Compaction control system for and methods of accurately determining properties of compacted and/or existing ground materials
A compaction control system for and methods of accurately determining properties of compacted and/or existing ground materials. The compaction control system includes a compaction machine that further includes a vibratory drum (or roller). The compaction machine is equipped with sensors to determine position and heading, vibration amplitudes at selected frequencies, and material type and moisture content information. Further, the compaction control system includes a controller and certain algorithms for processing the sensor information. Namely, a method is provided of using the sensor information to assess the improvement in compaction and then determine whether and/or when further ground improvement solutions are needed.
1. An apparatus for providing validated intelligent compaction measurements comprising:
a. a roller compaction machine having a compaction machine drum used to apply dynamic compaction pressure to compacted materials;
b. accelerometers used to measure the dynamic responses of the compacted materials;
c. a positioning device used to determine the x-y-z position of the compaction machine drum;
d. a first algorithm used to determine the real-time dynamic responses (vibration amplitudes at selected sub-harmonic and harmonic frequencies) of the compaction machine drum during compaction;
e. a calibration tool used to calibrate the dynamic response values to independently measured in situ modulus and deformation at selected locations representing clustered regions ranging from the highest to lowest stiffness modulus locations;
f. an output device used to identify x-y-z positions for locations of the compacted materials corresponding to the range of highest to lowest stiffness values; and
g. a second algorithm used to provide validated site-specific stiffness modulus values for the site during compaction.
2. The apparatus of claim 1 , further comprising acceleration sensors selected to provide maximum peak amplitude outputs at the multiples and partial multiples of the harmonic and sub-harmonic frequencies while (a) not exceeding the amplitude range at the fundamental (vibration) frequency and (b) providing a stable sensitivity response up to about 200 Hz.
3. The apparatus of claim 1 , further comprising a photoelectric sensor device used to determine soil moisture content values and soil material type at the x-y-z positions measured during compaction operations.
4. The apparatus of claim 1 , further comprising a visualization output to provide the operator with a real-time measurement of one or more of the following:
a. compacted material stiffness values;
b. material type;
c. moisture content; and
d. layer thickness.
5. The apparatus of claim 1 , further comprising a calibration tool including a penetrometer to measure penetration resistance values at discrete locations.
6. The apparatus of claim 1 , further comprising a calibration tool including an automated plate load test device used to determine the static or dynamic deformation and stiffness values of the compacted materials at discrete locations.
7. The apparatus of claim 6 , wherein the automated plate load test device is performed with or without the addition of confining rings.
8. The apparatus of claim 1 , wherein the second algorithm includes performing multiple linear regression analysis between compactor dynamic responses and independent composite (assumption of homogeneous ground) measurements.
9. The apparatus of claim 8 , wherein the multiple linear regression analyses are performed using the multiple linear regression analysis between compactor dynamic responses and independent layered (determination of layered modulus and thickness values) measurements.
10. The apparatus of claim 1 , further comprising a third algorithm added to determine if the measured compaction stiffness values are in conformance with the project specifications.
11. The apparatus of claim 10 , further comprising a fourth algorithm added to determine if the measured material type values are in conformance with the project specifications.
12. The apparatus of claim 11 , further comprising a fifth algorithm added to determine if the measured moisture content values are in conformance with the project specifications.
13. The apparatus of claim 1 , further comprising a sixth algorithm added to determine the future number of construction passes required to achieve the system requirements.
14. The apparatus of claim 10 , wherein the conformance is provided using a visualized output to the compaction machine operator.
15. An apparatus for providing validated intelligent compaction measurements comprising:
a. a roller compaction machine having a compaction machine drum used to apply dynamic compaction pressure to compacted materials;
b. accelerometers used to measure the dynamic responses of the compacted materials;
c. a positioning device used to determine the x-y-z position of the compaction machine drum;
d. a first algorithm used to determine the real-time dynamic responses (vibration amplitudes at selected sub-harmonic and harmonic frequencies) of the compaction machine drum during compaction;
e. a calibration tool used to calibrate the dynamic response values to independently measured in situ modulus and deformation at selected locations representing clustered regions ranging from the highest to lowest stiffness modulus locations;
f. an output device used to identify x-y-z positions for locations of the compacted materials corresponding to the range of highest to lowest stiffness values;
g. a second algorithm used to provide validated site-specific stiffness modulus values for the site during compaction; and
h. a photoelectric sensor device used to determine soil moisture content values at the x-y-z positions measured during compaction operations.
16. An apparatus for providing validated intelligent compaction measurements comprising:
a. a roller compaction machine having a compaction machine drum used to apply dynamic compaction pressure to compacted materials;
b. accelerometers used to measure the dynamic responses of the compacted materials;
c. a positioning device used to determine the x-y-z position of the compaction machine drum;
d. a first algorithm used to determine the real-time dynamic responses (vibration amplitudes at selected sub-harmonic and harmonic frequencies) of the compaction machine drum during compaction;
e. a calibration tool used to calibrate the dynamic response values to independently measured in situ modulus and deformation at selected locations representing clustered regions ranging from the highest to lowest stiffness modulus locations;
f. an output device used to identify x-y-z positions for locations of the compacted materials corresponding to the range of highest to lowest stiffness values;
g. a second algorithm used to provide validated site-specific stiffness modulus values for the site during compaction; and
h. a photoelectric sensor device used to determine soil material type at the x-y-z positions measured during compaction operations.