不同粒径组废旧轮胎橡胶颗粒改良膨胀土性能试验研究

Experimental Study on Expansive Soil Improvement by Waste Tire Rubber Particles of Different Particle Size Groups

为研究废旧轮胎橡胶颗粒粒径与掺量对于膨胀土性能的影响,在击实试验基础上,以0%、5%、10%、15%、20%为掺量,选取4种不同粒径组橡胶颗粒掺入膨胀土进行膨胀率、直剪与无侧限抗压强度试验。试验结果表明:掺入相同掺量、不同粒径橡胶颗粒后的膨胀土,其最大干密度与最优含水率皆随粒径增加而减小;各粒径橡胶颗粒对于膨胀土的膨胀潜势皆有一定的抑制作用,且随粒径、掺量增加,该抑制作用更加明显;掺入粒径较小(<0.25 mm)、粒径较大(>2 mm)橡胶颗粒的膨胀土内摩擦角与黏聚力随掺量波动较为剧烈,橡胶颗粒粒径1~2 mm、掺量10%~15%是提升膨胀土抗剪强度的最佳区间;掺入相同粒径橡胶颗粒的膨胀土,无侧限抗压强度随掺量增加先增加后减小,而相同橡胶颗粒掺量的膨胀土无侧限抗压强度则随粒径增加而增加,且以颗粒粒径2~5 mm、掺量15%为抗压的最佳掺比。

The aim of this research is to investigate the impact of particle size and dosage of waste tire rubber on the mechanical properties of expansive soil.Following compaction tests,expansive soil was mixed with rubber particles of four different size groups,with dosages of 0%,5%,10%,15%,and 20%,for expansion rate test,unconfined compressive strength test,and direct shear test.Test results indicate that the maximum dry density and optimum water content of the improved expansive soil decrease with increasing rubber particle size,despite the same rubber dosage.Rubber particles,regardless of its size,exhibit inhibitory effect on the expansion potential of the expansive soil,with this effect becoming more pronounced as particle size and dosage increase.The internal friction angle and cohesion of expansive soil mixed with rubber particles of small(<0.25 mm)and large(>2 mm)particle sizes fluctuate significantly with varying mixing amounts.The particle size range of 1-2 mm and dosage range of 10%-15%prove most effective in improving the shear strength of expansive soil.The unconfined compressive strength of expansive soil dosed with rubber particles with the same size initially increases and then decreases with increasing dosage.Similarly,the unconfined compressive strength of expansive soil mixed with rubber particles of the same dosage increases with increasing particle size.A particle size of 2-5 mm and a dosage of 15%are determined as the optimal mixing ratio for compression.