ELECTROMAGNETIC WAVES and particulate materials

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1 Aussois 2012 ELECTROMAGNETIC WAVES and particulate materials J. Carlos Santamarina Georgia Institute of Technology

2 References: Santamarina, J.C., in collaboration with Klein, K. and Fam, M. (2001). Soils and Waves, J. Wiley and Sons, Chichester, UK, 488 pages. Klein, K. and Santamarina, J. C. (2003b). "Electrical Conductivity In Soils: Underlying Phenomena." Journal of Environmental & Engineering Geophysics, Vol. 8, No. 4, pp Klein, K. and Santamarina, J. C. (1997). "Methods for Broad-Band Dielectric Permittivity Measurements (Soil- Water Mixtures, 5 Hz to 1.3 GHz)." ASTM Geotechnical Testing Journal, Vol. 20, No. 2, pp Santamarina, J. C. and Fam, M. (1997b). "Dielectric Permittivity of Soils Mixed with Organic and Inorganic Fluids (0.02 GHz to 1.30 GHz)." Journal of Environmental & Engineering Geophysics, Vol. 2, No. 1, pp Santamarina, J. C. and Fam, M. (1995). "Changes in Dielectric Permittivity and Shear Wave Velocity During Concentration Diffusion." Canadian Geotechnical Journal, Vol. 32, No. 4, pp Some pdfs (these and related papers) available at under "Publications"

3 Soils: An Electrical View

4 Fluids - Water Mass Bulk stiffness Capillary forces Seepage rate Dipole Hydration and double layers Cl - H o H Cl - C 4+ Cl Cl - O L=1.25r L=10r

5 Electrical View of Soils dry soil water wet soil pore fluid Precipitated salt mineral double layer

6 Wet clay Laponite 1200 H 2 O 24 Na + N. Skipper (UCL)

7 Electromagnetic Waves

8 Maxwell s Equations Gauss' Law of Electricity surf E ds dv free vol free v E 1 v Gauss' Law of Magnetism surf H ds 0 H 0 Faraday's Law of Induction loop d E dl H ds dt surf E dh dt Ampere-Maxwell's Law d H dl J ds E ds dt loop surf surf H E de dt

9 Electromagnetic Parameters Free space Materials Conductivity 0 Permittivity ε o ε* = ε - j ε Permeability o = - j

10 Wave Equation 2 E E t 2 t E 2 in real materials Consider solution of the form (fluctuates in y - propagates in x) E E e e y o x (j t x ) Then j j 2

11 if E E e e y o x (j t x ) Faraday E dh dt * * H j E e j E then j t * x z o y y x z

12 Phase Velocity V ph Im( j ) Im j 2 In free space o o 0 ph o 1 8 m V c 3 10 o o s In non-ferromagnetic dielectric o ' 0 V ph c o ' o

13 Attenuation Re j Re j 2 In free space o o 0 0 In non-ferromagnetic material o ' j " o ' 1 c 2 1 tan 1 o 2

14 Electromagnetic Spectrum Frequency [Hz] Wave Wave length [m] Gamma rays X rays Ultraviolet Visible * Infrared Microwaves GHz MHz Radio waves KHz

15 and God said: E H E H 1 0 free v dh dt de E dt and there was light!

17 Light-surface interaction (Atlanta Airport) and blue butterflies?

18 Reflection Fresnel s Ellipse van Gogh - La Nuit Etoilee

19 Scatter St. Peter - Rome

20 Electromagnetic Material Properties

21 Electromagnetic Parameters Conductivity Permittivity ε* = ε - j ε Permeability = - j

22 Note: Losses Ohmic conduction losses Polarization losses ε ω Magnetization losses ω Non-Ferromagnetic tan " '

23 Conductivity charges & mobility

24 conductivity [S/m] Electrical Conductivity of the Pore Fluid CaCl 2 NaCl NaOH concentration [mol/l] At low concentration (P. Annan): [ms /m] 0.15 TDS[mg /L] fl

25 Archie s Law? soil n el

26 Electrical Conductivity Pore fluid Surface conduction Wet Soil soil n el 1 n g S s

27 mixture conductivity, mix [S/m] Electrical Conductivity of Soils 1 c = 0.1 mol/l soil n fl Archie c = 10-5 mol/l soil n fl 1 n S s porosity, n

28 Summary 10 0 Controlled by (1-n) gs s el= soil soil [S/m] clays Controlled by eln 10-3 S s sands de-ionized water fresh water sea water el [S/m]

29 soil [S/m] Summary: Electrical Conductivity Controlled by (1-n) 2 g λs s el= soil 10 0 Controlled by n el clays 10-3 S s sands de-ionized water fresh water sea water el [S/m]

30 Permittivity Polarizability

31 Single phase Direction of Applied Field Electronic (resonance) Ionic (resonance) Orientational (relaxation) t =10-16 s (Ultraviolet) t =10-13 s (Infrared) - 12 t = 9 10 s (Microwave water)

32 Polarization spectrum spatial ' orientational ionic electronic conduction losses polarization losses " frequency [Hz]

33 Water-Ion Interaction f = 1.3 GHz 70 KCl ' FeCl 3 LiCl NaCl CaCl ionic concentration [mol/l]

34 Double layer effects Direction of Applied Field Stern layer Bound water (relaxation) (Infrared) Double layer (deionized) (Radio frequency) Double layer (electrolyte) Double layer - Normal particle interactions (surface conduction)

35 Two-phase media - Spatial polarization Direction of Applied Field (no relaxation) Maxwell relaxation Wagner relaxation Semi-permeable membrane

36 Polarizations log(size/m) 0 mixture (interfacial polarization - relaxation) macrospace polarization single phase material -3-6 micro-space polarization double layer scatter grain bound. visible range molecular orient. relax ionic reson. electronic resonance log(frequency/hz)

37 Summary: Relative Permittivity ice ~3 most organic fluids 2-6 water 78 air, gasses ~1 minerals n n 1 S ns Linear mixture ' ' ' soil m w 1 n n 1 S ns ' ' ' soil m w 2 CRIM ' 2 3 soil v v 76.7 v Topp et al. 1980

38 Summary: Single materials water 78.5 methanol 32.6 most organic fluids 2-6 quartz calcite most minerals 6 10

39 Permittivity Free Water - Consolidation Orientational Pol GHz 0.20 GHz DeLoor (Table 11.9) ' 30 ' Volumetric local volumetric Water water Content content (a) 1.E+07 1.E+06

40 Summary: Soils VOLUMETRIC WATER CONTENT ' n 7.9 v 2 ' 40 v v v ' v v ' v v v ' v v ' v v

41 real relative permittivity [ ] Summary Kaolinite Bentonite Mixed clays Sands and silts Topp et al. (1980) Based on CRI - S=100% Selig and Mansukhani (1975) Wang (1980) Wensink (1993) volumetric water content [%]

42 Permeability Magnetizability

43 Kingston Fossil Plant (12/22/2008) [Photo: U.S. Environmental Protection Agency]

45 XRD: Mill Creek Hopper Magnetically separated fraction: hematite Fe 2 O 3 (weakly magnetic), magnetite Fe 3 O 4 and maghemite Fe 2 O 3 (both strongly magnetic).

46 Magnetization Electron orbits orbit alignment Diamagnetism Electron spin unpaired Paramagnetism Alignment within domains move domain walls Ferromagnetism domain 1 wall domain 2

47 Permeability iron fillings in kaolinite f = 10 khz μ rel = v Fe + 7 v Fe ' rel 2 Maxwell μ rel = v Fe 1.5 Wagner volume fraction of iron filings

48 Permeability iron in kaolinite f = 10 khz ' rel (a) (b) (c) (d) (e) (f) (g) frequency [Hz] " rel Series1 (a) Series2 (b) Series3 (c) Series4 (d) Series5 (e) Series6 (f) Series7 (g) frequency [Hz]

49 Summary Single materials water, quartz, kaolinite (diamagnetic) montmorillonite, illite, granite, hematite (paramagnetic) nickel, iron (ferromagnetic) '/ o ~ > 300 Predictive relations spherical ferromagnetic inclusions Kaolinite with iron filings (at 10 khz) 1 3v Fe 1 4v 7v Fe 2 Fe for v Fe <0.2 for v Fe <0.3

50 Measurement

51 Testing Quasi-DC Standing wave f res Wave propagation f R, C, L Complex Reflectivity V α

52 Quasi-static

53 Circuit Elements - Impedance Resistor (R) Capacitor (C) Inductor (L) V i R V 1 j i C V i j L Z* V i R j L 1 C Z* V i 1 R 1 j C

54 Laboratory measurements V 1 SG V 2

55 Depth [cm] Laboratory: Electrical Needle SG Varved Clay 0 V S R fix V N X-Ray Resistance [k ]

Depth [cm] Depth [cm] Lab-scale 0 0-1 -1-2

8 Resistance [k ] -10 2 4 6 8 Resistance [k ]

56 Depth [cm] Depth [cm] Lab-scale Resistance [k ] Resistance [k ] X-Ray Photograph Needle probe measurements GC. Cho

57 Numerical and Experimental Study high conductivity anomaly JY Lee see also Fotti et al.

58 WAVE PROPAGATION

59 Laboratory measurements

60 Penetration depth [cm] TDR Probe Honeycombs Reflection at the probe tip 5 10 Fresh concrete Coarse aggregate (honeycomb) 25 Fresh concrete Time (10-9 sec) Cone in TDR-mode MS Cha

61 Field Devices Typical Data

001 to 10,000 Ohm meter Depth less than 70m

62 Resistivity measurement / imaging Syscal Kid Switch 24 Resistivity range: to 10,000 Ohm meter Depth less than 70m Typical pulse duration: ~0.5s to 2s. (images from

6kHz EM 34 - Ground Conductivity Instrument Shallow (<60 m) Intercoil spacing and operating frequency: 10m at 6.

63 EM devices (conductivity) EM38 Ground Conductivity Instrument Very shallow (~<1m) Conductivity range: 100, 1000mS/m Frequency 14.6kHz EM 34 - Ground Conductivity Instrument Shallow (<60 m) Intercoil spacing and operating frequency: 10m at 6.4kHz, 20m at 1.6kHz, 40m at 0.4kHz Conductivity Ranges 10, 100, 1000 ms/m Geonics (Mississauga): Images from the Terraplus (Colorado) site:

5, 25, 50, 100, and 200 MHz (also borehole)

64 Ground Penetrating Radar (permittivity conductivity and permeability) Pulse EKKO 1000 antenna frequencies; 110, 225, 450, 900, 1200 MHz Pulse EKKO 100 antenna frequencies; 12.5, 25, 50, 100, and 200 MHz (also borehole) Borehole Antennas (50, 100, 200 MHz) Sensors and Software (Mississauga)

65 GPR - 2D & 3D

66 GPR on Ice

67 GPR: Saltwater Intrusion

68 Summary: EM-waves typically non-ferromagnetic caution otherwise (e.g., some mine waste, fly ash) ionic concentration and mobility fresh water: clay surface conduction Simple measurement: ERT, Needle Probe (invasive) free water orientation (microwave frequency) GPR TDR probe (invasive) V V when el and S d S d when el Use volumetric water content consolidation advect./diffus. fluid fronts salt water intrusion freezing fronts hydrates spatial variability buried anomalies

Chapter 4 Influences of Compositional, Structural and Environmental Factors on. Soil EM Properties

Chapter 4 Influences of Compositional, Structural and Environmental Factors on Soil EM Properties 4. 1 Introduction The measured soil electromagnetic properties can be affected by a large number of factors