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| Experimental research on long-term dynamic characteristics of unsaturated road base and subbase mixtures |
| CHEN Jingyu1，CAI Yuanqiang1，2，CAO Zhigang1，LI Fuyou3，GU Chuan4 |
(1. Research Center of Coastal and Urban Geotechnical Engineering，Zhejiang University，Hangzhou，Zhejiang 310058，China；2. College of Civil Engineering and Architecture，Zhejiang University of Technology，Hangzhou，Zhejiang 310014，China；
3. Zhejiang Huaheng Transportation Engineering Supervision Limited Company，Shaoxing，Zhejiang 312000，China；
4. Architecture and Civil Engineering College，Wenzhou University，Wenzhou，Zhejiang 325035，China) |
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Abstract The large-scale triaxial apparatus GDS was upgraded with an unsaturated testing module to study the long-term dynamic characteristics of unsaturated road base and subbase materials. The testing materials were taken from a common quarry in Zhejiang Province and mixed with kaolin at a mass ratio 3% to simulate the actual road base and subbase materials. During the tests，the axis-translation method was used to control the matric suction. A series of large-scale cyclic triaxial tests were conducted on the crushed tuff aggregate mixtures under four initial matric suctions and two cyclic stress amplitudes. Special attention was paid to the effects of the initial matric suction on the accumulated axial strain and resilient modulus. The testing results indicate that the soil-water characteristic curve(SWCC) of the unsaturated materials presents a hysteresis phenomenon in the water retention tests. For the same matric suction，the moisture content in the drying path is higher than that in the wetting path. Under cyclic loadings，the resilient modulus increases with the increasing of matric suction. The influence of initial matric suction on resilient modulus is more obvious at smaller matric suctions(0–30 kPa) than at larger matric suctions. The accumulated axial strain decreases with the increasing of matric suction，and the decreasing rate also declines with the increasing of matric suction. A nonlinear relationship exists between the accumulated axial strain and matric suction，and a linear relationship exists between the accumulated axial strain and moisture content.
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2018, Vol. 37 
