摘要
为了研究轴向表面裂隙形态对岩石动态力学特性及破坏模式的影响,将直径×高度为50 mm×50 mm的圆柱形黄砂岩分别加工成裂隙深度为5,10和15 mm及裂隙数量为1,2,3和4条的不同类别试样,采用改进的分离式霍普金森压杆实验系统对其进行动静组合加载实验,并借助高速摄像仪观察裂纹扩展及动态破坏过程。研究结果表明:裂隙岩样的动态抗压强度、变形模量和峰值应变随裂隙数量和深度增大而先增大后减小;裂隙岩样变形由裂隙压密闭合阶段、弹性阶段、非线性塑性变形阶段和峰后阶段组成,呈现显著的塑性特征;裂隙岩样的破坏模式比较复杂,主要有剥落破坏、拉剪破坏、剥落贯通破坏和拉伸贯通破坏4种;随着裂隙深度增大,试样能量吸收率和能耗密度先减小后增大;与其他含不同裂隙数量的岩样相比,裂隙数量为2时岩样能量吸收率和能耗密度较小,表明该类试样的破碎块度较大,这与采用分形理论描述的岩石破坏特征基本相符。
To study the effects of axial surface cracks on rock dynamic mechanical properties and failure modes,a series of cylindrical yellow sandstones with a diameter of 50 mm and a height of 50 mm were processed into different types of specimens with cracks of 5,10 and 15 mm in depth as well as 1,2,3 and 4 in quantity.The improved split Hopkinson pressure bar(SHPB)testing system was used to carry out the impact loading test under coupled static-dynamic loads.Crack propagation and the dynamic failure process were also monitored by a high speed camera.The results show that dynamic compressive strength,deformation modulus and peak strain of specimens increase firstly and then decrease with the increase of crack number and crack depth.The deformation process of fractured specimens can be subdivided into four stages:pore compaction-induced closure,elastic stage,non-linear plastic deformation stage and post-peak stage,showing significant plastic properties.There are four types of failure modes for fractured specimens,namely,spalling failure,tensile-shear failure,spalling coalescence failure and tensile coalescence failure.With the increase of crack depth,the energy absorption rate and energy density of the samples decrease firstly and then increase.The energy absorption rate and energy density of fractured specimens containing 2 cracks are the minimum among all specimens.The indicates that the fragmentation of this kind of sample is larger,which basically agrees with the failure characteristics described by the fractal theory.
作者
吴浩
赵国彦
梁伟章
王恩杰
WU Hao;ZHAO Guoyan;LIANG Weizhang;WANG Enjie(School of Resources and Safety Engineering,Central South University,Changsha 410083,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2019年第2期350-359,共10页
Journal of Central South University:Science and Technology
基金
国家自然科学基金资助项目(51774321)
中央高校基本科研业务费专项资金资助项目(2018zzts215)~~
