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In situ shear modulus and shear strain decay curves in expansive soils and analysis of its characteristics#br# |
LI Jingjing1,2,KONG Lingwei1,2,JIN Lei3 |
(1. State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan,Hubei 430071,China;2. University of Chinese Academy of Sciences,Beijing 100049,China;3. School of Civil Engineering,Wuhan University,Wuhan,Hubei 430072,China)
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Abstract In order to evaluate the characteristics of stiffness decay of expansive soil at the in-situ stress state under the small strain condition,the in-situ seismic dilatometer test and the resonant column test are carried out to analyze the influence of stress history,stress state and disturbance on the modulus decay of expansive soil. Results show that both the stress state and stress history significantly affect the shear modulus of expansive soil. The shear modulus increases with the increasing of the confining pressure under the same stress path and the modulus decays faster with the development of shear strain. The shear modulus of soils following the loading-unloading path is greater than that of soils only following the loading path,while the G-? decay curve of former is nearly the same as that of soils following the loading-unloading-reloading path. Besides,the in-situ shear modulus is greater than that from the resonant column tests of the same stress history,which indicates that disturbance caused by sampling,unloading,transportation and sample preparation contributes to the irreversible damage,so that the in-situ characteristics were not be presented in the indoor test results following the loading and unloading path. The in-situ G-? decay curves derived with different reference strains exhibit an evident difference in the middle strain range,which shows the shear modulus decays faster with smaller reference strain. Selecting a reasonable reference curve and the shear modulus of small strain are the key to get the right in-situ G- decay curves.
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Cite this article: |
LI Jingjing1,2,KONG Lingwei1, et al. In situ shear modulus and shear strain decay curves in expansive soils and analysis of its characteristics#br#[J]. , 2017, 36(4): 1032-1039.
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URL: |
http://www.rockmech.org/EN/Y2017/V36/I4/1032 |
[15] |
MARCHETTI S,MONACO P,TOTANI G,et al. In situ tests by seismic dilatometer(SDMT)[J]. From Research to Practice in Geotechnical Engineering,2008,180:292-311.
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