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Army Engineer-2007

Page

111334-352546316365Inside Front2124Inside back

~ ..rBUILD!NG TliE l

LIBBY lUUnGE I

1

1

Plus Magazine's Standard Sections

AE Awards on Page 10AE News & Info beginning on Page 12

AE Industry Support beginning on Page 22

Cover: Members of Company "e; 84th Engineer

Construction Battalion, U.S. 8th Army, lower a 40-foot

steel pile used for a bent cap, into the water to be

power-driven 22- feet into the Imjin River bed dur-

ing the reconstruction of the Freedom Gate Bridge

at Munsan-ni, 16 Oct , 952. Note the "cost" of the

crane painted on the side of the cab (S17,915). This

was only one bridge constructed by the 84th dur-

ing the Korean War. Construction of the complex

concrete Libby Bridge (see feature article) was

one of the toughest bridge projects ever tack-

led by Army troop unit engineers. (Photo from

Army Center of Military History)

January-February Page 3

oninvasive engineering

geophysical surveying

technologies can provide

military engineers with timely

and critical information related to

infrastructure design, planning,

construction, and/ or remediation.

Geophysical methods are particularly

well suited to construction efforts on

airfields, bridges, buildings, roadways

and dams, often in austere environments

and with abbreviated timelines. In

contrast to boreholes and trenching,

the greatest advantage of noninvasive

geophysical methods is the ability to

effectively test much larger volumes of

the subsurface.

Recent case studies are presented herein, in an effort todocument applications of geophysical technologies to mili-tary-type projects in an effort to save time, reduce costs andimprove the product. Some of these geophysical projectswere very successful; some simply provided valuable "les-sons learned". In some instances, the geophysical "deliv-erables" allowed the subsurface to be reliably imaged in atimely manner without boring and trenching, which canbe an important consideration at sites where time and/orconditions preclude the use of drill rigs or other invasivetechnologies. The ability to leverage geophysical methodsis predicated on the military engineer confidently under-standing the strengths, limitations and applications of therespective tools.

The U.S. Army Corps of Engineers employees (bothmilitary and government service) are actively involved inmany infrastructure projects that would benefit if geophysi-cal methods were routinely employed for site assessment.In an effort to inform and assist USACE engineers, on-linepublications, solution matrixes, and geophysical resourcesare referenced in this article. It is urgent that information

Army Engineer-200?

about potentially useful geophysical methods be widelydisseminated to ensure that these potentially cost-effec-tive technologies are considered by those responsible forrebuilding highways and other infrastructure damaged byconflict or neglect.

Expedient combat engineering construction methods~ are routinely used to repair ports of entry and lines of com-

munication in order to re-establish civil order and rudimen-tary life support whether from natural disaster or conflict.The purpose of this article is not how to insert geophysicalmethods into such operations. Rather, it is how to makethese technologies available to the Commander's EngineerStaff in order to facilitate the assessment of damage andthe repair of critical infrastructure. During follow-on op-erational phases, these tools can also assist in rehabilitationof broader and more extensive infrastructure.

EXPEDIENT APPLICATIONS OF GEOPHYSICS INCONTINGENCY ENVIRONMENTS

Some geophysical methods are well established androutinely used within the military engineering community.Particularly noteworthy is the use of seismic cone pen-etrometers, falling weight deflectometers, and ground pen-etrating radar (GPR) for competency studies on AirfieldConcrete Runways by the Air Force Civil Engineering Sup-port Agency located at Tyndall Air Force Base, Florida.One of its missions is to deploy world-wide to evaluatepavements in support of contingency flight operations.GPR was also used by the U.S. Army to locate mass gravesand weapons caches (Figure 1 below).

In part,this technol-ogy wasimplementedwhen an En-gineer StaffCaptain rec-ognized thatGPRcouldbe success-

..._- fully used to"- image and

map suchanomalous

conditions. The Captain reached back to the United Statesto find a geophysical firm that could deliver this systemand train operators.

The use of geophysical methods to evaluate pier struc-tures at neglected port facilities is another example of arapid, inexpensive and proven technology. The focus ofthese investigations is typically to determine the length ofpiles and assess the integrity of the concrete, particularly inthe upper sections of the piles. In one case, both crossholesonic logging and sonic echolimpulse response methods

January-February Page49

determined no major defects of tested piles on a 'synchro-lift' pier resulting in significant cost savings for rehabilita-tion rather than reconstruction. Another method known asrefraction micro tremor (ReMi) was applied to an earthendam investigation that resulted in remediation that avoidedpotential catastrophic outcomes.

Some geophysical applications have not met with suchresounding success. In one after action review, the capaci-tively-coupled resistivity meter (ground based resistivity)was determined to lack the capability to locate sewers andother voids in urban areas because the array length con-strained its application. On some occasions, the geophysi-cal image of buried trash and subsurface geologic featuresmimicked those normally associated with voids, caus-ing the supervising engineers to loose confidence in themethod's ability to deliver reliable information in a timelyand safe manner.

Also of interest is the capability of geophysical tech-nologies to identify the source of leaks from public worksdrinking water pipes. The Gulf Region Division noted thatabout 40 percent of fresh water in Baghdad, Iraq, was lostdue to broken pipes between the water pumping stationsand the inhabitants. Similarly, a former a Project Engineer

involvedin earlyoperationsin Kosovo,recallssendingout welldrillingtrucks tofind po-table watersourceswith suf-ficientcapacityto supportlarge per-sonnel basecamps.

He recalled that each iteration of exploratory drilling costabout $20,000 using a trial and error method. In retrospect,the geophysical application of a (time-domain) electromag-netic method could have been leveraged to reduced timeinvolved in finding underground aquifers as well as leaks inpipes (Figure 2 above).

Figure 2: The instrument shown is a handheld, digital, pro-grammable, broadband electromagnetic (EM) sensor thatis sensitive toearth's electrical conductivity and magneticsusceptibility. .

DETERMINING DEPTHS OF SHEET PILES INNEW ORLEANS

The use of noninvasive geophysical methods hasgarnered national attention in several notable cases. Suchcases demonstrate both the capabilities and the limitations

January-February Page50

of these technologies, emphasizing the need for furtherresearch and development in their employment. One suchexample is the application of geophysical methods to con-duct forensic studies to determine the cause of levee failuredue to Hurricane Katrina in the city of New Orleans,Louisiana in 2005.

The drainage canals of lower New Orleans wereoriginally constructed between 1833-1877, when the areabetween downtown New Orleans and Lake Pontchartrainwas a series of densely foliated cypress swamps. The leveesalong the drainage canals were raised using earth fill ontwo occasions, following damaging hurricanes that causedflooding in 1915 and 1947. Between 1945-75 the swampswere drained and the area was intensely developed adja-cent to the drainage canal embankments. Between 1992-96concrete flood walls approximately 10 ft high were con-structed on the crest of the drainage canals and Inner Har-bor Navigation Channel (IHNC) to protect the city fromstorm surges up to an elevation of 14 ft above mean gulflevel. These 10 ft high flood walls were constructed upon

segmented Figure 3: South end of the 17th Street Canal levee breach insteel sheet New Orleans. The base of the concrete t-wali was removedpiles that ex-from the supporting steel sheet piles in December 2005 after

tended 10 to geophysical tests suggested that they were 6 to7 feet shorter

25 feet into than specified. Photo by.). D. Rogers.

the leveesand their foundations (see figure 3 above).

When Hurricane Katrina struck New Orleans onAugust 29,2005, a number of these "l-walls" situated onearthen levees failed when water levels came within about3 to 4 feet of their crests, well below their intended designcapacity (Seed et al., 2006; IPET, 2006). Eyewitness ac-counts alleged that the drainage canal walls were not over-topped prior to their collapse, triggering speculation thattheir design was inherently flawed. In the weeks followingthe hurricane-induced floods, local newspapers began run-ning lurid exposes alleging malfeasance in local corps flood

Army Engineer-200?

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Figure 4 Top: Parallel Seismic Test schematic. Note that the cased hole withthe hydrophone needs to be within 3 to 5 feet of the embedded steel elementsand cased to a depth about 15 feet deeper than the element being analyzed.Diagram from Olson (2005).

Figure 5Right: Typical section through concrete flood wall used along the 17thStreet drainage canal in New Orleans. These nominally 1O-foot high walls wereconstructed on top of earthen levee embankments in 1993. A 550 ft section ofthe flood wall slid laterally, spilling water into the Lakeview area. Post-failureanalyses suggest that the wall failed when the flood surge rose to within 4 feetof the wall's crest. Taken from US Corps of Engineers (1990).

control projects, quoting construction workers who allegedthat their firms knowingly installed "short" sheet pilesbeneath some of the concrete flood walls.

In October 2005 the Corps of Engineers contractedwith Olson Engineering of Wheatland, CO to employNondestructive Testing methods (NDT) to ascertain thedepths of the Hoesch 12 sheet piles used along the 17thStreet, London Avenue, and Inner Harbor Navigation ca-nal flood walls (Olson, 2005)_Olson Engineering had con-siderable experience using parallel seismic tests to ascertainthe depth of buried steel H-piles beneath the ground,but had never employed the method previously on sheetpiles. H-piles are dense structural elements driven into theground using conventional pile drivers and commonly usedas foundation elements for heavy structures. Sheet pilesare very thin (7/16 in. in New Orleans), discontinuouselements installed like an underground curtain. They arejoined via mechanical interlocks, not contiguously con-nected like welded structural connections.

Army Engineer-200?

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The parallel seismic method employs an instrumented3-pound hammer as a source of input energy, a singlehydrophone receiver, and a dynamic signal analyzer. Thespatial requirements are shown schematically in Figure4. Many of the concrete flood walls in New Orleansemployed an asymmetric structural cross section, withadditional concrete cover extending down the water-sideof the wall, as shown in Figure 4 above. The walls werecomprised of reinforced concrete stems 12 inches (in.)thick, increasing to 24 in. around the 10.5 in. wide sheetpiles (Figure 5 above).

January-February Page51

The cased hole provided to Olson to use for their hydro-phone was situated about 7-1/2 ft from the wall (Figure 6below), and was only cased to 25 ft of its 50 ft depth. Un-known to Olson, this created a situation where the casingonly extended 12 to 18 in. below the sheet piles tips, notthe 15 ft normally used in such tests. The parallel seis-mic tests were performed using a 3-lb hard plastic-tippedinstrumented hammer (Figure 7 below). Five strikes of thehammer were employed for each depth interval of the sub-

mergedhy-drophones,startingat -25 ft(bottom ofthe PVCcasing) andraising thephonesin 12 in.incrementsto holecollar atthe crest of the earthen levees. The input energy from the3-lb hammer was dissipated within the concrete sheath-ing around the sheet pile heads, with very little energytraveling down the individual sheet piles. Despite the weaksignal, Olson Engineering and Southern Earth Sciences,Inc. (SESI) of Baton Rouge (working for Team Louisianaat LSU) independently estimated the depths of the sheetpiles to be 13 to 15 feet below the levee crest, which cor-responded to about 10ft below mean gulf level. This was5 to 7 feet shorter than specified in the 1993 constructionspecifications, which specified pile tips at -17 feet.

The results of the parallel seismic test geophysical sur-veys garnered nation-wide media coverage, and charges ofmalfeasance grabbed newspaper headlines and the integrityof the Corps of Engineers was questioned. Several of the

Figure 6 Top left: Southern Earth Sciences advancing a conepenetrometer sounding within 3 feet of the 17th Streetflood wall shown in Figure 2 in January 2006. The PVC casedboring used in the October 2005 parallel seismic tests is seenabreast the track mounted rig, about 7-1/2 ft from the wall.Photo by Olson Engineering.

Figure 7 Top right: Left photo illustrates hammer energy be-ing tapped into base of one of the concrete t-walls by OlsonEngineering in October 2005. These tests were complicatedby a very weak signal making it through the concrete shellencasing the sheet pile cap, and down to the pile tips. Photosby Olson Engineering.

January-February Page52

contractors involved in the original construction vehement-ly denied any measure of malfeasance, offering to pull theallegedly short sheet piles out of the levees and allow themto be measured directly. The Corps' Interagency Perfor-mance Evaluation Task Force (IPET) appointed to inves-tigate the damages caused by Hurricanes Katrina and Ritaconsidered the contractor's offers and wisely gave the go-ahead for pulling of the sheet piles adjacent to the failuresites. On December 12, 2005 the Corps of Engineers had alocal contractor chip off the intact concrete I-wall poured

over the steel sheet piles along either end of the 17th StCanal breach (Figure 3), adjacent to where the parallelseismic tests had been performed by both consulting firms.

The following day four sets of sheet piles were pulledfrom either end of the 17 Street Canal breach site, in pairsof two sheets each. All the major news services covered thepull-out tests, which was a unique news event, in and of it-self. To many peoples' surprise and chagrin, all of the sheetpiles were about 23'-6" long, slightly longer than requiredin the 1993 construction documents! The headlines of ma-jor newspapers on December 14th reported that the sheetpiles met the contract specifications and that allegations ofmalfeasance were, therefore, false. The Corps of Engineersand the local contractors felt vindicated, even though thesheet piles were of inadequate length to cut off the under-seepage that led to the wall's untimely failure.

Everyone's curiosity then shifted to figuring out howboth consultants could have been wrong. Olson Engineer-ing and Southern Earth Sciences, Inc. (SCIC) of BatonRouge revisited New Orleans in December 2005 at theirown expense, determined to unravel the causes for theirerrant measurements and see if they could obtain reliablevalues for the sheet pile depths. SESI brought in their ownGeoProbe 6625 CPT rig (Figure 6) to advance sound-ings (boreholes) closer to the sheet piles, and cased theseto depths> 15 ft below the sheet pile tips, as originallyassumed in Olson's stated protocol (Figure 4). The con-sultants began by varying the input energy and examiningthe hydrophone signatures (right side of Figure 7). They

Army Engineer-2007

soon discovered that the long curtain-like nature of thesheet piles dissipates energy dramatically, up and downthe wall, minimizing that portion of the energy availableto travel vertically, down the one sheet pile section closestto the cased borehole (each sheet was only 22.64 in. wide,between interlocks).

By comparing results of the concrete encased sheetpiles and those exposed the previous month, it soonbecame obvious that significant energy loss occurred inthe asymmetric concrete cap (Figure 5) into the surround-ing foundation soils and discontinuous sheet piles. Themost effective hammer techniques were realized whenthe impact was made directly on top of the flood wall sill,directed downward and using a steel rod in direct contactwith the exposed sheet piles, circumventing the concretecap. On the IHNC walls Olson excavated access trenchesthat allowed direct impact of their instrumented ham-mer against the sheet piles and this gave good results, butrequired much more work. The least effectivemethod wasthat employed in October 2005, pounding on the widenedconcrete encasement at the base of the concrete l-wall(Olson, 2006).

The importance of close separation between the actualsheets and the cased borehole was also validated, as wasthe need to carry the casing well below the pile tips, socontrasts in the acoustic signature could be ascertainedboth when the sheets were close to the hydrophone andwhen they were not. All of these factors combined to resultin erroneous conclusions about the pile tip depths in theOctober 2005 tests. Had the casings been carried downanother 15 feet, as suggested by the consultants, the resultsmight have been more accurate.

FLUXGATEMAGNETOMETER METHOD IN PORT OFLONG BEACH

In 2005-06 a similar series of tests were carried out withthe cooperation of the Federal Highway Administration's(FHWA) NDE Validation Center on an existing steel sheetpile bulkhead wall along the Back Channel in the Port ofLong Beach, California, which was slated for widening.Since the actual depth of the sheet piles were unknown,three geophysical methods were compared to ascertainwhich would yield the best results. These methods in-cluded: 1)magnetic susceptibility, 2) electrical induction,and, 3) fluxgate magnetometer methods. Logging wasperformed from three PVC-cased boreholes drilled within 3feet of the bulkhead wall. The geophysical logging meth-ods and results were recently summarized by Jalinoos(Jalinoos et aI., 2006.)

The fluxgate magnetometer gave the clearest and mostconsistent results, using the methodology proposed by Joet al. (2003) of the FHWA. Since steel sheet piles are fer-romagnetic, they can generate an induced magnetic fieldin response to the earth's geomagnetic field. If the induced

Army Engineer-200?

magnetic field is generated by steel embedded in the sheetpile curtain, it can be measured within a borehole, pro-vided it is located in close proximity (3 ft) to the sheet piles.If the borehole extends appreciably below the sheet piletips, the depth of the closest sheets can be determined withremarkable accuracy.

The fluxgate magnetometer method uses a borehole"deviation probe" containing a 3-axis fluxgate magnetom-eter and a 3-axis accelerometer in a 4.6 in. long casing.Data collected by these probes are usually combined withdownhole microprocessors to provide real-time, continuouslogs of probe orientation and borehole inclination/ direc-tion. This ability is important insofar as boreholes areseldom perfectly plumb, and divergence between the casedborehole and the steel sheets can alter test results. The mu-tually orthogonal (x, y, and z axes) fluxgate magnetometersmeasure the magnetic field in each of the component axes.Three piezo electric accelerometers measure gravimetricacceleration, on the same orientation as the magnetom-eters.

The tips of the sheet piles were interpreted as a de-crease in magnitude of the magnetic field. On the plotsof soil conductivity and magnetic susceptibility, sheet piletips were indicated as points of inflection of the decreasingcurves (Figure 8 below). The magnetic field magnitude isshown in red, electrical conductivity in green, and mag-netic susceptibility in blue. The depth in feet, is shown on

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January-February Page53

Figure 9. (a) The outline shows the geophysical survey area dimensions atroughly 350 feet north-south and 500 feet east-west, (b) where the survey waslimited by thick forest vegetation and steep slopes. (c) Geophone lines are cross-ing a road on the slope of the survey area. Figure 70 right:. Geophysical surveyarea showing seismic lines (blue), and geotechnical borehole locations (yellow).The base map shows a proposed layout for six new condominium buildings(red). (Sirles,2006) (Composite photo and graphic by authors).

the vertical axis. The magnetic field indicates the compassreading magnitude, which is highly sensitive to the pres-ence of steel as it deviates from its true (nonperturbed)value. In the same vein, the electrical conductivity is in-fluenced by the conductivity of the surrounding soil. Bothlogs are highly sensitive to the presence of steel. Placingthe instrument borehole close to the sheet piles and record-ing magnetic field and conductivity from ground surfaceto a depth well below the sheet pile tips have resulted inhighly accurate depth estimates, to depths of 70 ft (Jali-noos, et a1.,2006).

GEOANALYSIS IN CONSTRUCTION PLANNING

Three Dimensional (3D) subsurface modeling is arelatively recent but important development that can assistmilitary and civil engineers, particularly those engaged inthe design of large construction projects. The geophysicalsurvey presented here represents a case where cutting edgemodeling saves the builder time and money through designoptimization and hazard mitigation. In the spring of 2005,geotechnical borings were placed in accessible areas ofa proposed multi-level condominium complex located

January-February Page54

adjacent to a ski slope at Vail, Colorado (Figure 9 aboveleft). Geophysical exploration used seismic refraction toinvestigate and supplement other geotechnical data. Theobjectives of the survey were to map the top of bedrock,determine thickness of overburden soil, and evaluate thevariability the soil and the competency of the bedrock.

During the seismic refraction survey, GPS coordinateswere acquired for most of the geophone and shot locations;however a few positions were interpolated due to poorquality GPS data obtained in the trees. Seismic refractiondata were acquired using twenty-four 8-Hz vertically-po-larized geophones at 10 foot spacing and a hammer/platesource. Figure 10 above depicts a site map, identifying the

Army Engineer-200?

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locations of nearby buildings, available geotechnical bor-ings, and the seven seismic refraction lines.

Application of seismic refraction surveying to charac-terize the subsurface is nothing new. Conventional practicefor the last thirty years has been to process refraction datawith layer reconstruction techniques using generalizedtime-intercept techniques. Advancements in data process-ing make it possible to model the subsurface with greaterfidelity and in 2.5Dimensions. The term 2.5D is usedbecause we use a Bessel function (b-spline) interpolationalong the known refraction survey lines and between thelines with known borehole logging control to create a 2.5DModel or an interpolated virtual 3D model.

The procedure and software application used to modelthe subsurface in this case is termed the GeostructuralAnalysis Package (GAP) which, in its initial stages ofdevelopment, has been optimized for geotechnical applica-tions such as 2D and 3D seismic refraction data processingand presentation on engineering projects (Sirles, 2006). Thevalue of using this approach for seismic applications is itsability to produce 3D models to assist engineers or geolo-gists extract additional information from the geophysi-cal data (e.g., material properties), or perform static anddynamic stress analysis (Figure 11 above).

The Vail model was built by determining the top ofbedrock which is typically a primary objective of a geo-physical survey, but was not the principal engineeringpurpose of this site investigation (e.g., construction of a

Army Engineer-200?

Figure 11. (a) 20 refraction survey line allows for computations that determineboth lateral and vertical changes in velocity. (b) Velocity slices are derived from20 refraction and boreholes and are the basis of generating a 2.50 Isopachmodel. (c) Software such as GAP converts velocities and loads into a static anddynamic stress model. (d) The soil area within the model is removed simulatingexcavation. (Sirles, 2006)

critical facility, design of a foundation for a structure, etc.).With ever higher-quality calibrated 2D, 2.5D and 3D mod-els, engineers are more likely to use the seismic results byincorporating them directly into their engineering analy-ses. Results from this case study demonstrated the benefitof assessing seismic refraction data using software witha numerical modeling approach. In Vail, Colorado, theengineering firm using this geophysical modeling approachwas surprised to see that thick soil and hard rock werealmost exactly where the survey had predicted. Moreover,the construction plan implemented slope stability hazardmitigation based on this analysis. At the conclusion ofthe excavation phase of the Vail, Colorado ConstructionProject, Mr. Phil Sirles of Zonge Geosciences commented"Having established credibility with the Engineering Firm,the lead Engineer approached me and commented that oursurveys are now looked upon as an investment rather thanan expense by management."

LEVERAGING ENGINEERING GEOPHYSICS

We recognize that there are many research laboratoriesthat continue to refine and offer specialized geophysical

January-February Page 55

method services. However, we also recognize that indus-try, academia, and other branches of the government mayalready hold geophysical solutions to civil engineeringproblems to which other sectors are not aware. The stepsoutlined below are intended as an approach to select geo-physical methods to assess sites that ultimately contributeto more efficient construction planning.

1. Similar to Engineer Manual 1110-01-1801, Ap-plications of Geophysical Methods to Highway RelatedProblems (Hanna et al, 2003) is a more recent primer thatprovides a basic understanding of geophysical methods,their advantages and limitations: It can be accessed on-lineat: http://www.cflhd.gov/agmlindex.htm.

2. There are several tables derived from AmericanSociety for Testing and Materials (ASTM) guidelines thatprovide an overview of common geophysical methods andtheir respective applicability to site conditions. Selection ofmethods and their application should be done by qualifiedprofessionals. The solution matrix below (Table 1), thoughnot exhaustive, can be applied to civil engineering prob-lems typically faced in a contingency environment:

3. A list of geophysical firms along with their capabili-ties is provided in Table 2 for consideration by Staff Engi-neers as a resource. The capabilities are listed by geophysi-

Table 1

cal method or a consultant which implies the capability toemploy multiple methods. Firms listed are registered in theUnited States Government's Central Contractor Regis-tration and can accept electronic payment that supportscontingency contracting requirements.

LTC Niklas H Putnam works for the Department of theArmy, stationed in Washington, DC and is a Professional Geolo-gist. LTC Putnam is also a PhD Candidate in the University ofMissouri - Rolla (UMR) Geological Engineering (GE) DistanceLearning Program. Dr. J David Rogers is a Professor at UMRin the GE Program and is the Karl F Hasselmann Chair. Heis a Professional Engineer and Professional Geologist. Specialacknowledgement is made to Dr. Neil Anderson, Professor in theGE Department at UMRfor his collaboration in this work. Wewould like to recognize Mr. Phil Sirles of Zonge Geosciences,Incorporated of Lakewood, Colorado as well as Mr. Dan Feeneyof Vail Resorts Development Company are thanked for grantingpermission to include graphics and data from the Vail, Colorado,case history. The authors also acknowlege the assistance of LarryOlson of Olson Engineering in Wheatland, Colorado for provid-ing photos and graphics illustrating their work in New Orleans.REFERENCES USED PROVIDED UPON REQUEST TOAUTHORS.

SELECTION OF SURFACE GEOPHYSICAL METHODS FOR COMMON APPLICATIONSAdaptedfor MilitaryEngineeringfromASTMD6429StandardGuidefor SelectingSurfaceGeophysicalMethods,copyrightASTMInternatlc

ASTMInternational,100BarHarborDrive ConshohockenPA 19428"SEISMIC ELECTRICAL ELECTROMAGNETIC OTHER TECHNIQUES I'

Surface Frequency Time HAPPLICATION Refraction Reflection Waves Resistivity Domain Domain VLF GPR Magnetics GravityNatural ConditionsSoil/Unconsolidated Strata A B A A B A B A · ·

Rock Strata B A B · · · · B · · HDepth to Bedrock A A,r,", A B B B B A · BDepth to Water Table : A,:, ,,::I.f"'AJ,':i · B B B B A · · 'F'

Fractures and Fault Zones B B · B A B A A · BVoids/Sinkholes/Caves B · A B A · · A · ADarn/t.aooon Leakaoe · · · B B · · B · ·

(Brldoe) Scour/River Bottom · B · · · · · B · ·Contaminants

Landfill · · · A A A B B · ·Saltwater Intrusion · · · A ,iF 'A A B B · ·

Soil Salinltv · · · A '<A · · · · ·Light (Non-AQueous) Phase Liquids · - · B B B · B · ·

EnaineerlnoUtilities - · · · B A · A · ·

(Oil & Water) Pipeline Leaks · · · · · · · B · ·Drums/USTs · · · · A · · A A ·

Earth Dam/Levee/Abutment B · B · · · · · · ·Piles · B · · · · · · · ·

Forensics / Archaeological · · · B A · · A B ·Concrete/Asphalt Thickness · · B · · · · A · ·

• A - Implies a primary choice of method; B - Implies a secondary choice or alternative method,

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January-February Page56 Army Engineer-2007

Table 2

Blackhawk, www.zapeng.com, khanna@zapeng.com, Consultant301 Commercial Road, Suite B; Golden, CO 80410; 303-215-5465DGSI, www.durhamgeo.com, Imiller@durhamgeo.com Materials Testing902-A Scorchie Dr; Marion, IL 62959; 618-998-0011FDH Engineering, www.fdh-inc.com,dfarinella@fdh-inc.com GPR2730 Rowland Rd; Rayleigh, NC 27615; 919-755-1012Fugro Airborne Surveys, www.fugroairborne.com, bbrown@fugroairborne.com Airborne2270 Amentia Road; Mississauga, ON LSN 6A6; 905-812-0212GEL Geophysics, www.qel.corn, kate.mckinley@gel,com Consultant2040 Savaqe Road; Charleston, SC 29403; 843-769-7378Geometrics, www.geometrics.com, sales@geometrics.com Electromagnetic2190 Fortune Drive; San Jose, CA 95131; 408-954-0522Geonics, www.geonics.com, geonics@geoinics.com Electromagnetic1745 Meyerside Drive; Mississauqa, ON, L5T 1C6; 905-670-9580Geophex, www.geophex.com, sales@geophex.com Electromagnetic605 Mercury Street; Raleiqh, North Carolina 27603; 919-839-8515Geotechnology, www.geotechnology.com, dJambert@geotechnology.com Consultant11816 Lackland Road, Ste 150; St. Louis, MO. 63146; 314-997-7440Geovision, www.geovision.com, jb@geovision.com Consultant1151 Pomona Road, Suite P; Corona, CA 92882; 951-549-1234GISCO, www.giscogeo.com, sales@giscogeo.com Consultant6323 Cambridge Dr.; St. Louis Park, MN 55416; 952-929-8000GSSI, www.geophysical.com, parillor@geophysical.com GPR12 Industrial Way; Salem, NH 03079; 603-681-2059Hutchinson Group, www.geo-image.com, pjh@geo-image.com Consultant4280 Old William Penn Hwy; Murrysville, PA 1568; 724-325-3996Mala, www.malags.com, sales.ura@malags.se GPRPO Box 80430; Charleston, SC 29146; 843-852-5021Optim, www.optimsoftware.com, admin@optimsoftware.com Seismic1664 N. Virginia Street, MS 174; Reno, NV 89557; 775-784-6613SAIC - Geophysical Services, www.saic.com/geophysics, richard.a.hoover@saic.com Consultant6310 Allentown Blvd; Harrisburg, PA 17112; 717-901-8835Schnabel Engineering, www.schnabel-eng.com, nbillington@schnabel-eng.com Consultant11-A Oak Branch Drive; Greensboro, NC 27407; 336-274-9456SCI Engineering, www.sciengineering.com, jrobinson@sciengineering.com GPR4145 S. McCann Ct., Suite F; Springfield, MO 65804; 417-823-0355Seismic Source, www.seismicsource.net, dbraden@seismicsource.net Consultant9025 East Tower Road; Ponca City, OK 74604; 580-762-8233Seistronix, www.seistronix.com, sales@seistronix.com Seismic3299 D Monier Circle; Rancho Cordova, CA 95742; 916-851-1890Technos, www.technos-inc.com, info@technos-inc.com Consultant10430 NW 31 TER; Miami, FL 33172 ; 305-781-9594Terracon, www.terracon.com, sdbowman@terracon.com Consultant1360 GreQ Street, Suite 112; Sparks, NV 89436; 775-351-2400Zonge, www.zonge.com, phils@zonge.com Resistivity3322 East Fort Lowell; Tucon, AZ 85716; 520-327-5501

Army Engineer-2007 January-February Page 57