Plate Bearing Test Anix AX01 Research Papers
|Relationship between surged reaction modulus and the strain modulus obtained using a plate loading test – High Speed Rail – Dae Sang Kim (Korea Railroad Research Institute) & Seong Yong Park (Hanwha Research Institute of Technology) – 2011
Plate loading tests (PLTs) have been used to evaluate the compaction quality of the railroad subgrade in Korea. Two methods to determine the design modulus are being used together; one is an unrepetitive plate loading test (uPLT) that obtains the subgrade reaction modulus (K30) and the other is a repetitive plate loading test (rPLT) (e.g. Anix AX01a) that obtains the strain modulus (Ev). There are some differences between the two methods, such as, the way in which the design modulus is evaluated, the number of loading steps, and the test procedures. Firstly, this paper compares the two test methods and summarizes the differences between them. Secondly, the relationship between the two moduli was obtained by using the results of 30 field tests of uPLT test and rPLT test carried out on the subgrade under railroad construction. The comparisons show that the two tests give large differences in stress-displacement relationship and that the correlations between the two moduli didn’t indicate a good relationship. Consequently, it was found that corrections of two the moduli for stress and strain level are needed to evaluate the relationship between the two moduli, because the stress and strain level are different when K30 and Ev2 are evaluated. Therefore, if the relationship between the two moduli is developed from the correction procedure, it will help field engineers in the management of compaction control for railway embankments.
Comparative Studies between the Plate Load Test (PLT) and other Devices
Best practice in compaction quality assurance for pavement and subgrade materials – National Asset Centre of Excellence (NACOE) – Queensland Department of Transport and Main Roads and the Australian Road Research Board (ARRB) – P60
The acceptance of earthwork and unbound pavement construction in Australia currently relies mostly on density testing and CBRs for Quality Assurance (QA).
Though its National Asset Centre of Excellence (NACoE) research program, Queensland’s Department of Transport & Main Roads sponsored a vital ARRB research project to update test methods acceptable for use for QA of pavement and subgrade materials. This state-of-the-industry study assessed test methods that have the potential to:
(a) reliably provide a direct measure of the strength or in-situ modulus value; and
(b) offer significant time savings in turnaround time of test results.
Methods evaluated included Light Weight Deflectometer’s (LWD’s), PANDA® Instrumented DCP, Clegg Hammer, DCP and Plate Load Testing (PLT). Specifically, the devices evaluated included the Zorn Light Weight Deflectometer, the Anix Instrumented Plate Load Test and PANDA® Instrumented DCP.
In earthworks testing, using density ratios is applied widely in quality control. There are currently many different measuring devices which can provide a more accurate measurement of design parameters (strength or stiffness) and can provide a more direct route for parameter assessment (i.e. limit need for any inclusion of generic relationships).
Comparisons of density with alternative in-situ testing show the latter provides significant benefits to the industry. Accuracy is not the same as precision, and industry’s reliance on density places an emphasis on precision rather than accuracy, data usability or timeliness of results.
This research has found density measurements are, although precise, not very accurate due to poor correlation with the results of other modulus or strength-based tests.
- Dr Jeffrey Lee – ARRB
- Dr Burt Look – FSG – Geotechnics + Foundations
- Dr David Lacey – FSG – Geotechnics + Foundations
Part 1: June 2018
Part 1 introduced alternative methods to assess compaction in the field. The advantages, limitations, and fundamentals of the measurement methods are discussed.
Part 2: February 2020
Part 2 compared the limitations, benefits and issues associated with traditional density testing and other types of testing with research data various sites.
Part 3: March 2020
Part 3 focused on the applications and procedures associated with alternative testing to a density-based approach.
|Best Practice in Compaction QA for Pavement and Subgrade Materials NACOE P60 Year 3 Report Lee, Lacey, Look & Tarr June 2020|