室内缩尺级配堆石料力学参数的表征单元体积

Representative elementary volume of mechanical parameter of rockfill material with laboratory scaled gradation

为了寻找室内缩尺级配堆石料强度和变形参数的表征单元体积(REV),利用离散元方法(DEM)研究试样尺寸对玄武岩堆石料力学行为的影响.通过室内单颗粒破碎试验,分析玄武岩颗粒的破碎特性,确定DEM模拟所需的颗粒破碎强度参数.开展一系列试样尺寸、颗粒排列和围压不同的三轴压缩DEM试验.分析堆石料强度和变形参数随试样尺寸的变化规律,建议了各参数的REV.结果表明,颗粒排列和试样尺寸均会影响堆石料的力学行为.各力学参数的变异系数随着试样尺寸的增大而减小.不同力学参数的REV尺寸不同,为了提高DEM计算效率,可以根据研究对象选择合适的试样尺寸.在模拟工况下,要使所有参数均达到稳定,数值试样尺寸应不小于直径300 mm×高度600 mm.

The discrete element method(DEM)was used to analyze the effect of specimen size on the mechanical behavior of basalt rockfill materials in order to find the representative elementary volume(REV)of the strength and deformation parameters of the rockfill materials with laboratory scaled gradation.Laboratory single-particle crushing tests were conducted to analyze the crushing characteristics of basalt particles and determine the particle crushing strength parameters required for DEM simulations.A series of triaxial compression DEM tests with different specimen sizes,particle arrangements and confining pressures were conducted.The variations of strength and deformation parameters with specimen size were analyzed for rockfill materials,and the REV of each parameter was assessed.Results show that particle arrangement and specimen size both impact the mechanical behavior of basalt rockfill materials.The variation coefficient of each mechanical parameter decreases as specimen size increases.The REV size of different mechanical parameters is different.The appropriate specimen size can be selected according to the research object in order to improve the calculation efficiency of DEM.The size of the numerical sample should not be less than 300 mm in diameter and 600 mm in height in order to make all parameters stable under the simulated conditions.