Mechanical properties of waste tyre grid reinforced weathered sand based on large triaxial test

Waste tyre grid reinforced coarse granular material can effectively increase the interface bearing capacity, improve durability, avoid construction damage, and has important engineering application value for reinforced roadbed. However, there is a lack of in-depth study on the shear characteristics of waste tyre grid reinforced soil. Therefore, in order to reveal the triaxial shear characteristics of waste tyre grid reinforced weathered sand and determine the parameters of shear strength, taking into account the changes of different confining pressure and different reinforcement rate, a large triaxial indoor test was carried out. The results show that the shear damage pattern of the specimen has a strong correlation with the reinforcement rate and the confining pressure. Compared with the damage pattern of pure sand, the waste tyre reinforced soil did not have a penetrating shear surface, and the middle part of the specimen showed a bulging break. The bulging deformation of the specimen was reduced with the increase of the reinforcement rate and the confining pressure. At the same time, unlike the strain softening characteristics of pure sand, the reinforced specimens showed a strain hardening phenomenon. With or without reinforcement, they showed shear expansion characteristics, and the greater the confining pressure, the more obvious the volume expansion, but the effect of the reinforcement rate is very small. The peak strength and equivalent internal friction angle of the waste tyre grid reinforced soil increased the most with the increase of the reinforcement rate, while the increase of the internal friction angle and shear expansion angle was small.