为提高废旧轮胎利用率,可将其加工成不规则形状的破碎料,并与土体混合而成TDA混合土,具有减轻土体自重、提高土体抗剪强度等特性,近年来被尝试用作桥台、挡土墙等结构物的台背回填材料。为揭示TDA混合土剪切特性与细观机理,首先基于自...为提高废旧轮胎利用率,可将其加工成不规则形状的破碎料,并与土体混合而成TDA混合土,具有减轻土体自重、提高土体抗剪强度等特性,近年来被尝试用作桥台、挡土墙等结构物的台背回填材料。为揭示TDA混合土剪切特性与细观机理,首先基于自制大尺寸直剪仪测定混合土抗剪强度,并据此建立了DEM计算模型,开展了TDA混合土受剪过程中的细观力学分析。结果表明,TDA掺入比为0~15%范围内,抗剪强度随掺入比的增加而增加,其力学机理主要表现为不规则轮胎颗粒可有效调动土颗粒的抗剪能力,形成斜向贯穿的强力链连接的剪切带区域,颗粒间的总接触力、法向接触力均明显增大,接触力角度集中于斜向45˚附近区域,验证了TDA掺入对混合材料剪切强度的提高作用。In order to improve the utilization rate of waste tires, they could be processed into irregularly shaped crushed materials and mixed with soil to make TDA mixed soil, which had the characteristics of reducing the self-weight of the soil and improving the shear strength of the soil, and had been tried to be used as backfill material for bridge abutments, retaining walls and other structures in recent years. In order to reveal the shear characteristics and fine-scale mechanism of TDA mixed soil, firstly, the shear strength of mixed soil was measured based on a homemade large-size direct shear instrument, and a DEM calculation model was established accordingly to carry out the fine-scale mechanical analysis of TDA mixed soil in the process of shear. The results showed that the shear strength increased with the increase of TDA incorporation ratio in the range of 0~15%, and the mechanical mechanism mainly showed that irregular tire particles could effectively mobilize the shear capacity of soil particles and form a shear zone region connected by strong chains running diagonally. The total contact force and normal contact force between the particles were significantly increased, and the contact force angle was concentrated in the area near 45˚ in the oblique direction, which verified the improvement effect of TDA incorporation on the shear strength of the mixed material.展开更多
文摘为提高废旧轮胎利用率,可将其加工成不规则形状的破碎料,并与土体混合而成TDA混合土,具有减轻土体自重、提高土体抗剪强度等特性,近年来被尝试用作桥台、挡土墙等结构物的台背回填材料。为揭示TDA混合土剪切特性与细观机理,首先基于自制大尺寸直剪仪测定混合土抗剪强度,并据此建立了DEM计算模型,开展了TDA混合土受剪过程中的细观力学分析。结果表明,TDA掺入比为0~15%范围内,抗剪强度随掺入比的增加而增加,其力学机理主要表现为不规则轮胎颗粒可有效调动土颗粒的抗剪能力,形成斜向贯穿的强力链连接的剪切带区域,颗粒间的总接触力、法向接触力均明显增大,接触力角度集中于斜向45˚附近区域,验证了TDA掺入对混合材料剪切强度的提高作用。In order to improve the utilization rate of waste tires, they could be processed into irregularly shaped crushed materials and mixed with soil to make TDA mixed soil, which had the characteristics of reducing the self-weight of the soil and improving the shear strength of the soil, and had been tried to be used as backfill material for bridge abutments, retaining walls and other structures in recent years. In order to reveal the shear characteristics and fine-scale mechanism of TDA mixed soil, firstly, the shear strength of mixed soil was measured based on a homemade large-size direct shear instrument, and a DEM calculation model was established accordingly to carry out the fine-scale mechanical analysis of TDA mixed soil in the process of shear. The results showed that the shear strength increased with the increase of TDA incorporation ratio in the range of 0~15%, and the mechanical mechanism mainly showed that irregular tire particles could effectively mobilize the shear capacity of soil particles and form a shear zone region connected by strong chains running diagonally. The total contact force and normal contact force between the particles were significantly increased, and the contact force angle was concentrated in the area near 45˚ in the oblique direction, which verified the improvement effect of TDA incorporation on the shear strength of the mixed material.
