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HomeMy WebLinkAboutMeasurement & Analysis of Blast Induced Ground & Air Vibration D o D D D D D D I D '0 o D o D D o D D D .Measurement and Analysis of Blast Induced Ground and Air Vibration in the Vicinity of the Martin Marietta Aggregates, North Indianapolis Quarry Indianapolis, Indiana Prepared for: Martin Marietta Aggregates 1980 E. 1 t 6th Street, Suite 200 Carmel, Indiana 46032 Prepared by: Vibra- Tech Engineers, Inc. 109 East First Street Hazleton, Pennsylvania 18201-0577 1-800-233-618 t November 30,2005 o o D D D D o o D D o D o D D D D o o TABLE OF CONTENTS EX E CUTIVE SUMM.....:\. R Y .......... ........ ........................... .............. ................................-.... ..........1 IN T RO D U CTI 0 N ......................... ............ ............................. .............................. ................... .... ...2 STUn Y TO PIC....................... ............................ ................_...................................-....................3 ESTABLISHED GROUND VIBRATION CRITERIA AND RELEVANT RESEARCH......5 RECOMMENDED GROUND VIBRATION CRITERIA FROM USBM RI-8507......... ..................................5 RESEARCH ON REPEATED VIHRATIONS FROM RI-8896 ......................................................... ............7 STRUCTURAL RESPONSE TO VIBRA TrONS.... ............................................ ........... ........ .......................8 TIlE RSVP TECHNIQUE......... .......... .......... ...... ............ .......... .............................. ...... .............. ........ II RECOMMENDED AIR VIBRATION CRITERIA FROM USBM RI-8485.................................................13 ISOS EIS.l\'11 C SURVEY ....._........ ...............................................................................................14 ISOSEISMIC TECHNIQUE..... ... .................................................... ............................ ..... ..................... 14 DATA ACQUISITION PROCEDURE .... ...... .... ............ .... ...... ...... ......................... ... ........ .......... ............15 How TO READ THE ISOSEISMlC MAPS ............................ ................................ ................................16 DISCUSSION OF ISOSEISMIC MAPS.................... .......... .............. .............................................. ........ 17 VI BRA TION AN A LYSES ..........................................................................................................18 COMPARISON 01"' GROUND VIBRATION ToUSBM CRITERIA...........................................................18 COMPARISON OF AIR OVERPRESSURE ro USBM CRlTERIA............................................................18 SUMi\'fARY OF VlBRA nON ANALYSTS .............................................................................. t 9 R.EFE.R E N CES............... ___."........................ ................. .............................................................20 A P P'END IX A ...................._........ "._.................._...... ......................................... .... ....................2 ] o Q o o o D o o o D o o o D o o o o o LIST OF FIGURES FiGURE 1. ROCK BREAKAGE BY ExPLOSIVES .................................__...........................................................3 FIGURE 2. US BUREAU OF MINES RECOMMENDED VmRATJON CRITERIA (FROM RI-8507)..........__........... 7 FIGURE 3. RESPONSE FOR A TYPICAL 2-STORY STRtlCTIJRE ..............__....................................................... 9 FIGURE 4. DETERMINATION 01' STRUCTURE'S NATURAL FREQUENCY BASED ON STRUCTURE HEIGHT... 11 FIGURE 5. FUNDAMENTAL FREQUENCIES OF RESIDENTIAl. STRlJCTlJRES................................................. 12 2 o o D D o D o D D D o D o o D o D o o LIST OF TABLES TABLE 1. SAFE MAXIMUM NRl3LAST LEVELS (USBM Rl-8485). .__............................................--14 3 o o o o o D o o D D o D o o o o D D o Executive Summary A vibration study that measured and analyzed ground vibrations and air overpressures from blasting at the Martin Marietta Aggregates' North Indianapolis Quarry was conducted on May 20,2005. The purpose of this study was to determine if the blast induced ground vibrations and air overpressure levels were in compliance with the established u.s. Bureau of Mines criteria. On May 20, 2005, 151 digital seismographs were deployed to record the ground vibrations and air overpressure levels produced by the detonation of four separate blasts. The blasts consisted of one single hole blast, Signature Blast I (Northeast Wall, Bench Level A); one multiple-hole production blast on the surface, Production Blast 1 (Northeast Wall, Bench Level A); and two heading blasts underground, Production Blast 2 (N2 north of GG) and Production Blast 3 (Z west ofN24). The seismographs were located in areas surrounding the quarry. The results of the study show that all of the ground vibrations recorded on May 20, 2005 in the vicinity of residential and commercial structures surrounding the North Indianapolis quarry were in compliance with the USBM recommended limit. The recorded air overpressures outside the permitted quarry area were also in compliance with the USBM recommended limit. The calculated structural response for residential structures was compared to the research of Dr. Meadearis regarding blast vibration damage potential of the blast induced vibrations. This comparison showed that the non-damage probability at all structures, for each of the blasts, was 100 percent. o D D o D o D o o o D o o o o o o D o Measurement and Analysis of Blast Induced Ground Vibration and Air Overpressure in the Vicinity of the Martin Marietta Aggregates, North Indianapolis Quarry Indianapolis, Indiana Introduction This is a report of the Vi bra- Tech Engineers, Inc. vibration study which measured and analyzed ground vibrations and air overpressures from blasting at the Martin Marietta Aggregates North Indianapolis Quarry. The study was authorized by Mr. Dan Hoskins of Martin Marietta Aggregates. The fieldwork was completed on May 20,2005. The purpose of this study was to determine if the ground vibration and air overpressure levels were in compliance with the U.S. Bureau of Mines vibration criteria. The vibrations produced by the detonation of four separate blasts were monitored by 151 digital seismographs on May 20, 2005. The blasts consisted of one single hole blast, Signature Blast I (Northeast Wall, Bench Level A): one multiple-hole production blast on the surface, Production Blast I (Northeast Wall, Bench Level A): and two heading blasts underground, Production Blast 2 (N2 north of 00) and Production Blast 3 (Z west of N24). The seismographs were concentrated in the residential and commercial areas surrounding the quarry. This large array of seismographs permitted IsoSeismic contour maps to be made showing the distribution of blasting vibrations around the quarry. The IsoSeismic maps indicate the intensity of the vibrations from each blast, measured in peak particle velocity. 2 o o o o o o o D o o o D o D o o o o o Study Topic Human perception and response to ground vibrations from blasting have been a continual issue for the mining industry, the public living near mining operations, and regulatory agencies responsible for setting environmental standards since the 19305. [0 order to understand the nature of this issue the following pages are dedicated to educating the reader about mineraI recovery via blasting, the effects of blasting operations on the earth, the causes of blast vibrations, why people feel vibrations, and how vibrarions are measured. ~ Free Face Explosive detonates. Detonation pressure crushes surrounding rock, creates fractures. Explosion pre ure expands cracks. Movement beg ns toward free face. Pressure is released, cracking stops. Figure J. Rock Breakage by Explosives A common misconception among the general public is that mine and quarry operations blast so that they can crush stone. Crushed stone is actually produced in machines called crushers. In order to obtain rock for the crushers, a small amount of bedrock must be broken off and fractured into pieces which will fit into the crusher. The most cost-effective way to achieve this is through blasting. A typical response from homeowners located near blasting operations is that since they feel the vibrations at a great distance, the fracturing of rock must also occur at this distance. This assumption is far from the truth. When a blast hole is detonated, the explosion produces a high temperature, high-pressure gas. This gas pressure, known as the detonation pressure, crushes the rock adjacent to the borehole. The detonation pressure rapidly dissipates, consuming approximately ten to fifteen percent of the energy available in the explosive. The remaining energy produces a second, lower pressure gas, known as the explosion pressure, Most of the work done by the explosive is done by the explosion pressure. The explosion pressure expands the cracks made by the detonation pressure, and pushes the fractured rock toward the free face. Once the blasted material is separated from the bedrock, the gas pressure escapes, and no further fracturing of the bedrock can occur, The momentum of the fractured rock continues its movement toward the open pit. This entire process occurs within a few hundredths of a second after the detonation, and takes place within about tw'enty feet of a typical quarry blast hole. 3 o o o o D D D D D o D o o D o D o D o The vibrations that homeowners feel are not caused by the fracturing of rock. Blast induced ground vibrations are primarily the result of the delonalion pressure aCling on lhe rock around the borehole and the explosion gas pressure pushing the fractured rock away from the bedrock toward the open pit. The application of this large force against the bedrock followed by its subsequent release causes the bedrock to vibrate, much like pushing and releasing a swing will cause it to vibrate. When a part of the bedrock is vibrated within the quarry, the vibration is transmitted into the ground surrounding it. This transmission of vibration is called propagation. The propagation of the ground vibration continues away from the blast location in all directions, similar to ripples in a pond which move away from the initial disturbance. The ripples in the pond, like ground vibration, are examples of elastic vibration. Elastic vibration means that the material never moves very far from its original position while it is vibrating, and once the vibration event is over, the material will be in its original position and condition. Unlike the ripples in the pond, the motion of the ground is so small it cannot be detected visually. Therefore, sensitive scientific equipment is required for its measurement. Outside of a quarry, the ground rarely moves farther than the thickness of a sheet of paper before returning to its original position, and it may do so faster than the eye can sense. Seismographs can measure how the ground moves from its original position, much like a tishennan's bobber can detect how the water surface moves from rest when a ripple passes by. As the ground vibrations propagate further away from the source, the energy is dissipated. When the energy dissipates, ground vibration amplitude decreases, until eventually the ground vibration falls below perceptible levels. The rate at which ground vibration amplitude decreases as it propagates away from the blast location is called seismic attenuation. Seismic attenuation has been studied extensively and found to occur geometrically. A geometric reduction in ground vibration means that ground vibration amplitude decreases very quickly near the source, but very slowly far from the source. As a result, almost all of the ground vibration energy is dissipated within the quarry, but the small amount of energy remaining may produce perceptible vibrations at great distances. Since blasting produces perceptible ground vibrations beyond the quarry property, attempts to control vibrations have been accomplished via laws, regulations, and industry standards. Maximum pennissible levels have been established based on academic and government studies of the effects of vibration on nearby property and people. Seismographs are used to measure the vibrations, and ensure that the permissible levels are not exceeded. The seismograph may measure how far the ground moves from rest (displacement), how fast it moves (velocity), or how fast the velocity changes (acceleration). These three parameters are related by the frequency of the vibrations. Frequency is a measure of how many times the ground will vibrate through its original position in one second. The seismograph also measures frequency, which is commonly reported in cycles per second or hertz (Hz). Standards limit the maximum amount of vibration that can occur at any point, or particle, on the ground surface. The limit is therefore commonly referred to as a peak particle displacement, peak particle velocity, or peak particle acceleration. Nearly all residential vibration standards limit the peak particle velocity. 4 o o o o D o o D ID I D o D D o o o o o o Operator!; must have a method of estimating ground vibrations from a blast during its planning to confidently adhere to vibration limits. Since the amplitude of ground vibration is determined by how much energy is present to create vibration and how far the vibrations have propagated, researchers devised a single number to relate these parameters. This number, called the Square Root Scaled Distance, or simply Scaled Distance, relates ground vibration amplitude to explosive charge weight and distance from the blast. The scaled distance requires the explosive charge weight to decrease as the distance from the blast decreases in order to adhere to ground vibration peak particle velocity limits. The scaled distance provides a convenient method of comparing the ground vibration potential of different blast designs. Some regulations do not require the use of seismographs if the scaled distance from the blast is large enough. In response to quarry operator desires to minimize ground vibrations and still operate efficiently, explosive manufacturers developed millisecond delayed blasting caps. Research has shown that several charges detonated only a few thousandths of a second apart would not only produce less ground vibration, but are also more effective at fracturing and moving rock than a simultaneous detonation of all charges. All quarry blasts today consi st of many small charges detonated several hundredths or thousandths of a second apart., and the scaled distance has been defined as the total weight of explosives detonated within a certain period of time, rather than the total weight of explosives in the blast. Air-borne vibration may also be produced by blasting. These vibrations may occur within the audible range of the human ear (sound), or at frequencies below those humans can hear (infrasonic). Many sources for air vibration exist in a typical blast, but all can be traced back to either the venting of the detonation and explosion pressures or the fractured rock pushing air out of the quarry. Seismographs are equipped with microphones and measure these changes in air pressure occurring as the air vibration passes to determine if permissible limits are exceeded. Established Ground Vibration Criteria and Relevant Research Recommended Ground Vibration Criteria from USBM RI-8567 The USBM has studied various aspects of ground vibration and air blast since 1930. In 1971, the culmination of over forty years of research was compiled into Bulletin 656 entitled '"Blasting Vibrations and Their Effects on Structures". In this publication the author reviewed effects of blast design on the generation of ground vibrations and air blast propagation. Bulletin 656 developed three fundamental parameters that are used today in the field of blasting and vibration seismology. First, peak particle velocity should be used as a measure of ground vibration. Second, a minimum time delay interval of eight milliseconds (ms) between explosive charges should be used to calculate scaled distance. Third, a safe scaled distance of 50 ftllbl: for quarry blasting should be implemented in the absence of vibration monitoring. Bulletin 656 also collected additional data that further substantiated the limit of 2.0 in/see peak particle velocity as the overall safe level for residential structures. These recommendations were widely adopted by the mining and quarrying industry and incorporated into numerous state and local ordinances that regulate blasting activity. Subsequent research conducted by the USBM from 1974 through 1980 reanalyzed the blast damage problem and expanded on previous studies. USBM Report of investigation Rl-8507, 5 D o o o D D D D D D o o D o o o o o o entitled "Structure Response and Damage Produced by Ground Vibrations From Surface Mine Blasting" examined the more serious shortcomings of previous etTorts. In this study, direct measuremenls of slmclural response and damage fi'01n aclual surface-mine produclion blasling were observed in 76 residences for 219 production blasts. This data along with damage data from six additional studies were combined with the historical data from Bulletin 656. Particular emphasis was placed on the importance of frequency to structure response and its relationship to damage. The fonowing significant facts were concluded in RT-8507: · Particle velocity is still the best single descriptor of ground motion. · All homes eventually crack because of a variety of environmental stresses. These include changes in humidity and temperature, settlement from consolidation and variations in ground moisture, wind load, and even water absorption from tree roots. · Damage potentials for low frequency blasts, below 40 Hz, are considerably higher than those for high frequency blasts, above 40 Hz. In other words, the probability of damage for a blast with an amplitude of 2.0 in/see at 10 Hz is greater than for a blast with an amplitude of 2.0 in/see at 50 Hz. · Home construction is a factor in the minimum expected damage levels. Gypsum-board (Drywall) interior walls are more damage resistant than older, plaster on wood lath construction. · The practical and safe criteria for blasts within the range of the natural frequency of residential structures are 0.75 in/see for modem gypsum-board interiors and 0.50 in/see for plaster on lath interiors. For frequencies above 40 Hz. a safe particle velocity maximum of 20 in/see is recommended for all houses. · Threshold damage is classified as minor cosmetic damage such as loosening of paint, small plaster cracks at joints between construction elements, and lengthening of old cracks. Such damage is similar to that caused by a variety of environmental stresses including humidity and temperature changes. The chance of threshold damage from a blast with peak particle velocities of 0.50 in/see is extremely small and decreases almost asymptotically below 0.50 in/sec. Therefore, if the levels of ground vibration are below the recommended limits established by the USBM the potential for damage is essentially zero. 6 D D The culmination of this study was the Appendix B curve which \vas entitled '"Altemalive Blasting Level Criteria". The Appendix B curve to the left used both measured structure amplification and damage evaluations to develop a criteria that involved both displacement and velocity. The curve in Figure :2 5hO\\'/5 that above 40 Hz_ a constant peak particle velocity of 2.0 inisec is the maximum safe value. Below 40 Hz however, the maximum velocity decreases at a rate equivalent to a constant peak displacement of eight mil (0.008 inch). At frequencies corresponding to 0.75 in/sec for DI)'wall, and 050 in/see for plaster, constant particle velocities are again appropriate. An ultimate maximum displacement of 30 mil is recommended when frequencies below 4 Hz are encountered. Using this scheme, the Bureau was able to recognize the displacement-bound requirement for house responses to blast vibrations, and provide a smooth transition for intermediate frequency cases. U.S. BUREAU OF MINES CRITERIA From Rt'porl RI-8:'i1l7 (No'.cmhcr, 1(811) 10 o <J C) <II :E 2.0 ini,!,..ec. D ~ ;.:- l- e:; o u:j 1 > L1J ..J U i= 0:: <l: 11. (}.7~ itV$(lt': 01 W.lII 0.50 in.'~c ., __...__P1jsje!__' D 0.1 10 100 ~ FREQUENCY (Hz) ~ Figure 2. US Bureau of !\llines Recommended Vibration Critel"i:l (From RI-8507) D D Research on Repeated Vibnltions from RI-8896 ~ Homeowner reaction to the research used to develop the Appendix B curve in RI-8507 is typically met with skepticism Residents often counter with the fact that their homes are repeatedly being subjected to vibration loads and that there must be a cumulative effect on the structure. In 1984, the USB:\'1 published RI-8896 entitled, "Effects of Repeated Blasting on a Wood Frame House". This study \vas the first to document long term strain response ofa house. Strain is an engineering measure of deformation llsed to predict failure. A strain of t mil/in indicates that on average, every inch of a material was stretched or compressed one thousandth of an inch. For example, the length of an eight-foot long section of wallboard would change by approximately == 0.1 in. Long-term strain measurements alkmied blast-induced strains to be compared with those produced by changes in environmental factors such as temperature, humidity, and human activity. D D D Q During this study the Bureau arranged to have a wood-frame test house built in the path of an advancing surface coal mine so that the etfects of repeated blasting on a residential house could be studied. In a two-year test period, 587 production blasts were tired \vith peak particle velocities ranging from 0.10 in/sec to 6.94 in/sec. Later the entire house was shaken mechanically to produce fatigue cracking in \Nalls. The tirst crack appeared in a dryv\'all tape joint after the equi valent of 56,000 cycles. This is the equivalent of 28 years of shaking by blast- generated ground motions orO.50 in/see tvy.ice a day_ ~ D o 7 D o o o D D D D D D o o D o o D o D o o The following significant facts were concluded from this study. Conclusions in RI-8896 indicate that threshold type cracks appeared in the test house with and without blasting. Because of this, the researchers felt that observations of individual cracks were not the best indicator of the effects of blasting. The better indicator would be observations of the rate of threshold crack occurrences. In this study, the rate of threshold cracking when ground motions were less than 0.50 in/sec was not significantly different than when motions were between 0.50 and 1.0 in/sec. However, when ground motions exceeded 1.0 in/see, the rate of crack formation was more than three times the rate observed when vibrations were less than 1.0 in/sec. Construction materials can fail by fatigue. However, for most materials the stresses must be a significant fraction of the ultimate strength of the material in order for this to occur. Siskind states that in general it must be at least 50%. He further states that load levels well below failure strength will not produce failure no matter how long they are applied. In terms of the ground vibration criteria developed in Rl-8507, if ground vibrations are kept below the safe-level no fatigue could be expected for construction materials. Structural Response to Vibrations The potential for damage to a structure from blast vibrations is also obviously dependent upon how that structure vibrates. Given the importance of how ground vibrations induce house vibrations, or structural response, the following section of this report shall provide a foundation to understand how ground vibrations can affect residential structures, and how engineers can predict these effects. Residential structures are complex structures. The many components of a residential structure mean that at almost any vibration frequency, some element of a structure will respond. This is why the vibrations produced by walking in a room may cause the dishes in a cupboard to rattle but not the pictures on the opposite wall. Vibrations generated by walking through a room are normally not considered damaging to the structure by the occupants. The vibration is familiar to them, and only a small component of the entire structure is vibrcuing. Homeowners are confident that the structure was designed to safely withstand the vibrations produced by everyday human activity. Similarly, structures are designed to safely withstand events that cause the whole structure to vibrate such as wind force and elastic ground vibration. When ground vibrations emanating from a blast encounter a structure, that structure will begin to vibrate as welL The characteristics of the structure and its interaction with the ground vibrations determine how the structure will respond to these vibrations. The frequency, amplitude, and duration of the structure's vibration are dependent upon not only the ground vibration but also the structure's properties. The most important properties of a structure in determining how it wi1l vibrate are its mass, stiffness, and damping. Damping is a measure of a building's tendency to return to rest once set into motion. The mass and stiffness of the structure detennine the fundamental frequency at which it will vibrate freely. The relationship between the fundamental frequency of a structure and the frequency of ground vibrations is most important in determining a structure's response. 8 When an entire structure vibrates as a unit, it shakes at some fundamental oscillation frequency. When the structure is excited by a blast induced ground vibration, it must move at the same liequellcy as the ground. If the frequency of the ground vibrations match the fundamental frequency of the stmcture, the structure may magnify these vibrations. Engineers can determine how much the vI/hole structure will vibrate from the ground vibrations by calculating [he response of the house as a damped single-degree-of-freedom s)'stem. A single-degree-of- freedom system means that the house will vibrate in the direction of the ground vibration, such as vertically from vertical ground vibrations or laterally from lateral ground vibrations. A damped system will return to rest on its own at some time after it is excited; it \vill not vibrate indefinitely once the ground v'ibration stops. The solid line in Figure 3 below shmvs the solution to an underdamped single-degree-of-freedom response for a typical 2-story stmcture vibrated from its base. The relative vibration amplitude is determined by the structure's damping ratio. The fundamental frequency of this stmcture was assumed to be 6.9 Hz, typical for a 2 story residential structure as per the research of Dr. Kenneth Medearis. Further explanation of Dr. Medearis' research will be discussed later in the report"s section regarding the RSVP technique. Clearly ground vibrations \vith frequencies above 9 Hz \-vill have less drect on this type of structure than those with frequencies below' 9 Hz. Under'damped Single-Degr-ee-of-Fn~edom NOI"malized Response Spectrum for a Typical 2 Story Residential Stl1lctul'e Figure 3, Response for a Typical 2-Stol')' Structure The structure response illustrated in Figure 3 was calculated for steady state vibrations. Transient vibrations mayor may not evoke a response equal in amplitude to the solid line_ The duration of the transient vibrations, as \.-vell as the frequency, vvill determine the amplitude of the structure's vibration. If the duration is long enough, the maximum stmctural response will occur. Shorter duration ground vibrations will produce a smaller response. occurring somew'here within the area under the curve of the graph. D D D a ~ D ~ ~ ~ ell "'C :J ~ a. E <t c o ~ m ... .c > "'C ell .~ III E ... o z D D ~ ~ D D D i ~ , ! "Ground Vibr~tion , ~----~----r----r----r----r---- ~ ; ~ i Structure R~spons, 5 10 15 20 25 Frequency 30 35 40 The amplitude of the stmcture's vibration alone is not enough to determine the potential for damage to the structure. Because the structure begins at rest, its motion always lags behind the motion of the ground. This lag is referred to as a phase shift in the vibration episode. The phase shift from ground vibration to stmcture response is determined by how closely the frequency of the ground vibrations matches the fundamental frequency of the stmctllre. The difTerence in the o D o 9 o o D D D D D D o o D D D o D D o D o phase of the ground vibrations with respect to the structure means that each may be moving in opposite directions at some point in time. When this occurs, the stresses in the structure and the potenlial for damage are altheir greatesL The strain induced in the structure by the phase shift determines the potential for damage. Equivalent amplitudes of structural response can result in different levels of strain, depending on the frequency of the vibration. For this reason, human perception and vibration recordings limited to structure interiors are not valid indicators of the potential for damage by a ground vibration episode. 10 Q o ~ ~ D ~ o o ~ ~ D ~ o ~ ~ D ~ ~ a The RSVP Technique The Response Spectrum Velocity Prolile (RSVP) technique used in this study was developed by Dr. Kenneth .Medearis [t is a p(J\,verful vibration analysis too] which not only confonns to USBf\', and Office of Surtace Mining Reclamation and Enforcement (OSMRE) recommendations, but also provides insight into the responses of valious types of structures to a given vibration episode. Research by the USBl\.r and OS7vfRE has determined that the natural frequency of typical residential structures ranges bet\veen 3 and 16 Hz. Within this range, blast vibration limits recommended by the LSBM and OS\iIRE are most stringent. Field measurements by :vledearis shov..ed the natural frequency of residential structures as being primarily determined by the structure's height. Figure 4 graphically depicts this relationship between structure height and natural frequency. Nledearis related the probability of blast vibration damage with the stmcture's response, Rather than using only ground vibration levels, he developed a rational damage criteria based upon structural response. He published a damage criteria based upon the relative velocity of the ground motion to a residential structure's response motion. This calculated level of relative velocity, termed Pseudo Spectral Relative Velocity (PSRV), became the basis for Medearis' damage threshold limits. Approximate Natural Frequency of Low-Rise Residential Structures 15 " " , '. '. " '. " " ..."..... ". " . '" . ",-.,., '...... ..., " , " ". "'. " - N - "- Q) :I: - ". "" '-. '-.. '-. " " 10 . ''''. ". '. ". '. . .... -", ''''. '" ". '. "".., ". " ''llo., ~ U C 0,) ::J c- O,) "- LL " 5 , '. , ", Dashed lines represent one standard deviation from the mean. 10 15 20 25 30 35 Residence Height. Ground to Peak (feet) Figure 4. Determination of Structure's Natural Frequency Based on Structure Height ] I In hi s research Medearis measured the damping ratios of sixty-three residential stnIctures. He concluded that a residential stmcture's damping is not related to its age, dimensions, natural frequency, or geographical location The damping for all residential structures ~vas found to fall withi n a very narrow range. In later work ]\:ledearis showed that his methods for determining stnIctural dampi ng, natural frequency, and response compared quite favorably with the measured structural response. D I~ ~ ~ ~ ~ D ~ ~ D o D o D ~ ~ ~ o o (a) One Story Structure 0.25 0.2 0.15 0.1 0.05 (b) . One & One Half N J: 0.25 Story Stnlcture - ~ 0.2 ... >. 0.15 ..... (/) 0.1 c: 0.05 (1) C (c) ~ Two Story Structure ... - 0.25 .- ..Q ('Q 0.2 .c 0.15 0 '- 0.1 0- 0.05 (d) All StructUl-es 0.25 0.2 0.15 .~ 0.1 0_05 0 5 10 15 20 Figlll'e 5. Fundamental FI'equencies of Residential Structures ..~;-'. . t~'l,~, '~""-Jl- A ~.~ L ", \.,~'..: .' ,,;,-~."', -." ,,:~t ': ....."'._ 11 IJ · ii"';' .~ '0"H . fjii":~~,~:{",: ". - . , 12 ..... Peak relative velocity for a stnlcture is determined by the ground vi brations, the structures damping ratio, and the fundamental frequency of the stnlcture. The probability that a given structure type \vil! have a gi ven natural frequency \vas empirically determined by Medearis as shown in Figure 5 to the left Medearis' method is a more rational approach to evaluating the risk to residential stmctures as a result of blast induced ground vibration. These techniques developed by Dr. Medearis are used by Vibra- Tech to analyze blast vibrations. Vibra- Tech calls the method by the more familiar acronym RSVP. When blast vibrations at a residential structure conform with the USB\1 recommendations, the probability of damage is essentially zero. \Vhen blast vibrations exceed USBiVl recommendations Vibra- Tech uses the RSVP analysis to calculate the probability of damage based on Medearis' work. D o D D D D D o D o o D o o o o o o o Recommended Air Vibration Criteria from LJSBM RI-8485 The USBM has also sel forlh recommended airblasllimils in ilS Report ofInvesligalion Rl-8485, "Structure Response and Damage Produced by Airblast From Surface Mining". Although the air vibrations produced by production blasting are typically referred to as noise levels, the USBM report recognize that airolasts with frequencies below the threshold of human hearing (infrasonic) are capable of producing structural response. The most common example of infrasonic air vibrations that may produce structural response is wind rattling a window. Accordingly, the USBM has recommended limits based upon the frequency range of the recording system. The maximum allowable air-blast limits increase as the range of the recording system expands further below the audible frequency range of the human ear. The weight of the air in Earth's atmosphere produces pressure upon everything on Earth. This pressure, known as atmospheric pressure, is commonly reported in daily weather reports in millibars (mbar, metric) or inches of mercury (in.Hg., USCS). The air vibrations produced by blasting cause the normal air pressure to fluctuate. Changes in normal air pressure due to the airblast are referred to as overpressure, as in pressure over atmospheric pressure. Air overpressure resulting from blasting is measured by microphones attached to seismographs. When air pressure changes rapidly however, different pressures can result on both the inside and outside of a structure. A change in pressure that occurs between locations is often called a pressure gradient. A pressure gradient from the inside of a structure to the outside produces forces which are exerted over the structure's exterior surfaces. These forces, if large enough, can cause structural damage. Examples of causes of air pressure gradients which damage residential structures are the winds from hurricanes, tornadoes, and thunderstorms. Changes in air pressure due to blasting, like wind, occur very rapidly, resulting in different pressures on the inside and outside ofa structure. These changes in pressure are not stationary, they travel away from their source. When either a blast induced air pressure wave or a gust of wind propagates, they can produce a pressure gradient not only from the inside of a structure to the outside, but also from one side to the other. The difference between air pressure waves from blasting and those produced by wind lies in the magnitude and frequency. Changes in air pressure due to wind are many times greater than the changes in pressure produced by blasting. This is why a gust of wind may push a garbage can down the street., but the airblast from a quarry cannot. The frequency of the changes in air pressure produced by wind is much lower than the frequency of the air pressure wave produced by blasting. Two imponant etl'ects can be traced to this difference in frequency. First, wind remains inaudible, while air overpressure from blasting may rumble or boom. Second, higher frequency changes in air pressure due to blasting mean that forces on the structure's exterior change quickly. A window pane may be alternately pushed and pulled fast enough to make it rattle as a result of a quarry or mine blast. Wind force, on the other hand, does not change direction quickly. Wind can therefore push or pull on a window pane with a much greater force without producing audible sounds. Most air overpressures from blasting are measured in thousandths or ten thousandths of psi. Rather than reporting air overpressures in psi, most regulations specify decibels (dB). Since a decibel is a measure of change, it must be with respect to some value. The reference pressure for air overpressure monitoring is 2.9 x 10-9 psi. A small change in decibels can represent a very 13 o o D D D D D D D o o D D o o o o o D large change in pressure. Doubling of the overpressure in psi yields a 6 dB increase; a tenfold increase in overpressure equates to a 20 dB increase. Mines and quarries generally limit themselves to less than 130 dB, or aboul one one-hundredth of one pound per square inch (0.01 psi). Structural damage as a result of air overpressure is generally conceded to not be possible without extensive window breakage, as the glass is the weakest portion of a structure's exterior where this pressure acts. Window panes are designed to safely withstand changes of 1.0 psi (180 dB) when ,properly installed, and even in the worst situation a pane should be able to withstand 0.1 Ibs/in- (150 dB). Air overpressures from mine and quarry blasting rarely exceed 0.01 psi. (130 dB), about one one-hundredth of the overpressure that a window can safely withstand. The safe air-blast limits recommended by the USBM were determined by analyzing structural response and damage from many applicable studies. Based on a minimal probability of the most superficial type of damage in residential-type structures, any of the following represent safe maximum airblast levels. Table 1. Safe Maximum Airblast Levels (USBM R1-8485). '.ower Frequency Limits a/Measuring .'))'stem Atfaximunl Level ill dB O. I Hz high-pass system 134 dB 2 Hz high-pass system 133 dB 5 or 6 Hz high-pass system 129 dB c- slow (events not exceeding 2 sec duration) 105 dB The recommended limits listed in Table I were compared to a composite of five impulsive noise studies for human tolerance in the USBM report. Based upon these studies, the USBM concluded that these recommended airblast limits would provide an annoyance acceptability to 95 percent of the population for one to two events per day. The USBM also concluded that the single best airblast descriptor is the 2 Hz system. These recommendations have been accepted by many states. The GeoSonics MicroSeis, and the SSU- 2000DK Seismof,rraphs used in this study all operate with a low frequency limit of 2 Hz in the air vibration measuring system. The maximum safe airblast level set forth by USBM RI-8485 for this type of system is 133 dB (re. 2.9 x 10"9 psi). IsoSeismic Survey IsoSeismic Technique The IsoSeismic technique is a powerful tool which empirically demonstrates the effect of geology on blast induced f,Jfound vibration. Just as residential structures may magnify certain types of ground vibrations, local surface geology can also respond to certain types of vibration. While the response characteristics of residential structures have been carefuJly measured and studied. the response of the geologic subsurface is not so easily quantified. The single-degree- of-freedom model of a residential structure has been shown to very closely approximate the motion of that structure, but such a model may be inadequate to predict the motion of the ground at allloeations around a quarry or mine. 14 o D D D D o D D D o o D D o D D o o o The IsoSeismic technique makes possible the simultaneous measurements of vibrations at many locations. The complex interaction of the vibrations as they propagate through the. geology around a quarry or mine determines the resulting ground vibration at each location. Simultaneous measurements of individual blast events at many locations reveal the result of this interaction. This interaction, or geologic response, is dependent on the geology at many locations around a quarry or mine, but is usually dominated by surface geology at the location of concern. Since the geology and its interactions will remain unchanged, the vibration characteristics for the area around the operation may be mapped. The geologic vibration response may increase the magnitude of the ground motion, change the frequency of the vibration, and increase the duration of the ground vibration. This type of response usually occurs in the shallow surface, where resonant frequencies are similar to those of residential structures. Since structural response is directly proportional to the magnitude of the ground vibration, to the duration of the vibration, and to how closely the frequency of the vibration matches the natural frequency of the structure, IsoSeismic contour maps immediately identify areas where structural response may be greater and the likelihood for complaints will be enhanced. By comparing the IsoSeismic contours produced by production blasting with those produced by a single charge blast, the IsoSeismic Technique clearly identifies areas of potential complaints and provides insight on site specific vibration response. The IsoSeismic survey is much more than just a map of relative ground vibration amplitudes around a quarry or mine. Each vibration event is collected as digital data by the IsoSeismic system which then computes the frequency, duration, and predicted structural response. The IsoSeismic system is capable of recording more than 1500 blast induced ground and air vibration events in less than one hour For a typical mine or quarry blasting two to three times per week, this amounts to more than 10 years of blast vibration recordings. More importantly, an immediate correlation between the vibration events can be made, since they are the result of the same blasts. Computer modeling of the data can 'reveal causes of complaints and potential solutions. Data Acquisition Procedure On May 19, 2005 representatives from Vi bra-Tech Engineers, Inc. met with representatives of Martin Marietta Aggregates and Orica to discuss and organize the collection of data at the North Indianapolis Quarry. On May 20, 2005 a total of 151 tri-axial seismometers were deployed for the registration of otie single hole signature blast, one multiple-hole production blast on the surface, and two heading blasts underground. The seismometers were deployed by personnel from Vibra-Tech to assure proper placement and ground coupling. The location of each seismometer and each blast is shovvn on the map in Figure A-I in Appendix A of this report. The density of the seismograph positions and the type of seismograph were determined by the density of residences and shot location. On the morning of May 20, 2005, all the seismometers to be used for the data collection were programmed to begin monitoring at 12:54 PM on that day. This precaution was necessary to ensure that the memory in the seismometer would not be filled with false events prior to the detonation of the blasts. The tirst blast was scheduled to be detonated at approximately I :00 PM followed by the three subsequent blasts over a period of approximately 15 minutes. Once all of 15 o o o D D o D o D o o D D o o o o o o the blasts were detonated the seismometers were collected and their data downloaded to computers for future analysis. During the detonation of Production Blast 3, none of the seismometers triggered indicating that the ground vibrations produced by that blast were below the trigger level of the seismometers. How to Read the IsoSeismic Maps An IsoSeismic map is a contour map of the measured ground vibrations produced by a blast. The contour lines on an IsoSeismic map connect locations of equal vibration, similar to contour lines on a topographic map which connect areas of equal elevation. The peak particle velocity level represented by each contour line is posted on that line. A separate map is created from the seismic data collected from each blast. It is not possible to collect seismic data at all locations around a quarry or mine, just as it is not possible for cartographers (map makers) to collect elevation data at all locations on a map Some of the data must be interpolated from trends observed in the field. However, two impollant facts about vibration can be used to aid in the interpolation. First, vibrations propagate away from the source like waves, therefore the amplitude cannot change abruptly. Second, ground vibration amplitudes attenuate geometrically when the geoloblJ' is uniform. Vibra- Tech has developed a unique method of incorporating both of these properties of ground vibration into a gridding technique that allows isoseismic contour lines to be drawn much more accurately. From these maps it will become apparent that the peak particle velocity at any particular location around the quarry will vary from blast to blast. There are numerous reasons why the peak particle velocity varies. A few of these reasons include the degree of confinement, fragmentation, and casting of the blasted material, the maximum charge weight per delay, the bulk strength of the explosive charge, the presence of water in the boreholes, and the direction of initiation of the blast. However, while the amplitude of the ground vibration at a particular site will vary from blast to blast, the rate at which the vibration amplitude changes will not. This means that jf the geology at a particular location tends to attenuate vibrations rapidly, it will do so consistently for either large or small vibrations. Similarly, if the geology tends to resonate, ampliry, or perpetuate the ground vibrations. it will do so for both large and small vibration levels. Because the rate at which vibrations are attenuated is constant for each individual location, the shape of the IsoSeismic contours can be used to identify trends in ground vibration. The vibration attenuation rates cause the peak particle velocity at a particular location to increase or decrease relative to its neighbors predictably. The location of these anomalous (deviating from what would be intuitively expected) vibration levels define the vibration "jingerprint" of a site. This means that regardless of the amplitude of the vibration source, cellain locations will have b'feater peak particle velocities than their neighbors. These locations will identify themselves by concentric circles of increased peak particle velocity on the IsoSeismic contour maps. These areas will reappear on many maps, often regardless of the blast location, number of holes, or peak particle velocity. These areas must be the focus of vibration control techniques. In order to identify the vibration fingerprint of a site, the following items should be kept in mind as one reads the IsoSeismic contour maps. 16 J o o . Contour lines denote locations of equal peak particle velocity, hence the name "isQseismic" lines or contours. Areas between contour lines will have a peak particle velocity between the values represented by the lines. The shape of the contour lines represents the site "fingerprint". o D D o D D D D o D o D D o o o o . The source of the vibration, the blast, will be located inside the circular contour line with the highest .value. The peak particle velocity will generally decrease as one moves away from the source. . The IsoSeismic contour lines, unlike elevation contours, do not necessarily represent a uniform change in amplitude. Ground vibrations attenuate geometrically, with the greatest change in amplitude occurring within the quarry or mine. In order to keep the IsoSeismic maps from becoming cluttered, higher amplitude isoseismic lines, especially those near the quarry, may represent a change of several tenths of an inch per second, while the lower amplitude lines farther away usually represent a change of one one-hundredth of an inch per second. Whenever possible, the lsoSeismic line spacing is consistent on each map included. . The distance between contour lines indicates how rapidly the vibration amplitude changes. Many contour lines spaced very closely together is an indication of a rapid change in peak particle velocity, usually downward. Contour lines spaced very far apart indicate that the peak particle velocity is changing very slowly. This is usually an indication of either a very small peak particle velocity or a possible low frequency geological response. . Contour lines that form small circles away from the vibration source are an indication of a geological response. The area inside the circle may be referred to as a vibration "hot spot" if the vibration amplitude is increasing, or as a vibration "dead zone" if the amplitude is decreasing. Contours around "dead zones" have small cross-hatches to identify them. . When isoseismic contour lines deviate from a uniform shape and spacing, some change in geology andlor topography exists. In this way, the isoseismic contour maps can often become an intuitive map of geology. Keep in mind that changes in geology usually introduce a change in frequency, as well as amplitude. lsoseismic contour anomalies necessitate a detailed analysis of the ground vibration signatures to determine the effect on structural response and human perceptibility. Abrupt changes in peak particle velocity, whether increasing or decreasing, can result in increased structural response and human perceptibility, resulting in increased complaints. Discussion of lsoSeismic Maps lsoSeismic maps for three blasts (Signature Blast I and Productions Blast I and 2) detonated in this study can be found in Appendix A of this report in Figures A-2 through A-4. The vibration tlngerprint for the area surrounding the North Indianapolis Quarry can be determined by examining all three IsoSeismic maps and noting the consistencies. A summary of the fingerprint, beginning to the north and proceeding clockwise about the map, is given below. 17 o o o o D o D D o o o o D o o o o D o . The result of the detonation of the one single hole and two production blasts on May 20, 2005 show that ground vibrations above 0.50 in/sec were not measured out side of the permitted quarry area. . A peak particle velocity 0.50 in/sec as observed on the maps for Signature Blast 1 and Production Blast 1 (surface shots) did not extend beyond 106th Street to the north, Hazel Dell Parkway to the east, 96th Street to the south, or Gray Road to the west. . The contour map for Production Blast 2 (underground shot) shows that the 0.50 in/sec peak particle velocity did not exceed the quarry property. . Figure A-5 in Appendix A shows the 0.50 in/sec projection for blasting at the northern most limits of Martin Marietta's Mueller Property South. This projection is based on IsoSeismic contours from Production Blast 1 migrated to this position. Based on the blast design currently utilized by Martin Marietta Aggregates, ground vibrations from blasting in the Mueller Property South are not expected to exceed USBM recommended criteria. Vibration Analyses Comparison of Ground Vibration to USBM Criteria The ground vibrations produced by Signature Blast 1 and Production Blasts 1 and 2, as recorded at 151 locations around the quarry on May 20, 2005, were in compliance with the criteria outlined in USBM RI-8507. Figure A-6 and A-7 of Appendix A graphically compares the ground vibration produced by the production and signature blasts to the Variable Particle Velocity versus Frequency Limits ofUSBM RI-8507 Appendix B curve. Figure A-6 shows a distribution of the frequencies-at-the-peak for the signature blast. Figure A-7 shows the data recorded for the production blasts. Production Blast 1 exhibits a strong cluster of data centered abound 20 Hz. For Production Blast 2 the majority of the data fell above 30 Hz. When compared to Figure A-6 this clustering of data shows the effects that the millisecond delays have in controlling the frequency character of the seismic signal. Comparison of Air Overpressure to USBM Criteria Air overpressure levels from the Production Blast 1 was not really similar to those of signature blast. This can be seen on Figure A-8 and A-9 in Appendix A. These figures show a comparison of the measured air overpressures to the criteria established by the USBM in RI- 8485. As evidenced by the graphs, resulting air overpressures are well below the established criteria for the production blast. 18 o o o o D D D D D o o o D o D o o o o Summary of Vibration Analysis . All ground vibrations recorded on May 20, 2005 were in compliance with the USBM recommended limits. The recorded air overpressures outside the permitted quarry area were also in compliance with the USBM recommended limits. . All of the vibrations recorded in the vicinity of residential and commercial structures surrounding the North Indianapolis Quany were in conformance to the most stringent USBM recommendations for residential stmctures. The calculated structural response for residential structures was compared to the research of Dr. Medearis regarding blast vibration damage potential; the 11011-damage probability at all structures, for each of the blasts, was 100 percent. . Ground vibrations did not exceed 0.29 in/see outside of property owned or leased by Martin Marietta Aggregates as a result of the production blasting on May 20, 2005. Ground vibrations of this magnitude and frequency do not constitute a hazard to residential structures. Air overpressure levels did not exceed 131 dB outside of property owned or leased by Martin Marietta Aggregates as a result of the production blasting on May 20, 2005. RespectfuJly Submitted, VIBRA-TECH ENGINEERS, INC ~--- Kristin E. Ferdinand Area Manager ~ Douglas Rudenko, PG Vice President 19 o o o o D D o o D o o o D o o D o o o References Medearis, K., The Development of Rational Damage Criteria for Low-Rise Structures Subjected to Blasting Vibrations, in Proceedings of the 18th U.S. Symposium on Rock Mechanics, 1-16, and (1977). Nicholls, H.R., c.F. Johnson, and W.l. Duvall, Blasting Vibrations and their Effects on Structures, U.S. Bureau of Mines Bulletin 656, (1971). DuPont, Blasters Handbook, Technical Services Division, E.l. DuPont, Wilmington, DE, (1977). Dowding, CA., Blast Vibration Monitoring and Control, Prentice Hall, Englewood Cliffs, NJ, ( 1985) International Society of Explosives Engineers, Blasters' Handbook (171h ed.), ISEE, Cleveland, OR (1998). National Highway Institute, Rock Blasting and Overbreak Control. US Department of Transportation, Federal Highway Administration, Publication No. FHWA-HI-92-001, (1991). Reil, lW., D.A. Anderson, A.P. Ritter, D.A. Clark, S.R. Winzer, and A.J. Petro, Geologic Factors Affecting Vibration from Surface Mine Blasting, U.S. Bureau of Mines, Mining Research Contract Report H0222009, (1985). Siskind, DE, Vibrations From Blasting. International Society of Explosives Engineers, Cleveland, OR (2000). Siskind, D.E., M.S. Stagg, J.W. Kopp, and C.H. Dowding, Structure Response and Dama~e Produced by Ground Vibration from Surface Mine Blasting, U.S. Bureau of Mines RI-8507, ( 1980). Siskind, DE, V,j. Stachura, M.S. Stagg, and J.W. Kopp, Structure Response and Dama~e Produced bv Airblast from Surface Mining, U.S. Bureau of Mines RI-8485, (1980). Stagg, M.S., DE Siskind, M.G. Stevens, and CH. Dowding, Effects of Repeated Blasting on a Wood-Frame House, U.S. Bureau of Mines RI-8896, (1984). 20 o D D D D D o o D D o o D D D o o o o Appendix A IsoSeismic Study Maps and Results 2l ~ D D a ~ D ~ ~ ~ D D D ~ o o D o ~ D ?vlartin iVlarietta Aggregates North Indianapolis Quarry ) ndianapolis, Indiana IsoSeisiVibraLVIHp Study i"hl)' 20, 2005 SeiSI110graph Distribution lVlap (,0110 o 1500 3HlHl 451l1J 1 inch ~ 1500 feel' ,,)../V' VIBRA- TECH ENGINEER~:u:~~~. "",."'''''''' ......"'hy<.c.irs Figure A-I ~ [I II o o ~ ~ o Q D o o o o ~ ~ Q o o ~ l\:lartin l\larictta Aggregates North Indianapolis Quarry Indianapolis, Indiana IsoSeis/Vibra!\'lap Study IsoSeismic Contour lVlap of Peak Particle Velocity for Sianature Blast 1 b lVlay 20,2005 r-- 1500 3uoo ~5tJ(J I inch w 15<llt f~ef; o Mll}U -\{"A^ VIBRA-TECH ENG1NEER~:;,.!~~;. .n'I"'~"'> _ "ldovl.",e"" Figure A-2 -- D o D D ~ D D ~ ~ Q a ~ ~ D D D D D o l\-tartin :\larictta Aggregates North Indianapolis Quarry Indianapolis, Indiana IsoSeis/Vibral\lap Study IsoSeismic Contour l\'lap of Peak Particle Velocity for Production Blast 1. l\lay 20, 2005 (J I $Il(j 3(JUO ';5,IU I inch - I $Ilfl ('<'1 (,l)(liI ~'llV' VIBRA~ TECH ENGINEER~t~}!.~S.:-:-"".;,,,<,,> ',;""'1"""""" Figul'c A-3 - a o D o ~ D ~ ~ o ~ o ~ ~ a ~ o o D D 1\'1m-tin :\:larietta Aggregates ~orth Indianapolis Quarry Indianapolis, Indiana IsoSeis/VibraIVlap Study IsoSeismic Contour i\lap of Peak Particle V clocity for Production Blast 2 l\lay 20, 2005 il ..... 15(11) ;J(jOO ..51Ki 1111<:11 = I SUO felif 60no -v\j\',VI BRA-TECH E NGtNEER;:..~~S: . e"'I"...~" . '1'-"P"V';'C,<:' Figure ;\-4 D D ~ ~ D D ~ ~ D D 'D Q ~ ~ ~ D o D o \'lartin IVlarietta Aggregates North Indianapolis Quarry Indianapolis, Indiana IsoSeis/Vibral'Vlap Study Predicted Peak Particle Velocity for Production Blasting in l\'IueUer I)roperty South (Utilizing Current Blast Design) o 1500 Joon 45~) I ioch - 15UO fe~l MOO ,,1t VIBRA- TECH ENGINEER~.J~~;. ""gmwo. g"~'''''l'''CI<'' Figure A-5 ~ ~ 0 0 ~ ~ D a ~ ~ u CJ r,n --- c: .- .... ~ ?-;. ...... .- u 0 - C) ~ ;>- ('"j - C,j -,0 D :.. CI:l Q,. ~ D ~ ~ ~ 0 0 ...... 0.01 1 Comparison of Blast Vibrations Measured at Residential & Commercial Structures to Current U.S. Bureau of Mines Recomnlendations lVlartinMarietta Aggre~ates, North Indianapolis Quarry Signature Blast lVlay 20, 2005 10 I e Signature 1 I 2.(Hn/scc 1 O. 75 ~n/~cc , Drywall . , , , ' - - - 0:50 'inNcC-' -; ~ -, - q -- .. ' ., Plaster ~' .~--_._-~--~--_.~~-~ 0.1 . ,0- .. ' : 0 ;. 0: G I , .e I '... . v,. .' " : -.-- ..... ; ,C, .' ; -8 flr- fj .. __. CJ ~.I.:"~ e.-.,-: "8041)" a ' f? 8. CD · eO'.... 08 0$,: ....... ...:... eo: , eeo-~--..... 10 100 VIBRA- TECH Frequency, Hz Figure A-6 geologists ~ engineers - geophysicists a ~ o ~ ~ D ~ ~ D :0 ~ ~ D D ~ o D D D u 1 Q.J [IJ ---. c= .- ~ .- u o ~ > ~ ....... u .- ..... .. ~ ~ 0.1 0.01 1 Comparison of Blast Vibrations lVleasured at Residential & Commercial Structures to CUITent U.S. Bureau of ~lines Recommendations lVlartin Marietta Ag~regates, North Indianapolis Quarry Production Blasts lVlay 20, 2005 10 . Production 1 . Production 2 ,0.75 in/see ,Drywall - . .. 050 -Hllke' - - - ; , . . . . . . Plustcr ,,' · _______M__wa___..__, . .1 "# ; " e.. . . 10 VI BRA- TECH Frequency, Hz 2.0: iJ1~SCC : ., G . , ,. I e: e .: .ff:" .~ . . '. -..ft..: ; .:,~ ~-:. " 0:" ~.- :0:1: .e .:e:.: . . . : "0 .. 100 Figure A-7 geologists - englne~rs - geophysicists D D D 0 D D 0 ~ - .... - Q ,J., - 0 ", .- "" ;;.- ~ -1 0 ~ - - ... V! 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"" ~ 12~ t:" ~ ;.. o :.. 125 < I:::l I::J ~.......'.'. ~ E] I::J t:::J I:::J I::J E:J E:J I::J I::J EJ I::J t=J Ail" ()verlll"CSSUt"e Levels fl"om 1\-lal1in Marietta Aggregntcs, NOJ1h Indiamll)olis QmuTY Production Blast I !'vlay 20, 200S 134 133 Ai)'. OH:rp)'css_lu:.C n.~c()mI11.rnd~!1 inlj$~M R!-IW:s5 \3\ 120 1\1 ~~~~~~~..$;~~~~i=-'~~=~~w~~~m~Q~~ii-g~~:~t~~~~~i~e~~~~~-~~..~~~~t;~ -t'T"'T...,....,..,....,...,...,......,.""'M'~...,....,...,.~~~~~~:.~..:;.&/~.:~..:~~~,:)..:,;~~-:.~..;;...:....:~>:;I.::.~.:;,..:;..:,.~~~~~~~.;;~-~~~~~O_~_-.,:...:~.;:....::~.:;..:;.~-"'.:;.:;:~...::.~.:~.:.~~~..::. "\'uh-: \if O~i."flt"'''''IJn l.t"HI HI-'l<umnU'lliJ..tI ilt ISIi\f IU.M.tS.; (LU tin-l .\ir O\('rrr""un' L~'Hl H."lIUirl'l1111 Crud, \\ indu'<\ J>;H1\" \ 1~1 dlh . Pl"lltlurlio/J \ VIBRA-TeCH geo ogls S . engmeers - geop YSIClstS Figure A-9 CJ I::) lUllS 0.11I-\. lUlU 0.1112 11.1111 (1.111 ;r.. U.OUl) '" ,.... '-' ... O.OU~ -: '" "0 '" (1.11(17 ~ 'I.. "- :: 0.00(. ..,. ;- "0 0.00:" :::. IUII.l.J.. ( UJ(jJ. 0.0112 0.001