加载速率对沥青混凝土力学性能影响的三轴试验研究

Triaxial experimental study of effect of loading rate on mechanical properties of asphalt concrete

摘要

为研究加载速率因素对沥青混凝土试样力学性能的影响规律，选择4种加载速率进行了沥青混凝土静三轴试验。结果表明，加载速率对沥青混凝土力学性能有较为显著的影响，试验应力应变曲线随加载速率、围压呈现一定规律性变化。在相同试验温度和围压条件下，偏应力随着加载速率的增大而增大。在不同围压的低速段条件下，加载速率的变化对沥青混凝土最大偏应力的影响较为明显。在相同加载速率和温度条件下，偏应力随着围压的增大而增大，最大偏应力值也随着围压的增大而逐渐增大，并且基本呈现出线性关系。加载速率对邓肯张模型参数也有显著的影响，随着加载速率的增大，模型参数k、n和黏聚力c呈增长趋势，内摩擦角φ随着加载速率的增大呈减小趋势，并逐渐趋于稳定。对比邓肯张模型参数计算曲线和试验曲线，说明邓肯张模型不能反映材料应变软化特征。

Abstract

In order to study the influence of loading rate on the mechanical properties of asphalt concrete, Static triaxial tests of asphalt concrete are conducted under four different loading rates. The results show that loading rate has a significant effect on the mechanical properties of asphalt concrete and the stress-strain curve changes regularly with the loading rate and confining pressure. Under the same test temperature and confining pressure conditions, the deviator stress increases with the increase of loading rate, and the change of loading rate has obvious influence on the maximum deviator stress of asphalt concrete under different confining pressure conditions. Under the same loading rate and temperature conditions, the deviator stress increases with the increase of confining pressure, and the maximum deviator stress also increases gradually with the increase of confining pressure, and basically presents a linear relationship. The loading rate has significant influence on the parameters of model concluded by Duncan-Chang Model. With the loading rate increases, model parameters k, n and cohesion force c increase, while the internal friction Angle φ decreases with the loading rate increasing and gradually becomes stable. The comparison between the parameter calculation curve and the test curve shows that the Duncan tensor model cannot reflect the strain softening characteristics of the material.

关键词

沥青混凝土 / 静三轴试验 / 应力应变曲线 / 邓肯张模型

Key words

asphalt concrete / static triaxial tests / stress-strain curve / Duncan-Chang model