainian granite. Collection of scientific papers. Theory and practice of improving blasting. Kiev. Naukova Dumka.-1990. С. 107-110.
[8]   | Sadovskiy M.A., Pisarenko V.F. Seismic process in block medium. Moscow, Nauka. 1991. 96 с.
[9]   | Safonov L.V., Kuznetsov G.V. The seismic effects of the explosion of blasthole charges. Moscow, Nedra, 1967.
[10]   | Kuzmenko А. А., Vorobev V. D., Denisyuk I. I., Dauetas А. А.. Seismik effects of blasting in rock. Oxford IBH Pyblishing Co. Pvt. Ltg, 1993. 169 p.
[11]   | Padukov V.A. Mining Geomechanics: Textbook. Collection of scientific papers of Sent-Petersburg’s Mining, 1997. 134с.А. с.
[12]   | Kucheryaviy F.I., Efremov E.I., Kucheryaviy U.F., Myadenets B.N. The method of explosive destruction of rocks. State Committee. USSR for Inventions and Discoveries 2476203, 1979.
[13]   | Boiko V.V. Seismic safety problems for blasting work in Ukrainian opencast mines, Monograph. Vudavnutstvo Stal, Kyiv, 2012.
[14]   | Bazhenov V.G., Kochetkov A.V., Krilov S.V., Feldgun V.R. The numerical solution of two-dimensional non-stationary problems of interaction of thin-walled structures of soils. Applied problems of strength and ductility. Union Interuniversity collection. Mining University – 1984. – С. 52-59.
[15]   | Кочетков А.В, Фельдгун В.Р., Цветков А.Ф. Numerical simulation of the explosion in a cylindrical shell filled with liquid. Applied problems of strength and ductility. Union Interuniversity collection. Mining University – 1991. p. 76-85.
[16]   | Remez N.S. Features deformation of multicomponent solid viscoplastic medium with variable viscosity under dynamic loads. Herald of the National Technical University of Ukraine «Kyiv Polytechnic Institute». Series of «Mining», #3, Kiev 2000. С. 34-39.
[17]   | Boiko V.V., Remez N.S., Hlevnuk T.V., Shevchenko U.V. The dynamic behavior of a layered cylindrical shell in a ground massif under explosive loading. Herald of Acoustics. Kiev. 2003. – № 2. С.10-16.
[18]   | Risto Dambov, Vojo Mircovski. Characteristics of rocky massif in aspect of intensity from seismic waves associated with blasting. Proceedings of the VI International Geomechanics Conference 24-28 June 2014, Varna, Bulgaria
[19]   | Brekhovskikh L.M., Godin O.A. The acoustics of inhomogeneous media. Volume 1. Fundamentals of the theory of reflection and propagation of sound. Moscow. Nauka, 2007.
[20]   | Saenger E.H., Shapiro S.A. Effective velocities in fractured media: a numerical study using the rotated staggered finite-difference grid. European Association of Geoscientists & Engineers. Geophysical Prospecting, 2002, 50, 183-194.
[21]   | Tod S. R. The effects on seismic waves of interconnected nearly aligned cracks. Geophys. J. Int. (2001) 146, 249-263.
[22]   | Boiko V.V. (Elder), Boiko V.V. Industrial Seismic Safety Requirements for Buildings and Constructions. Collection of scientific papers. Research Institute of Earthquake Engineering. Turkmenistan, Ashgabat, Ylym. 2014.