Experimental research on microstructure characteristics of structural soft clays under cyclic loading
YANG Aiwu1，2，GOU Leyu1，2，ZHANG Zhendong1，2
(1. Department of Civil Engineering，Tianjin Chengjian University，Tianjin 300384，China；2. Key Laboratory of Soft Soil Engineering Characteristics and Engineering Environment of Tianjin，Tianjin Chengjian University，Tianjin 300384，China)
Abstract：Dynamic triaxial tests are performed for typical soft clays from Binhai New District in Tianjin to study the microstructure characteristics of structural clays under dynamic loads. Soil samples after the specific numbers of loading cycles are sliced and scanned with SEM. The research focuses on the effects of different cyclic stress ratios，the number of cycles and the cell pressures on the microstructure variation of soft clays. The test results show that the numbers of particles and pores increase with the increase of cyclic stress ratio，the number of cycles and the cell pressure，and on the contrary，the equivalent diameter and the shape ratio of particles and pores decrease. The microstructure tends to be stable with the increase of the number of cycles when the cyclic stress amplitude is less than a critical value. However，the microstructure changes constantly with the increase of the number of cycles when the cyclic stress amplitude is greater than or equal to the critical amplitude. Microstructure parameter values have obvious changes during the cyclic loading when the cell pressure is around the consolidation yield stress. Different microstructure parameter values change with the number of cycles logarithmically with good correlation.
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2017, Vol. 36 
