ABSTRACT

This study explores the development law of concrete internal stress and strain under rolling wheel loads. To do this, strain gauges are embedded in different positions inside concrete, and the stress and strain values at different positions inside the concrete are measured using the rolling fatigue test. A numerical model is established using COMSOL Multiphysics software, and the concrete internal stress and strain values are simulated. A comparison between the calculated and measured values shows that the numerical model can simulate the actual stress state inside the concrete. The numerical model can predict the internal stress and strain variation of concrete specimens under more complicated load conditions. The prediction results show that under the same fatigue load conditions, the concrete stress peak is hardly affected by the fatigue loading times, but there is a marked increase in the strain value inside the specimen. When the stress peak of concrete does not reach its design strength, an excessive increase of the internal strain will cause hidden damage to the concrete. By investigating the internal stress and strain of the concrete, a theoretical basis can be determined for the deterioration mechanism of concrete microstructure and the durability design of concrete.

摘要

本研究探讨了滚动车轮荷载作用下混凝土内应力和应变的发展规律。为此，应变仪嵌入混凝土内部的不同位置，并使用滚动疲劳试验测量混凝土内部不同位置的应力和应变值。使用 COMSOL Multiphysics 软件建立数值模型，并对混凝土内部应力和应变值进行模拟。计算值与实测值的比较表明，数值模型可以模拟混凝土内部的实际应力状态。该数值模型可以预测更复杂荷载条件下混凝土试件的内应力和应变变化。预测结果表明，在相同的疲劳载荷条件下，混凝土应力峰值几乎不受疲劳加载时间的影响，但试样内部的应变值明显增加。当混凝土的应力峰值没有达到其设计强度时，内应变的过度增加会对混凝土造成隐患。通过研究混凝土的内应力和应变，可为混凝土微观结构的劣化机理和混凝土的耐久性设计提供理论依据。