Experimental study on the stress-strain and strength characteristics of loose rock-soil aggregates based on large-size stacked ring shear test
JIANG Jiwei，CHENG Zhanlin，PAN Jiajun，ZUO Yongzhen
(Key Laboratory of Geotechnical Mechanics and Engineering of Ministry of Water Resources，Yangtze River Scientific Research Institute，Wuhan，Hubei 430010，China)
Loose rock-soil aggregates(LRA) is widespread in nature environment and practical engineering. A kind of LRA that composed by strong weathered slate is selected as the research object. Firstly，the sample preparation method for LRA is achieved successfully，then based on large-size stacked ring shear apparatus，a series mechanical tests for LRA under different relative density(Dr) and different dry and wet state is conducted，the research shows that，because the restraint effect and mechanical bite among LRA is weak，the peak value in stress-strain curve is not significant，the big deformation mainly composed by interparticle friction and rolling；for the three Dr(0.30，0.35 and 0.40 respectively) conditions in experiment，when LRA keep dry state，the friction angle slightly increased from 13.18°(Dr=0.30) to 13.97°(Dr=0.40)，and cohesion slightly decreased from 6.95 kPa (Dr=0.30) to 4.90 kPa (Dr=0.40)， it means the strength of LRA nearly keeps stable in this loose range，and when the sample is wet or submerged in water also meet to this law；the peak shear stress of dry LRA is much higher than that in wet and submerged in water，the water sensitivity characteristic is obvious；Dr = 0.40 is selected as a case study, based on a comparative test，it¢s clear that in researching engineering properties of LRA，stacked ring shear test is more advantages and applicability than conventional triaxial test. This research preliminarily reveals the strength and deformation characteristics of LRA，obvious water sensitivity of LRA are very useful in quantitatively explain the mechanism for large deformation and failure of loose deposit and landslide.
江洎洧，程展林，潘家军，左永振. 基于大型叠环剪切试验的松散土石体强度及变形特性试验研究[J]. 岩石力学与工程学报, 2017, 36(S1): 3636-3643.
JIANG Jiwei，CHENG Zhanlin，PAN Jiajun，ZUO Yongzhen. Experimental study on the stress-strain and strength characteristics of loose rock-soil aggregates based on large-size stacked ring shear test. , 2017, 36(S1): 3636-3643.
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2017, Vol. 36 
