基于CT扫描探究颗粒形状和固结压力对机制砂宏微观力学特性的影响  

The influence of particle shape and consolidation pressure on the macro-and micro-mechanical properties of mechanism sand based on CT Scanning

作　　者：黄刚[1] 吴大志[1] 王喆 黄鋆溢 HUANG Gang;WU Dazhi;WANG Zhe;HUANG Junyi(School of Civil Engineering and Architecture,Zhejiang Sci-Tech University,Hangzhou 310018,China;Faculty of Engineering,Lishui University,Lishui 323000,China)

机构地区：[1]浙江理工大学建筑与工程学院,杭州310018 [2]丽水学院工学院,浙江丽水323000

出　　处：《黑龙江工程学院学报》2025年第2期31-37,共7页Journal of Heilongjiang Institute of Technology

基　　金：国家自然科学基金项目(52408369);浙江省自然科学基金项目(LY23E080004)。

摘　　要：在土体沉积过程中,颗粒的形状、粒径及其排列方式是决定其各向异性力学特性的重要因素。为了深入探讨各向异性机制砂的宏观与微观特性之间的联系,文中基于CT扫描建立了真实颗粒形状的单剪离散元模型,探究2种真实形状的机制砂颗粒(卵球状Ball、长条状Bar)分别在不同的固结压力(100、200、400 kPa)下单剪宏细观力学行为。研究结果表明,颗粒形状和固结压力对机制砂的初始各向异性具有显著影响。随着初始竖向固结压力的增加,试样的抗剪强度和等效孔隙水压力峰值也随之增大。相比之下,卵球状颗粒在不同固结压力下表现出更高的剪切强度,而长条状颗粒的等效孔压峰值较高,且出现在更大的剪应变处。细观分析显示,接触滑动占比和接触法向各向异性与颗粒内部的微观相互作用密切相关。高固结压力下,滑动接触占比较低,颗粒间的接触网络更为稳定;而低固结压力下,长条状颗粒的法向各向异性显著,表现出更复杂的演化规律。整体而言,颗粒形状和固结压力的交互作用显著影响了机制砂的力学行为和结构稳定性。During soil sedimentation,the shape,size,and arrangement of particles are critical factors determining the anisotropic mechanical properties of the soil.To explore the relationship between the macro and micro characteristics of anisotropic mechanism sand,this study employs CT scanning to develop a discrete element method(DEM)model of simple shear tests using particles with realistic shapes.The investigation focuses on two types of mechanism sand particles(ellipsoidal Ball and elongated Bar)under different consolidation pressures(100,200,and 400 kPa)to assess their macro-micro mechanical behavior during shear.The results reveal that particle shape and consolidation pressure significantly influence the initial anisotropy of mechanism sand.As the initial vertical consolidation pressure increases,the shear strength and peak equivalent pore water pressure also increase.The ellipsoidal Ball particles exhibit higher shear strength across different consolidation pressures,while the elongated Bar particles show higher pore water pressure peaks,which occur at larger shear strains.Microstructural analysis indicates that the proportion of sliding contacts and contact normal anisotropy are closely related to the microscopic interactions between particles.Under high consolidation pressure,the proportion of sliding contacts is lower,resulting in a more stable contact network.Conversely,under low consolidation pressure,the elongated Bar particles exhibit significant normal contact anisotropy,with more complex evolutionary patterns.Overall,the interaction between particle shape and consolidation pressure significantly affects the mechanical behavior and structural stability of mechanism sand.

关 键 词：机制砂 CT 真实颗粒形状 离散元 各向异性 

分 类 号：TU411[建筑科学—岩土工程]