单轴压缩条件下类大理岩裂纹起裂特性与扩展规律  

Crack initiation characteristics and propagation law of marble-like rock under uniaxial compression

作　　者：肖桃李[1] 袁浩 折海成 黄梅[1] XIAO Taoli;YUAN Hao;SHE Haicheng;HUANG Mei(School of Urban Construction,Yangtze University,Jingzhou 434023,Hubei,China)

机构地区：[1]长江大学城市建设学院,湖北荆州434023

出　　处：《水利水电技术（中英文）》2022年第8期161-171,共11页Water Resources and Hydropower Engineering

基　　金：岩土力学与工程国家重点实验室开放基金(Z020013);陕西省混凝土结构安全与耐久性重点实验室开放基金(SZ02105);湖北省荆州市科技计划项目(2020AC15)。

摘　　要：在岩体工程中,裂隙构型属性对新生裂纹起裂和扩展规律、破坏模式及力学行为都有着显著影响。以预制含单裂隙类大理岩为研究对象,结合室内单轴压缩试验与PFC数值模拟试验,针对不同裂隙长度和倾角岩样的起裂、扩展、破坏及力学特性进行研究。结果表明:(1)岩样破坏模式主要受裂隙倾角控制,破碎程度主要受裂隙长度控制。(2)岩样加载变形过程中的起裂应力、损伤应力和峰值应力随裂隙倾角的增加而增加,随裂隙长度的增加而减小;裂纹起裂角随裂隙倾角的增大而减小。(3)裂纹的起裂特性为,在低裂隙倾角(即α<45°)时,裂纹从离预制裂隙中心有一定偏移处开始起裂;在高裂隙倾角(即α≥45°)时,裂纹从预制裂隙的尖端开始起裂,最终形成“弥散式”分布。(4)裂纹扩展规律主要以剪切裂纹为主,在低裂隙倾角(即α<45°)时,裂纹的扩展有明显的聚集带形成;在高裂隙倾角(即α≥45°)时,裂纹聚集带逐渐弱化,朝着“弥散式”方向扩展。研究成果对合理评价岩体结构和设施的安全稳定性具有重要的理论意义。Taking the prefabricated marble-like rock with single fissure as the study object, the crack initiation, propagation, failure and mechanical characteristics of the rock samples with different fissure lengths and dip angles are studied herein in combination with the in-door uniaxial compression test and PFCnumerical simulation test. The results show that(1) the failure mode of the rock sample is mainly controlled by the crack dip angle, while its fragmentation degree is mainly controlled by fissure length;(2) the crack initiation stress, damage stress and peak stress of rock sample during the loading deformation process increase with the increase of fissure dip angle and decrease with the increase of fissure length, while the crack initiation angle decreases with the increase of the fissure dip angle;(3) the crack initiation characteristics: the crack initiates from a certain offset from the center of the prefabricated fissure at a low fissure dip angle(α< 45°), while the crack initiates from the tip of the prefabricated fissure and finally forms a dispersed distribution at high fissure dip angle(α≥45°);(4) the crack propagation law is mainly dominated by shear crack, while the crack propagation forms obvious aggregation zone at a low fissure dip angle(α< 45°), which gradually weakens and expands in the direction of dispersion. The study results have important theoretical significance for the reasonable evaluation of the safety and stability of the rock mass structure and the relevant facilities.

关 键 词：预制单裂隙 类大理岩 PFC2D 裂纹起裂 裂纹扩展 

分 类 号：TU41[建筑科学—岩土工程]