(1. State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam，Chongqing University， Chongqing 400044，China；2. State Key Laboratory of Geomechanics and Geotechnical Engineering，Institute of Rock and Soil Mechanics，Chinese Academy of Sciences，Wuhan，Hubei 430071，China；3. Faculty of Land Resources Engineering，Kunming University of Science and Technology，Kunming，Yunnan 650093，China)
Abstract：The mechanical properties of tailings are affected by the silt content，but so far，studies related to the influence mechanism of silt content on the mechanical properties are not much. This paper presents the investigation on the effects of silt content on the mechanical property of tailings and its mesoscopic mechanism. The microscopic observation，the triaxial test and the discrete element simulation were performed to study the microscopic characteristics of sand and silt. The critical silt content is analyzed based on the results of the experiment. Finally，we proposed a mesoscopic mechanism of silt content effect. The silt and sand particles are different in size distribution，angularity and surface topography. The tiny particles(＜30 ?m) have the unique microscopic features. The sandy tailing is transformed into the silty tailing with the increase of silt content，and the critical content is 30%–50%. It is theoretically proved that the smaller of silt particle size and the elastic modulus are，the bigger the deformation of soil is. Mesoscopically，the increase of salt content weakens the original force chain，thus resulting in the silt content effect.
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2017, Vol. 36 
