Behaviors of dynamic modulus and damping ratio of loess in Gannan region of Gansu Province
WANG Qian1, LI Na1, WANG Ping1, HOU Peng-bo2, ZHONG Xiu-mei1, WANG Jun1, WANG Hui-juan1
1. Key Laboratory of Loess Earthquake Engineering, China Earthquake Administration & Gansu Province, Lanzhou 730000, China, 2. Energy China GSEPDI, Lanzhou 730000, China
Abstract：The dynamic constitutive relation of redeposited loess in Gannan region is investigated based on the dynamic triaxial tests. The model parameters are obtained, and the behaviors of dynamic shear modulus ratio and damping ratio are analyzed. The attenuation model for the dynamic shear modulus and the growth model for the damping ratio with dynamic shear strain are provided. Moreover, the differences about the shear modulus ratio and damping ratio between redeposited loess and eolian loess are discussed depending on the normalization processing and comparison of model parameters. The results show that the dynamic constitutive relation of redeposited loess obeys the hyperbolic model, and the value of model parameter a has no obvious difference with that of the eolian loess, but the value of b is 1.5 times that to 3 times that of the eolian loess under the same condition. The original dynamic elasticity modulus Edmax of redeposited loess is greatly influenced by the consolidation condition and the loess density, and under the same condition, the value Edmax of residual loess is smaller than that of alluvia loess. The dynamic shear modulus ratio of redeposited loess decreases with the increase of dynamic shear strain, and the variation trend of shear modulus ratio presents a tendency of negative exponential attenuation model. The trend of D ~γd obeys the logarithmic relationship which increases with the increase of dynamic shear strain. Compared with that of the eolian loess, the attenuation rate of the dynamic shear modulus of the redeposited loess is more quickly, and the increase range of the damping ratio is relatively narrow, which indicates the obvious influences of sedimentary environment on the differences of dynamic properties of loess.
王谦,李娜,王平,侯鹏博,钟秀梅,王峻,王会娟. 甘南地区黄土的动模量与阻尼比特性研究[J]. 岩土工程学报, 2017, 39(s1): 192-197.
WANG Qian, LI Na, WANG Ping, HOU Peng-bo, ZHONG Xiu-mei, WANG Jun, WANG Hui-juan. Behaviors of dynamic modulus and damping ratio of loess in Gannan region of Gansu Province. Chinese J. Geot. Eng., 2017, 39(s1): 192-197.
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