高速铁路基床掺胶粉水泥稳定碎石动力学特性分析

Dynamic Characteristics Analysis of Cement Stabilized Crushed Stone Mixed with Rubber Powder for High-speed Railway Bed

为明确掺胶粉水泥稳定碎石在高铁列车循环荷载作用下的力学变形特征和能量损耗规律,将胶粉以等体积方式部分替换掉原集料中1.7 mm以下的细颗粒,形成胶粉改性水泥稳定碎石材料。通过对300 mm×300 mm圆柱形试样进行105次的循环加载试验,在5 Hz加载频率下研究了不同动应力幅值、胶粉掺量对试样动力学变形及能量耗散的影响规律,给出了基于实际服役水平状态下胶粉改性水泥稳定碎石的累积塑性变形计算模型和阻尼比的演化规律。试验结果表明:从变形角度,C_(5)P_(0.1)R_(30)材料的累积塑性变形最小,表现出较好的抗动力学变形特征;橡胶粉的掺入增加了水泥稳定碎石材料的韧性,降低了应力幅值增加对累积塑性变形增加的敏感性;结合累积塑性变形计算模型,并从参数分析的角度看,C_(5)P_(0.1)R_(30)可作为基床表层结构推荐材料;从阻尼比角度看,胶粉替换水平为30%时,阻尼比数值较大,路基结构受高铁列车动荷载激振后,能量衰减较快,具备一定的减振降噪潜力。因此,基于对胶粉改性水泥稳定碎石动力学特性分析,推荐1.7 mm以下胶粉等体积替换水平为30%,这对于改善高铁路基基床表层材料刚度,构建减震降噪型路基结构具有重要意义。

In order to clarify the mechanical deformation characteristics and energy loss law of cement stabilized gravel doped with micaceous powder under the cyclic loading of high-speed trains,the fine particles below 1.7 mm in the original aggregate were partially replaced by rubber powder in an equal volume manner to form a rubber powder modified cement stabilized macadam material.The effect of different dynamic stress amplitude and dosing amount of rubber powder on the kinetic deformation and energy dissipation of the specimens was studied by cyclic loading test of 300 mm×300 mm cylindrical specimens for 105 times at 5 Hz loading frequency,and the calculation model of cumulative plastic deformation and the evolution law of damping ratio of rubber powder modified cement stabilized macadam based on the actual service level condition was given.The test results show that from the perspective of deformation,the cumulative plastic deformation of C_(5)P_(0.1)R_(30)material is the smallest and shows better characteristics of resistance to kinetic deformation.The incorporation of rubber powder increases the toughness of cement stabilized macadam material and reduces the sensitivity of increasing stress amplitude to the increase of cumulative plastic deformation.Combined with the cumulative plastic deformation calculation model and from the perspective of parametric analysis,C_(5)P_(0.1)R_(30)can be used as the recommended material for the bed surface structure.From the perspective of damping ratio,when the replacement level of rubber powder is 30%,the value of damping ratio is larger,and the roadbed structure is subjected to dynamic load excitation of high-speed trains,the energy attenuation is faster and has certain potential for vibration and noise reduction.Therefore,based on the analysis of the kinetic characteristics of the mastic powder modified cement stabilized gravel,it is recommended that the equivalent volume replacement level of rubber powder below 1.7 mm is 30%,which is of great significance to improve the stiffness of the surface layer material of the high-speed railway roadbed and build a vibration and noise reduction roadbed structure.