Evaluating the Effect of Fiber Content on the Shear wave Velocity and Small-strain Shear Modulus of Municipal Solid Waste Using Bender Element (BE)

During the past years researchers have conducted a number of comprehensive in-situ and laboratory tests on municipal solid waste (MSW). Following these investigations, for the purpose of measuring shear wave velocity and small-strain shear modulus a set of bender element device mounted on cyclic triaxial test apparatus located in Iran University of science and technology was employed. Tests were conducted on medium-sized samples of fresh MSW in order to primarily evaluate the influence of fiber content (fiber contents of 0, 3 & 6 %), confining stress (75, 150 & 300 kPa confining stress) and unit weight (9 & 12 kN/m3) on shear wave velocity and small-strain shear modulus. The influence of fiber content on movement of shear wave velocity was observed using bender element tests. Although increasing the fiber content of MSW samples caused a higher shear wave velocity, the energy of received wave by bender element device had lower magnitude this could be attributed to lower capacity of plastic fibers to transmit the wave, however the increased shear wave velocity of samples with greater fiber content could be attributed to higher compaction effort. It is considerable that the effect of fiber content is more significant under higher confining stress.