Tan Bo, Yang Tao, Qin Heying, Liu Qi
College of Civil and Architecture Engineering, Guilin University of Technology, Guilin 541004, China.
Guangxi Key Laboratory of New Energy and Building Energy Saving, Guilin 541004, China.
Materials (Basel). 2021 Mar 24;14(7):1584. doi: 10.3390/ma14071584.
In this paper, the stability of large-size graded crushed stone used for road base or cushioning under repeated load is investigated. Using an in-house developed device, large-size crushed stone mix was compacted and molded by the vibration and rotary compaction method. Cyclic rotating axial compression was applied, and the shakedown theory was used to study the cumulative deformation of the large-size crushed stone specimens. The effects of gradation parameters on the cumulative strain and stability behavior were analyzed, and the critical stability and failure loads were determined according to the shakedown theory. The test results indicate that there are three obvious instability behavior stages of large-size graded crushed stone under cyclic rotating axial compression: elastic stability, plastic creep, and incremental plastic failure. Large-size graded crushed stone has a higher critical stability load stiffness than conventional-size graded crushed stone. The critical shakedown load of the specimen is mainly affected by the skeleton structure performance, and the critical failure load by the properties of the crushed stone material. Increasing the content and compactness of large-size crushed stone in the specimen can improve the stiffness and stability performance, and to achieve improvements, the content of large-size crushed stone should be controlled between 22% and 26%. The critical shakedown load increases with the increase in the California bearing ratio (CBR) value, while, on the other hand, the CBR value has little relationship with the critical failure load.
本文研究了用于道路基层或垫层的大粒径级配碎石在反复荷载作用下的稳定性。采用自行研制的装置，通过振动旋转压实法对大粒径碎石混合料进行压实成型。施加循环旋转轴向压缩，利用安定理论研究大粒径碎石试件的累积变形。分析了级配参数对累积应变和稳定性能的影响，并根据安定理论确定了临界稳定和破坏荷载。试验结果表明，大粒径级配碎石在循环旋转轴向压缩下存在三个明显的失稳行为阶段：弹性稳定、塑性蠕变和增量塑性破坏。大粒径级配碎石比常规粒径级配碎石具有更高的临界稳定荷载刚度。试件的临界安定荷载主要受骨架结构性能影响，临界破坏荷载受碎石材料性能影响。增加试件中大粒径碎石的含量和压实度可提高刚度和稳定性能，为实现改进，大粒径碎石的含量应控制在22%至26%之间。临界安定荷载随加州承载比（CBR）值的增加而增加，而另一方面，CBR值与临界破坏荷载关系不大。
