Evaluation of a machine to determine maximum bulk density of soils using the vibratory method

Abstract

Engineering buildings and other structures such as dams and roadways require soil compaction during construction, so as to limit settling of structures after construction. Optimum water content that results in the maximum soil density is normally desired, so that compaction could be done at this water content. This has to be determined by prior laboratory soil tests usually carried out using the standard Proctor test. The design, construction and testing of a vibratory soil machine, which can produce densities and optimum moisture contents that would mimic the Proctor test is described. A mechanism was designed and developed that vibrated the soil at a given time, amplitude and frequency and resulted in compacting the soil. These factors were varied to determine the ideal parameters for operating the vibratory compactor. Results showed that soil densities increased with increasing sand contents in the soils, increasing amplitude, time and frequency of the machine. Results also showed that the vibratory soil compactor would work best at a frequency of 17 Hz and amplitude of 1.17 mm for five minutes. Soil was compacted in three layers. Further, it worked best in sandy soil producing about 98% of the maximum bulk density from the Proctor test and 97% and 96% for the clay loam and clay soils respectively. The major advantage of the constructed vibratory soil compaction equipment is that it would reduce the tedium involved in the standard Proctor soil compaction test.