Development of Soil Stiffness Evaluation Equipment “Alfa-System” Using Acceleration Response of Vibratory Roller

Recent years, new construction systems as AMG (automatic Machine Guidance) and AMC (Automatic Machine Control) have been developed with the Global Positioning System (GPS) and made fit for practical use. Added to this, an indirect measuring theory to control the compaction extent and elasticity, which uses the acceleration data of compaction drum, has been researched and developed since 1998 in Japan, and has recently come to be applied to the real construction sites. From such a background, the authors developed new equipment which is named “Alfa-system” for quality control of soil compaction. The advantage of the system is as follows. Fill compaction levels can be real-timely judged. Acceleration data of wheel vibration are consecutively measured, and these data are transmitted to the control room for data processing. Then, the data are compared with the standard control values that are established beforehand by the test executions. Examined data can be used for countermeasures, such as eliminating the under-compacted or inferior parts. And this system provides more benefit, once using system in construction, both supervisor in the sight office and driver of the compaction rollers can see 2-dimentional pictures of the compacted levels on the computer screens. And the data from Alfa- system can be used for QC/QA. Moreover, in the future, the system can be improved to feed back to the quality control immediately. This will improve the effectiveness and efficiency of compaction control.