Comparison of Cyclic Triaxial Test Results on Sand-Rubber Tire Shred Mixtures with Dynamic Simple Shear Test Results

摘要

The sand-rubber tire shred mixtures have recently gained the attention of researchers for its potential application as seismic isolation materials. The determination of strain-dependent dynamic properties is crucial for the seismic performance of sand-rubber tire shred mixtures. The cyclic triaxial tests are widely used to find out the dynamic properties of soils due to simplicity. However, it does not simulate the actual stress conditions in the field during an earthquake. The dynamic simple shear tests best simulate the field seismic stress conditions. Therefore, in the present study, the results of dynamic simple shear tests carried out on sand-rubber tire shred mixtures are compared with the results of cyclic triaxial tests. Strain-controlled dynamic simple shear tests were carried out on saturated and isotropically consolidated sand-rubber tire shred mixtures with various gravimetric proportions of sand content (50 to 90%). The samples were subjected to cyclic loading with a frequency of 1.0 Hz. It was found that the shear modulus and damping ratio of sand-rubber tire shred mixtures were highly dependent on shear strain and sand content. The effect of number of loading cycles on the dynamic properties was also investigated. It was also found that the cyclic triaxial tests grossly overestimate the shear moduli but the damping ratios were comparable to those obtained from dynamic simple shear testing.