Study on mechanical properties of soil-rock mixture considering the correlation of"particle breakage-shear parameters-water content"
The construction of pumped storage power station produces a large amount of earth-rock mixture to form a waste dam,which has loose structure,poor grading,heavy weight and strong water permeability.If it encounters heavy rainfall,its safety and stability will be seriously affected.Taking the soil-rock mixture of waste dam as the research object,the development law of stress and strain,the characteristics of deform-ation strength and the quantitative study of particle gradation before and after shearing are explored.The test results show that with the increase of water content,the shear strength of the mixture sample decrea-ses,the stress-strain curve shows a hardening trend as a whole,the nonlinear internal friction angle decrea-ses with the increase of water content,and the cohesion first decreases and then increases.With the in-crease of water content,the phase change stress ratio,the volume variable and the dilatancy effect de-crease.With the increase of confining pressure,the results are consistent with the above.By measuring the particle gradation of the mixture before and after shearing,the correlation analysis of particle breakage-shearing parameters-water content of the soil-rock mixture is explored by introducing the breakage index.The results show that when the water content increases and the particle breakage increases,the shear strength decreases greatly,which has a more obvious impact on the safety of the dam.When the water con-tent and breakage degree decrease,the result is the opposite.Finally,the Duncan-Chang model is modified by introducing breakage parameters,and the applicability of the model is demonstrated based on the test results,so as to provide reference for the safety and stability of the follow-up waste dam structure.
shear strengthphase change stress ratioparticle gradationparticle breakageDuncan-Chang model modificationearth-rock mixture
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