温度梯度作用下板式轨道黏弹性和弹性分析的对比

来源期刊:中南大学学报(自然科学版)2020年第7期

论文作者:高亮 张艳荣 吴楷 蔡小培 严熵

文章页码:2028 - 2039

关键词:温度梯度;黏弹性;垂向应力;垂向位移;层间脱黏

Key words:temperature gradient; viscoelasticity; vertical stress; vertical displacement; interlayer debonding

摘    要:考虑水泥乳化沥青(CA)砂浆层黏弹性,对CA砂浆计算参数进行Prony级数转化,然后通过复合试件试验与有限元建模分析验证引入黏弹性参数的合理性与准确性,进一步分析轨道结构受温度梯度作用产生的垂向应力和位移,同时结合内聚力模型研究层间脱黏发展规律,并与弹性模型的计算结果进行对比。研究结果表明:与弹性模型相比,黏弹性模型的模拟结果与试验结果更为接近;在正负温度梯度作用下,基于黏弹性模型计算的最大垂向应力和最大位移均比弹性模型的大;正温度梯度作用下层间脱黏由板边0.2~0.4 m处萌生并向板边和板中扩展,在负温度梯度作用下,层间脱黏由板边萌生并向板中扩展;与弹性模型相比,黏弹性模型中层间脱黏的贯通温梯较小,最大开口高度和扩展宽度较大且发展更加迅速,说明考虑CA砂浆层黏弹性是必要的。

Abstract: Considering the typically viscoelastic properties of cement emulsified asphalt(CA) mortar, the computational parameters of CA mortar were firstly transformed into Prony series. Then the reasonableness and accuracy of introducing viscoelastic parameters were verified by comparing the measured results of composite specimens with the calculated ones of a viscoelastic finite element model. The vertical stresses and displacements of track structure caused by temperature gradient loading were further analyzed and compared with the calculation results of elastic model. The evolution of interlayer debonding was studied by a cohesive zone model. The results show that the simulation results of viscoelastic model are closer to the experimental values than those of elastic model. Under the action of positive and negative temperature gradient, the maximum vertical stresses and maximum displacements calculated by the viscoelastic model are larger than those by the elastic model. Under positive temperature gradient loading, the interlayer debonding initiates at 0.2-0.4 m away from the edge of the slab, and then extends to the middle and the edge of concrete slab. Under negative temperature gradient loading, the interlayer debonding initiates at the edge of the slab and extends to the middle of concrete slab. Compared with the results of elastic model, the penetration temperature gradient of debonding is lower in the viscoelastic model. The maximum opening height and extension width of debonding present larger values and faster development in the viscoelastic model than those in the elastic model.

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