Humboldt H-4140 GeoGauge - Manual (Page 15)

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7.0: Sequence Of Operations For A GeoGauge
Stiffness/Modulus Measurement
Making Stiffness Measurements With The GeoGauge Per The Following
Procedure Conforms To ASTM D6758
• Inspect The Condition Of The GeoGauge Prior To Testing
1) Is the foot clean and free of soil and other debris?
2) Is the rubber seal in good condition?
• Turn On The GeoGauge (press “ON” button)
1) The self-test will be run (electronics functionality).
2) Ensure battery voltage is adequate (> 7.5 V).
3) No warm-up required before measurements.
• Prepare The Surface To Be Tested (see Site Preparation)
1) Is the surface smooth and level?
2) Coarse aggregate, hard surfaces or stiff clay may require moist
sand to be patted on the surface for good direct contact with
the foot.
3) Ensure the gauge has clearance on the side and bottom, does not
come into contact with a trench wall, pipe, soil, etc.
• Enter Data
Enter target stiffness from pre-defined, scrolled list via display,
if necessary.
• Verify GeoGauge Operation (daily)
Perform a check of GeoGauge operation per the GeoGauge Verifier
Mass Guide (see Appendix 4). The GeoGauge is operating properly
if the mean stiffness is within approximately -8.6 MN/m and -9.8 MN/m.
• Establish GeoGauge Precision (daily)
Locate some compacted material that is representative of what is to
be measured that test day. Make a minimum of 3 measurements at
the same test location. GeoGauge precision is sufficient if the
coefficient of variation of the measurements is less than 10%.
• Seating Of The Foot
How to properly seat the foot will be determined by on-site trial per
the recommendations above (see GeoGauge Seating).
• Take The Measurement (press “Meas” button)
1) GeoGauge will measure noise as a function of frequency.
2) GeoGauge will measure stiffness as a function of frequency.