Particle breakage of calcareous sand from low-high strain rates  

作　　者：Yaru Lv Jieming Hu Dongdong Zhang Yuan Wang Yuchen Su 

机构地区：[1]College of Mechanics and Materials,Hohai University,Nanjing,210098,China [2]College of Field Engineering,Army Engineering University of PLA,Nanjing,210007,China [3]College of Water Conservancy&Hydropower Engineering,Hohai University,Nanjing,210098,China

出　　处：《Journal of Rock Mechanics and Geotechnical Engineering》2024年第12期5249-5263,共15页岩石力学与岩土工程学报（英文）

基　　金：support of the National Natural Science Foundation of China(Grant Nos.52279097 and 51779264);the China Scholarships Council(Grant No.202306710072)and Blue and Green Project of Jiangsu Province.

摘　　要：The influence of strain rate on the mechanics of particles is well documented.However,a comprehensive understanding of the strain rate effect on calcareous particles,particularly in the transition from static to dynamic loading,is still lacking in current literature.This study conducted 720 quasi-static and impact tests on irregular calcareous particles to investigate the macroscopic strain rate effect,and performed numerical simulations on spherical particles to explore the underlying microscopic mechanisms.The strain rate effect on the characteristic particle strength was found to exhibit three regimes:in Regime 1,the particle strength gradually improves when the strain rate is lower than approximately 10^(2)s^(-1);in Regime 2,the particle strength sharply enhances when the strain rate increases from 10^(2)s^(-1)to 10^(4)s^(-1);and in Regime 3,the particle strength remains almost constant when the strain rate is higher than 10^(4)s^(-1).The three-regime strain rate effect is an inherent property of the material and independent of particle shape.The asynchrony between loading and deformation plays a dominant role in these behaviors,leading to a thermoactivation-dominated effect in Regime 1,a macroscopic viscosity-dominated effect in Regime 2,and a combined thermoactivation and macroscopic viscosity-dominated effect in Regime 3.These mechanisms induce a transition in the failure mode from splitting to exploding and then smashing,which increases the energy required to rupture a single bond and,consequently,enhances the particle strength.

关 键 词：Calcareous particle Strain rate effect Laboratory tests Particle breakage Failure mode 

分 类 号：TU41[建筑科学—岩土工程]