Field In-Situ Density Test versus Lab Compaction Test

This week, five FYP students with their supervisor have carried out field in-situ density test at the same site (Site A & B) as previously reported. This was to examine the field dry density of residual soil, while the laboratory compaction tests on these two soils have been carried out at UTAR Civil Eng. laboratory. A water filled balloon (plastic bag) was used to measure the volume of soil that was dugout from the ground, and the soil dugout from a hole (approximately 12cm dia x 10-15cm deep) was carefully collected for weight and water content measurements at laboratory as shown in photos.

A comparison between field dry densities and laboratory proctor compaction test results are shown in the figure. Based on these results, the field dry densities at Site A and Site B can be defined as approximately 1.6 tf/m3 and 1.5 tf/m3 respectively. The rain fall in the previous day of site investigation has made the ground fairy wet, so that the water contents were high at these site, ranging from 18 to 22%. One of field data (first trial test of in-situ density tests) from Site B shows a value above the zero air void curve and therefore this should be disregarded.

FYP students will carry out a series of triaxial test to study the deformation properties of residual soil in small strain range by using both undisturbed and compacted samples. Also shaking table test and hollow cylinder test are planned to study the deformation properties of residual soil in small strain range by using compacted sample.

For further information on FYP studies, please contact us at utar.earthquake@gmail.com.

Comparison of field density test data with laboratory compaction curves

Shaking Table Started to Operate

This week, the operation of shaking table has started successfully. The shaking table is operated by sending a digital command to the controller of mega-torque motor. Both regular and irregular shaking is possible by using a program on laptop computer written in Visual Basic. This program is written by Dr. Lohani of GEO. institute of Japan. Because some response limitation of the mega-torque motor, the shaking is possible within a limit that is combination of frequency and shaking displacement.

The next task of FYP team is to find out these limits and calibrate the shaking intensities that can be applied by this apparatus. As these apparatus have been assembled entirely by the technical staff of UTA (FES/Civil), the maintenance and further developments of such apparatus would be possible.

If there is any interest on this apparatus, please write to utar.earthquake@gmail.com