聚氨酯发泡材料以其快速膨胀、高强、轻质及憎水等特点，在水毁道路等的临时抢通中有着重要的工程价值。为了研究车辆循环荷载作用下换填临时路基的聚氨酯材料力学性能，分别对聚氨酯试样进行轴向循环加卸载压缩试验及切向循环剪切试验，分析了聚氨酯试样在不同加载频率和加载范围下的应力-应变变化规律及宏细观破坏特征。结果表明：聚氨酯试样的应变随轴向加载频率先增后减，随轴向应力加载上限值持续增大（可达到7%~8%）；轴向应力加载引起的最大应变增量是加载频率相应值的4倍，对试样应变的影响更为显著；切向循环加卸载下，试样主要以沿胶结面的压剪破坏和沿竖向裂隙-胶结面处的拉剪破坏为主，切向力加载范围的增大会引起试样变形的明显增加（最大应变达5%~6%），最终出现沿胶结面的压剪破坏；增加一定的轴向力（不宜超过单轴抗压强度的90%）能更好压实聚氨酯材料，进而能改善其抗剪性能，在工程应用中，应当尽量避免轴向（法向）力较小或无加载时让聚氨酯材料处于循环剪切受力状态。

Polyurethane foam material, with its rapid expansion, high strength, lightweight, and water-repellent characteristics, has significant engineering value in temporary repair works such as emergency road clearance after water damage. To study the mechanical characteristics of polyurethane materials for subgrade under cyclic loading, axial cyclic loading and unloading compression test , and tangential cyclic shear test were carried out on polyurethane samples containing interface, and the change rule of stress-strain law and macro and micro damage characteristics of polyurethane samples wereanalyzed under different loading frequencies and loading ranges. The results show that: The strain of polyurethane samples increases and then decreases with the frequency of axial loading, and continuously increases with the upper limit of axial stress loading (up to 7%~8%); the maximum strain increment induced by axial stress loading is four times the corresponding value for the loading frequency, which has a more significant effect on the sample strain; under axial cyclic loading and unloading, the sample is mainly subjected to compression-shear damage along the cemented surface and tensile-shear damage along the vertical fissure-cohesive surface, the increase in the loading range of the tangential force causes a significant increase in the deformation of sample (up to 5%~6%), and eventually compression-shear damage along the cemented surface occurs; increase a certain amount of axial force (should not exceed 90% of the uniaxial compressive strength) can be better compaction of polyurethane materials, which can improve its shear performance, in engineering applications, it is advisable to avoid placing polyurethane materials in a cyclic shear stress state when the axial force is small or there is no loading.

U414

湖北省交通运输厅科技项目(20221164)