CRTSⅡ型无砟轨道CA砂浆变形及力学特性动三轴试验研究

CA砂浆是板式无砟轨道的关键组成部分,起弹性垫层的作用。为研究CRTSⅡ型CA砂浆在围压和荷载幅值耦合作用下的变形及疲劳后力学特性,采用GDS三轴仪在5种荷载幅值(0.3,0.35,0.4,0.45,0.5 kN)和4种围压(0,200,400,600 kPa)作用下进行室内动三轴试验,得到累积应变及疲劳后峰值强度的变化规律,并对影响疲劳后峰值强度的荷载幅值和围压进行二元线性回归分析。结果表明:疲劳后的峰值强度随荷载幅值的增加而线性降低,随围压的增加而线性增加;围压增大,荷载幅值对峰值强度的影响减弱,荷载幅值增大,围压对峰值强度的影响作用增强;荷载幅值和围压二元线性回归分析的相关系数为0.973;同一围压下,累积应变随循环次数增加而增加,增长速度渐渐变缓;同一循环次数下,累积应变随荷载幅值的增加而增加,且随着围压增大,荷载幅值对累积应变的影响减弱。

Study on Deformation and Mechanical Properties of CRTSⅡ Ballastless Track CA Mortar under Dynamic Tri-axial Tests

CA mortar is the key part of ballastless slab track and plays the role of elastic cushion.In order to study the deformation and post-fatigue mechanical properties of CRTS Ⅱ CA mortar under the confining pressure and load amplitude,GDS triaxial apparatus is used to conduct indoor dynamic triaxial test under the effect of five load amplitudes(0.3,0.35,0.4,0.45 kN and 0.5 kN) and four kinds of confining pressure(0,200,400 kPa and 600 kPa),and the cumulative strain and peak strength after fatigue are obtained The load amplitude and confining pressure which affect the peak strength after fatigue are conducted with binary linear regression analysis.The result shows that the peak strength after fatigue decreases linearly with the increase of load amplitude and increases linearly with the increase of confining pressure.With the increase of confining pressure,the effect of load amplitude on peak strength becomes weaker,and with the increase of load amplitude,the effect of confining pressure on peak strength increases.The correlation coefficient between load amplitude and confining pressure of binary linear regression analysis is 0.973.Under the same confining pressure,the cumulated strain increases with the increase of the cycle number and the growth rate gradually decreases at the same time.The cumulated strain increases with the increase of the load amplitude in the same cycle times and with the increase of confining pressure,the influence of load amplitude on accumulated strain becomes weaker.