Experimental study on dynamic characteristics of unbound granular materials under cyclic loading with different frequencies
CAI Yuanqiang1，ZHAO Li1，CAO Zhigang1，GU Chuan2，3
(1. Research Center of Coastal and Urban Geotechnical Engineering of Zhejiang University，Hangzhou，Zhejiang 310058，China；
2. Architecture and Civil Engineering College，Wenzhou University，Wenzhou，Zhejiang 325035，China；3. Key Laboratory of Engineering and Technology for Soft Soil Foundation and Tideland Reclamation of Zhejiang Province，Wenzhou University，Wenzhou，Zhejiang 325035，China)
Abstract：The frequencies of traffic loading vary with various factors such as traffic speed. Currently there is no unified understanding in the load frequency effects on the long-term behavior of road base under the cyclic traffic loading. In order to investigate the effects of loading frequency，a series of large-scale cyclic triaxial tests on the Unbound Granular Materials(UGMs) under saturated drained condition were conducted with GDS large-scale cyclic triaxial apparatus(LDCTTS). The influence of loading frequency on the long-term performance of UGMs was investigated systematically under various stress paths. The experimental results showed that the loadings with higher frequency resulted in a larger accumulated volume contraction during the stage of densification，and consequently the UGMs reached a higher rebounding modulus. The accumulated axial strain of UGMs was also different under the loadings with different frequencies. At the stage of densification of UGMs，the loadings with the higher frequency led to higher accumulated axial strain when the cyclic stress ratios were high(ζ = 3，5)，while the loading frequency effect was minimized when the cyclic stress ratio was low(ζ = 1). After the UGMs reached the stable deformation stage，the loading frequency had almost no influence on the accumulated axial strain. This study has revealed the dynamic behavior of UGMs under the cyclic loading with different frequencies. It is found that the effects of loading frequency on the long-term performance of road base can be greatly reduced by controlling the cyclic stress ratio in the UGMs to a low level. This study can be served as reference for the accurate prediction and control of road post-construction settlement.
蔡袁强1，赵 莉1，曹志刚1，谷 川2，3. 不同频率循环荷载下公路路基粗粒填料长期动力特性试验研究[J]. 岩石力学与工程学报, 2017, 36(5): 1238-1246.
CAI Yuanqiang1，ZHAO Li1，CAO Zhigang1，GU Chuan2，3. Experimental study on dynamic characteristics of unbound granular materials under cyclic loading with different frequencies. , 2017, 36(5): 1238-1246.
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2017, Vol. 36 
