摘要
为揭示橡胶–砂颗粒混合物强度特性变化规律和微观结构特征,通过室内直剪试验、无侧限抗压强度试验和扫描电镜试验,研究橡胶掺量、竖向应力和养护龄期等对颗粒混合物抗剪强度、内摩擦角、应力–应变关系和抗压强度的影响,同时定性评价颗粒混合物微观结构的变化,探讨橡胶–砂颗粒混合物相互作用的微观机制。结果表明:橡胶–砂颗粒混合物密度随橡胶掺量增加而线性减小;橡胶颗粒的添加会降低颗粒混合物的抗剪强度和抗压强度,内摩擦角与橡胶掺量呈线性减小关系;橡胶–砂颗粒混合物的应力–应变特征随橡胶掺量增加表现出由"脆性"向"韧性"转变的趋势;低橡胶掺量的颗粒混合物受荷介质主要是砂颗粒组成的受力链,橡胶颗粒可有效阻止砂颗粒的滑移和倾覆,高橡胶掺量的颗粒混合物主要依靠橡胶颗粒的大变形承担荷载。
To illustrate the variation laws of strength characteristics and micromechanism of rubber-sand mixtures, a series of laboratory tests including direct shear tests, unconfined compressive strength tests and scanning electron microscopy analysis are conducted to study the effects of rubber fraction, vertical stress and curing time on the shear strength, internal friction angle, stress-strain characteristics and unconfined compression strength of sand-rubber mixtures. Moreover, the variations of microstructure of rubber-sand mixtures are qualitatively evaluated, and the micromechanisms of the mixtures are also discussed. The experimental results show that the density of rubber-sand mixtures decreases linearly with the increase in rubber fraction. Addition of rubber chip can reduce the shear strength and unconfined compression strength of mixtures. The relationship between internal friction angle and rubber fraction is linear. The stress-strain characteristics of rubber-sand mixtures exhibit a tendency to change from ＂brittle＂ to ＂ductile＂ with the increase in rubber fraction. Some force chains are generated to support the external loading when the rubber fraction is low. Rubber chips often play an important role in preventing the slipping and buckling of sand particles. The rubber-sand mixtures with high robber fraction mainly rely on the large deformation of rubber chips to support the loading.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2017年第6期1082-1088,共7页
Chinese Journal of Geotechnical Engineering
基金
国家自然科学基金项目(41672294)
国家重点研发计划课题(2016YFC0800201)
中央高校基本科研业务费专项资金项目(CUG170636
CUGL170807)
关键词
废弃轮胎
橡胶颗粒
强度
应力-应变特征
微观机制
scrap tire
rubber chip
strength
stress-strain characteristic
micromechanism
