Permeability of compacted soils

• Main Author: Kek, Hardy Yide
• Other Authors: Leong Eng Choon
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/61141
• Institution: Nanyang Technological University

More than two-thirds of Singapore’s land area are covered with residual soils. Residual soils are often compacted and used for engineering construction works due to its favourable engineering properties. Compacted soils are by nature unsaturated. Unlike saturated soils, permeability of unsaturated soils is a function of void ratio and degree of saturation. The objectives of this project were to investigate the effects on soil fabric on permeability and to evaluate the direct and indirect methods used to measure permeability. In this project, both saturated and unsaturated coefficients of permeability of compacted residual soils were measured at the same relative compaction on the standard and modified Proctor compaction curves. A flexible-wall permeameter was used to measure the saturated and unsaturated coefficients of permeability of the soil specimens directly while the minidisk infiltrometer and a permeability function (ACUPIM/W) based on the drying soil-water characteristic curve were used for the indirect methods. Differences in the saturated and unsaturated coefficients of permeability were observed for the specimens at the dry and wet of optimum of the compaction curves. However, the differences in permeability could not be attributed solely to the soil fabric due to differences in the specimen void ratios after saturation. Measured coefficients of permeability obtained from the flexible-wall permeameter and mini disk infiltrometer were consistent with values obtained from ACUPIM/W. Suggestions for further improvement of the flexible-wall permeameter are also included in this report.