Abstract
This paper investigates the possible application of recycled tyre shreds as compressible inclusion behind retaining walls under dynamic loading. It is a novel method to reduce the magnitude of earthquake-induced dynamic forces against rigid earth retaining wall structures. A numerical model to analyze the behavior of retaining walls with compressible cushion was developed in PLAXIS 2D, a two-dimensional finite element analysis based software, and the results were validated by comparison with experimental findings from physical models. The study evaluates the effects of thickness of compressible cushion and the friction angle of the backfill on the seismic performance of retaining walls. To assess the effect of frequency on wall performance with and without cushion, the wall was subjected to 15 cycles of sinusoidal excitation with acceleration amplitudes of 0.1g to 0.3g at a frequency of 7 Hz. The results from the numerical analysis indicate that the permanent displacements of the wall were reduced in the range of 38% to 52% and the horizontal earth pressures were reduced by about 55% to 76% due to the presence of tyre shreds as a compressible cushion between the wall and backfill. Results showed that the dynamic load against the retaining wall can be considerably reduced through the proposed technique. Doi: 10.28991/cej-2020-03091631 Full Text: PDF
Highlights
Earth retaining structures represent an essential component of many civil engineering works
They reported friction angle as high as 67° for sand reinforced by tyre shreds, while friction angle of sand alone was found to be 34°.Tweedie et al [12] found that using tire shreds as a backfill material resulted in low earth pressures on the retaining wall, which allowed a decrease in the wall thickness
The results presented above indicate that recycled tyre shreds acted well as compressible inclusions in reducing permanent displacements and horizontal earth pressures on the wall, of the three various thicknesses, considered the lowering is larger in the thicker compressible layer due to the lightweight and compressible nature of the tyre shreds
Summary
Earth retaining structures represent an essential component of many civil engineering works. Foose et al [11] investigated the use of shredded waste tyres to reinforce sand, performed direct shear tests on tyre shred-sand mixtures They reported that shear strength was considerably impacted by the normal stress, the content of tyre shreds, and unit weight of the sand matrix. They reported friction angle as high as 67° for sand reinforced by tyre shreds, while friction angle of sand alone was found to be 34°.Tweedie et al [12] found that using tire shreds as a backfill material resulted in low earth pressures on the retaining wall, which allowed a decrease in the wall thickness. The seismic efficiency of retaining walls constructed with Tyre Derived Aggregate (TDA) was evaluated recently by Xiao et al [13] and reported that wall displacements, accelerations, and dynamic backfill stresses were reduced noticeably by the use of TDA compared to those of conventional sand backfill
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