Computer-controlled equipment for the direct measurement of the swell potential of expansive soils

Abstract

Expansive soils are found in many parts of the world and are considered as possible disasters to engineering structures. Therefore, early identification of these soils by direct laboratory experiments is extremely important to ensure that the correct design strategy is adopted. Many laboratory procedures have been proposed to measure swell percentage and swell pressure in the literature. One-dimensional consolidation (oedometer) device is commonly used to determine the swell potential of soils. However, this device provides higher values than the reality, and it takes a long time to get the test done. In this study, computer-controlled equipment offering a very ergonomic usage compared to classical consolidation device was developed for direct measurement of swell parameters. Geotechnical properties of forty soil samples taken from different regions of Turkey were identified, and the compaction characteristics of each soil sample were determined by utilizing the standard proctor device at for this purpose. Swell percentage and pressure of these samples were determined by using the developed computer-controlled equipment. Finally, regression equations are developed correspondingly to estimate the swell parameters of the soil samples using the identification and swell test results. It is found that swell potential of the compacted clayey soils can be reasonably well approximated by the use of a regression model consisting of degree of saturation (S) and plasticity index (PI). With these small and easy-to-use devices, both the swell percentage and the swell pressure can be easily monitored at the same time and reported in the desired time interval.