超重力模型试验干–饱和砂动剪切模量阻尼比特性研究

doi:10.13722/j.cnki.jrme.2022.0830

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Abstract Dynamic shear modulus and damping ratio are significant dynamic indicators of soil dynamics and geotechnical earthquake engineering，and their constitutive relationships are mostly established and recognized based on unit tests. Compared with the unit tests，the centrifuge model tests have more realistic stress boundaries，loading schemes and drainage conditions，but there are rarely studies on dynamic modulus and damping ratio. The form differences of the shear stress- strain hysteresis loop of dry sand and saturated sand are revealed，and the characteristics and laws of dynamic modulus and damping ratio with burial depth，shear strain and vibration order are compared based on the centrifuge model comparison tests. The results show that the hysteresis cycle of dry sand is oval，but the hysteresis cycle of saturated sand is irregular and non-smooth dumbbell shape. The shear strain of saturated sand increases rapidly after liquefaction，and the maximum shear strains of dry sand and saturated sand under 0.2 g load are 0.3% and 1%，respectively. The dynamic shear moduli of dry sand and saturated sand obey the Hardin hyperbola model well，which decrease with the increase of shear strain，increase with the increase of burial depth，and increase with the increase of vibration times，which causes the soil vibration density. The maximum dynamic shear modulus and their changes with depth and vibration order are basically the same，and are less affected by saturation. The reference strains of dry sand and saturated sand are 0.1%–0.35% and 0.05%–0.18%，respectively，and the reference strains of dry sand under different depths and loads are about twice that of the saturated sand，and they increase with the increase of burial depth and density. The damping ratio of dry sand has a good law with the variation of shear strain and burial depth，and the discreteness is small. However，the damping ratio of saturated sand is not obvious，and the discreteness is large，which is related to the change of sensor position，the test accuracy and the reliability of the analysis method caused by the failure of the soil strength after liquefaction. The research results provide technical support and guidance for understanding the response characteristics of the dynamic modulus and damping ratio of the centrifuge model test and for comparing the reliability of the dynamic modulus and damping ratio in the unit test.

Key words： soil mechanics dynamic centrifuge test shear modulus damping ratio inverse analysis

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	WANG Tiqiang1
	2
	WANG Yongzhi1
	2
	LIANG Xiaocong3
	WANG Deyong3
	CHEN Zhuoshi1
	2

Cite this article:

WANG Tiqiang1,2,WANG Yongzhi1, et al. Study on the characteristics of shear modulus and damping ratio between dry sand and saturated sand in centrifuge model test[J]. , 2023, 42(6): 1546-1559.

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http://rockmech.whrsm.ac.cn/EN/10.13722/j.cnki.jrme.2022.0830 OR http://rockmech.whrsm.ac.cn/EN/Y2023/V42/I6/1546