非饱和橡胶粉土抗剪强度特性研究

Shear strength characteristics of unsaturated rubber silt mixtures

为研究非饱和橡胶粉土的抗剪强度特性,对具有不同橡胶颗粒掺量、含水率的橡胶粉土开展了一系列直剪试验。基于颗粒接触状态理论,构建了橡胶粉土的细观接触模式,建立了基于不同橡胶掺量的橡胶粉土骨架孔隙比计算方法。试验结果表明:在低含水率下,橡胶粉土的抗剪强度随骨架孔隙比增大而减小,在高含水率下,橡胶粉土抗剪强度随骨架孔隙比增大而增大;基于橡胶粉土的土-水特征曲线,得到了基质吸力与含水率的对应关系,在低骨架孔隙比下,橡胶粉土的抗剪强度随着基质吸力的增大而增大,在高骨架孔隙比下,橡胶粉土的抗剪强度随着基质吸力的增大先降低后增大;基于骨架孔隙比及含水率对内摩擦角、黏聚力的影响提出了非饱和橡胶粉土的抗剪强度发展机制,并建立了抗剪强度预测公式。研究结果可为橡胶粉土的实际设计施工提供理论支撑。

To study the shear strength characteristics of unsaturated rubber silt mixtures,a series of direct shear tests was conducted on the rubber silt mixtures with different rubber particle contents and water contents.Based on the particle contact state theory,the meso contact mode of rubber silt mixtures was constructed,and the calculation method of rubber silt mixtures skeleton void ratio based on different rubber content was obtained.The test results show that the shear strength of rubber silt mixtures decreases with the increase of skeleton void ratio at a low water content,while the strength of rubber silt mixtures increases with the increase of skeleton void ratio at a high water content.Based on the soil-water characteristic curve of rubber silt mixtures,the corresponding relationship between matrix suction and water content is obtained.The shear strength of rubber silt mixtures increases with the increase of matrix suction at a low skeleton void ratio,and it exhibits decrease first and then increase with the increase of matrix suction at a high skeleton void ratio.Based on the influence of skeleton void ratio and water content on internal friction angle and cohesion,the shear strength development mechanism of unsaturated rubber silt mixtures was proposed,and the prediction formula of shear strength was established.The research results can provide theoretical support for the actual design and construction of rubber silt mixtures.