In this paper, the X-ray micro-computed tomography (X-ray μCT), spherical harmonical-based principal component analysis (SH-PCA) and discrete element method (DEM) were incorporated to generate virtual samples with morphological gene mutation at different length scales. All samples were subjected to axial compression and constant confining stress. The effects of multiscale particle morphology on the stress-strain and energy storage/dissipation responses of granular soils were investigated. It is found that: (a) the effects of particle morphology on the initial stiffness, stress-strain, volumetric strain and frictional energy dissipation behaviours are more pronounced for looser samples than for denser ones; (b) among different length scales, the particle morphology at the local roundness-level outperforms the one at the general form-level in dictating the macro-scale responses of granular soils; (c) the energy dissipation of a granular assemblage is a result of competition between particle morphology and initial void ratio. © Zhejiang University Press 2022.

目的
本文旨在探討不同尺度顆粒形貌特徵對於砂土應力-應變以及能量耗散行為的影響。

方法
1. 通過同步X射線計算斷層掃描實驗,提取高精度的真實顆粒形貌,並通過三維點雲表徵; 2. 通過基於球諧分析的主成分分析方法,構建不同尺度下顆粒形貌的突變與衰減; 3. 通過離散單元法模擬,類比不同形貌試件的三軸剪切過程,並進一步討論不同尺度顆粒形貌對於顆粒材料應力-應變以及能量耗散行為的影響。

結論
1. 通過比較較鬆散和較密實的試件,發現對於較鬆散試件,顆粒形貌對顆粒材料的初始剛度、應力-應變、體積應變和摩擦能量耗散等響應的影響更為明顯; 2. 對於不同尺度下的顆粒形貌,局部圓度較長徑比對顆粒材料宏觀響應的影響更大; 3. 顆粒材料的能量耗散行為由顆粒形貌和初始孔隙率共同決定。