TDA与底砟混合物耗能特性试验研究

Test study on energy dissipation characteristics of TDA-subballast mixtures

废旧汽车轮胎颗粒(TDA)加入底砟材料中可以有效减小铁路道床振动与底砟颗粒的磨耗,为探究TDA体积分数对TDA与底砟混合物磨耗性能以及减振耗能特性的影响,确定最优TDA体积分数,对TDA与底砟混合物进行洛杉矶磨耗试验以及大型动三轴试验。研究结果表明:1) TDA的加入能够吸收一定的能量,增加混合物的弹性,进而减小了混合物的洛杉矶磨耗率,添加10%(体积分数)的TDA可使混合物的洛杉矶磨耗率减小约21.5%。2)随着TDA体积分数的增加,混合物的轴向应变和体积应变均呈增大的趋势;混合物的轴向应变随振动次数的发展规律符合对数模型;混合物的回弹模量随着TDA体积分数的上升而下降。3)混合物的耗散能随着TDA体积分数的增加呈增大的变化趋势,TDA体积分数为10%的混合物的耗散能稳定值比纯净底砟的耗散能稳定值提高了约29.5%。满足底砟层变形和刚度要求的最优TDA体积分数为10%左右,此时,TDA与底砟混合物的变形、刚度均能满足要求,颗粒破碎程度显著减小,减振耗能效果显著提高。

The addition of tire derived aggregate(TDA) to subballast can effectively reduce the vibration of the railway track bed and the abrasion of subballast particles.A Los Angeles abrasion test and a large-scale dynamic triaxial test were carried out to study influence of TDA volume fraction on the characteristics of abrasion and energy dissipation of TDA-subballast mixtures and to find the optimal TDA volume fraction.The results show that:1) the addition of TDA can absorb a certain amount of energy and increase the elasticity of the mixtures,and reduce the Los Angeles abrasion value of the mixtures,and when the TDA volume fraction is 10%,the Los Angeles abrasion value of the mixtures decreases by approximate 21.5%.2) With the increase of TDA volume fraction,the axial strain and the accumulative volume strain of the mixtures increase,and the development of axial strain with vibration times accords with the logarithmic model.The resilience modulus of the mixtures decreases with the increase of TDA volume fraction.3) The dissipated energy of the mixtures shows an increasing trend with the increase of the TDA volume fraction,and the stability of dissipated energy for mixture with 10% TDA volume fraction is about 29.5% higher than that of pure subballast.The optimal TDA volume fraction that meets the deformation and stiffness requirements of bottom ballasted layer is about 10%.Under the optimal condition,the deformation and stiffness of the TDA-subballast mixtures both can meet the requirements,the particle breakage is significantly reduced,and the effect of energy consumption is significantly improved.