Impact of shell content on compressibility of granular material for land reclamation

In Singapore, sand used for land reclamation contains a variable amount of shell content. The amount of shell content will affect the engineering properties of the sand. As the compressive strength of the shell content is much lower than silica sand, a high shell content may adversely affect the densification and compressibility of the granular material. This will lead to settlement problems in the reclaimed land. The objectives of the project are to evaluate methods used to determine the carbonate content in sand containing shells and to study the impact of various amounts of shell content and relative density on compressibility of reclamation sand. Carbonate content tests in accordance to BS1377 and BS6463 were conducted to determine the amount of calcium carbonate present in the sand. To investigate the compressibility of the sand, oedometer tests were conducted on sand from three different sources at different relative densities and at various shell contents. Constant rate of strain (CRS) tests were conducted too. Results from the study shows that carbonate content tests by BS1377 and BS6463 are comparable. The test results are consistent with those obtained by SANS5840. A decrease in relative density leads to an increase in Cc . An increase in shell content also leads to an increase in Cc . However, the effect of relative density on Cc is less than the effect of shell content on Cc . As the percentage of shell increases, both Cc and Cr values increases. However, Cc values experience a greater increase than Cr . The effect of shell content on Cc is small when shell content is less than 20 percent.Bachelor of Engineering (Civil