Undisturbed Soil Sampling on Residual Soil

FYP students worked together with their supervisor to take undisturbed sample of residual soil (so called Kenny Hill formation) at a site near Shah Alam, west of Kuala Lumpur. There was a slight difference in the texture of residual soil at the site only few meters away. One site (A) was very silty without any trace of coarse particles, while the other site (B) shows a slight inclusion of fragmented weathered coarse particles.

Undisturbed samples of 15cm x 15cm x 25cm were successfully taken by using a sort of soil nailing technique for this sampling. A wooden plate 15cm x 15cm was placed at the surface of residual soil ground, and 12 steel bars of 6mm diameter were nailed into the ground at the perimeter of the plate. Then the soil surrounding was excavated by hand shoveling. After the soil block was removed from the ground, the block was reversed in vertical position while attaching the wooden plate and then a thin layer of plaster was applied to secure the soil block from falling apart and drying during the transportation.

In addition to undisturbed samples, disturbed residual soils were taken to carry out further laboratory test, including physical property tests and triaxial strength test on compacted specimen.

The pictures below show the undisturbed sampling at the site.

 excavating undisturbed sample that surrounded by soil nails

 plastering sample for Site B

Views of Site A

Triaxial Test Apparatus Nearly Ready for Standard CD & CU Tests

Pressure supply & control system for triaxial test apparatus has been completed and also calibrations for load cell, LVDT for deformation measurement, and pressure sensor for pore water pressure measurement are completed. Thus FYP students are ready to perform standard triaxial tests on compacted residual soil, although final checking of pressure tube fittings and measurement system needs to be carried out by actually pressurizing and consolidating a soil specimen in the triaxial cell.

At the moment, a data logger which is not connected to computer is used to take all measurements. However, a system of computer controlled measurements and pressure changes using D/P air regulator needs to be introduced to perform more sophisticated triaxial tests such as a cyclic undrained triaxial test.

The picture below shows a control system and loading frame for standard triaxial test that was built solely by FYP student and technical staff of FES laboratory.

Should you be interested in these apparatus, please send your mail to utar.earthquake@gmail.com