Abstract Road base is usually subjected to cyclic traffic loadings as well as environment loads. Evidence shows that excessive permanent deformation of the road base may occur under the action of traffic loads and the complicated suction history induced by climate change. Currently, how the suction history of road base affects its long-term deformation remains unclear. To gain a deep understanding of the long-term deformation of road base, cyclic loading tests were conducted on the road base aggregates (mixture of crushed tuff aggregates and clay fines) under controlled suction and suction histories. A large-size soil-water characteristic curve (SWCC) test apparatus was designed and manufactured for the water retention test of the large-size specimen, and the large-diameter cyclic triaxial testing system (LDCTTS) was upgraded with the unsaturated control system to control the matric suction and suction history during the cyclic loading test. Test results show that the permanent axial strain of the mixture has a negative correlation with the current suction and maximum suction history. The effect of drying-wetting cycles on the permanent axial strain is significant. The permanent axial strain decreases with drying-wetting cycles at the drying path, while increases with drying-wetting cycles at the wetting path. The resilient modulus increases significantly with the current suction magnitude while is independent of the suction history.

中文翻译：

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吸力历史对非饱和路基填料循环行为的影响

摘要 路基通常承受循环交通荷载和环境荷载。有证据表明，在交通荷载和气候变化引起的复杂吸力历史的作用下，路基可能发生过度的永久变形。目前，路基的吸力历史如何影响其长期变形尚不清楚。为了深入了解路基的长期变形，在受控吸力和吸力历史下对路基骨料（碎凝灰岩骨料和粘土细粉的混合物）进行了循环加载试验。为进行大尺寸试件的保水试验，设计制造了大尺寸土水特性曲线（SWCC）测试仪，大直径循环三轴试验系统（LDCTTS）升级为不饱和控制系统，以控制循环加载试验过程中的基质吸力和吸力历史。试验结果表明，混合物的永久轴向应变与当前吸力和最大吸力历史呈负相关。干湿循环对永久轴向应变的影响是显着的。永久轴向应变随着干燥路径的干湿循环而减小，而随着润湿路径的干湿循环而增加。弹性模量随着当前吸力幅度显着增加，而与吸力历史无关。试验结果表明，混合物的永久轴向应变与当前吸力和最大吸力历史呈负相关。干湿循环对永久轴向应变的影响是显着的。永久轴向应变随着干燥路径的干湿循环而减小，而随着润湿路径的干湿循环而增加。弹性模量随着当前的吸力幅度显着增加，而与吸力历史无关。试验结果表明，混合物的永久轴向应变与当前吸力和最大吸力历史呈负相关。干湿循环对永久轴向应变的影响是显着的。永久轴向应变随着干燥路径的干湿循环而减小，而随着润湿路径的干湿循环而增加。弹性模量随着当前的吸力幅度显着增加，而与吸力历史无关。