Intelligent Soil Compaction Systems (2010) / Chapter Skim
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Fundamentals of Roller Measurement Values The reader is referred to Facas & Mooney (2010) for a thorough description of roller MV reporting.
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Figure 3.1. Sample roller MV data records for (a)
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0 the drum length [2.1 m (6.9 ft) for the rollers used here]
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Mooney 2010)
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table 3.3. observed position reporting errors for roller MVs.
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verify the proper working condition of a roller measurement system and should be considered when interpreting pass-topass changes in MVs commonly used in CCC specifications (see Sections 7.5.3 and 7.7.2)
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The repeatability tests described here provide useful insight into the limitations of roller MV data in QA specifications, particularly the spatial comparison of pass-to-pass roller MV. As described in Section 2.3.2, one Austrian and ISSMGE specification approach for roller-integrated CCC examines the pass-to-pass change in mean MV (averaged over the evaluation section)
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in the tracks of the two rollers and differences in reporting methods. The Case/Ammann k s value was compared with the k s-CSM determined from the Sakai roller vibration data (see Figure 3.12a)
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Figure 3.14. Comparison of Case/Ammann ks , Dynapac CMVD , and Sakai CCV data on granular soil (TB FL18)
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mately 10, underscoring the findings in the literature (see Chapter 2)
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(%ΔMV) in Figures 3.17b and c]
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Figure 3.21. Influence of roller speed on Sakai CCV (f = 20 Hz)
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0 3.6 Influence of Transverse Soil Heterogeneity on Roller Measurement Values Soil density, moisture, and stiffness vary locally. A review of the roller MV records presented in this chapter illustrates that soil properties vary, sometimes considerably, within a length scale of tenths of a meter (one-third of a foot)
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3.7 Conclusions and Recommendations The following conclusions can be drawn from the results presented in this chapter: • Each vibration-based roller MV investigated -- Ammann and Case/Ammann k s , Bomag E vib , Dynapac CMV D , and Sakai CCV -- is a reflection of soil stiffness over a spatial distance that varies across MVs [0.06 to 1.0 m (0.2 to 3.3 ft) observed]
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sequences, there is considerable benefit to using roller MVs in both forward and reverse modes. Forward and reverse mode measurement should be considered; however, sitespecific calibration is required to characterize and verify the relationship between forward-measuring and reversemeasuring roller MVs.
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