基于平面黏结接触模型模拟平台巴西圆盘的动态响应和破坏机制  

Dynamic Response and Failure Mechanism of Flattened Brazilian Disc Specimens Based on Flat-joint Bonded Particle Material

作　　者：梁尔祝 耿威 方定星 刘鑫 LIANG Erzhu;GENG Wei;FANG Dingxing;LIU Xin(Ansteel Mining Blasting Co.,Ltd.,Anshan 114046,China;School of Mining Engineering,University of Science and Technology Liaoning,Anshan 114051,China)

机构地区：[1]鞍钢矿业爆破有限公司,辽宁鞍山114046 [2]辽宁科技大学矿业工程学院,辽宁鞍山114051

出　　处：《金属矿山》2021年第12期124-131,共8页Metal Mine

摘　　要：应变率对岩石破坏机理的影响是岩石领域最重要的方面之一,借助颗粒流程序及其内置的平面黏结接触模型,构建平台角度是20°和直径是50 mm的花岗岩平台巴西圆盘数值模型,从细观力学角度深入探究不同应变率条件下花岗岩平台巴西圆盘的破裂模式和破坏机制。研究表明:花岗岩平台巴西圆盘的破裂模式主要分为2种破裂模式:微破裂裂纹由中心起裂的破裂模式和伴生压碎区的复合微破裂裂纹共同作用的破裂模式,其中,在中低应变率条件下满足劈裂拉伸试验要求,高应变率条件下已不满足劈裂拉伸试验要求,但对于高应变率的工程问题具有一定指导意义;随着应变率的递增,试样的损伤程度、诱发微破裂裂纹数量和失效机制均发生了变化,剪切型微破裂裂纹数目的增量趋势明显大于拉伸型微破裂裂纹数目的增加,即剪切微破裂裂纹数目的增加是导致试件动态强度增加的主要原因之一;应力与计算时步曲线展示了3种模式,即峰后强化、峰后弱化和单峰值,拉伸型微破裂优先于剪切微破裂生成,在低应变率情况时,剪切型微破裂裂纹产生在第一应力峰值的下降阶段处,拉伸型微破裂裂纹数目呈现的突变现象,在中高应变率情况时,随着应变率的提高,剪切型微破裂裂纹的产生在由应力达到应力峰值之后转变为产生在应力达到应力峰值之前,存在拉伸型微破裂和剪切型微破裂呈现共生现象,且具有剪切型微破裂裂纹数目高于拉伸型微破裂裂纹数目的时刻。The effect of strain rate on rock failure mechanism is one of the most important aspects in rock field.A numerical model of Flattened Brazilian Disc of the Granite to reflect the feature of mineral grain in rock was established using the flat-joint contact model based upon the particle flow code,the fracture mode and failure mechanism of the Flattened Brazilian Disk of the Granite under different strain rates were investigated in detail from the meso mechanical perspective.The fracture mode of the Flattened Brazilian Disk of the Granite is mainly divided into two types,which are central micro-fracture cracks initiation and composite micro-fracture cracks with crushed zone,however,the requirements of splitting tensile test are met under the conditions of low and medium strain rate,and the condition of splitting tensile test is not satisfied under the condition of high strain rate,and it has certain guiding significance to the engineering problem of high strain rate.With the increase of strain rate,the damage degree of the sample,the number of induced micro-fracture cracks and the failure mechanism have changed.The incremental trend of the number of shear-type micro-fracture cracks is obviously larger than the increase of the number of tensile-type micro-fracture cracks.The increase in the number of shear microfracture cracks is one of the main reasons for the increase in the dynamic strength of the specimen.Stress and calculated time-step curves show three modes,namely post-peak enhancement,post-peak weakening,and single peak.Stretch-type micro-cracking takes precedence over shear micro-cracking.At low strain rate,the shear microfracture crack occurs at the falling stage of the first stress peak,and the number of tensile microfracture cracks shows a sudden change.In the case of medium to high strain rate,as the strain rate increases,the generation of shear-type micro-fracture cracks changes from stress to stress peak to occur before the stress reaches the stress peak,and there are tensile micro-fracture and shear

关 键 词：岩石力学 细观力学 平台巴西圆盘 平面粘结接触模型 应变率 破坏机制 

分 类 号：TU45[建筑科学—岩土工程]