为了加强对三维裂纹扩展机理的认识,采用一种脆度良好的树脂材料制作含预制三维双裂隙的试样,并基于离散元理论,研究在单轴压缩条件下平行双裂隙的扩展、搭接和贯通机理,同时设置测量圆来监测在不同加载阶段模型的应力场变化。研究结果表明:预制裂隙长轴端部C1-E和C2-W萌生的翼裂纹沿垂直裂隙平面方向扩展至一定长度后会保持长时间不变,直到应力达到峰值附近才继续沿着最大主应力方向扩展;在峰值应力附近时,预制裂隙端部C1-W和C2-W的花瓣状翼裂纹和反翼裂纹才相互搭接贯通形成空间卷曲面;随着轴向应力增加至峰值附近,最大主应力主要分布在远离预制裂隙的区域,而压应力却集中在预制裂隙中心区域,因此抑制了翼裂纹的进一步扩展;最大压应力和切应力随着应变增加而增加,最大拉应力却在峰值应力附近发生了跌落,说明在加载后期,裂纹扩展主要受压剪作用力控制。
Abstract
For a better understanding of the evolution mechanism of 3-D crack propagation in brittle rock mass, the mechanism of 3-D crack propagation, coalescence and overlap in rock-like materials (a newly developed resin) with pre-existing double flaws under uniaxial compression is investigated based on the discrete element theory. Meanwhile, measurement circles are employed to monitor the variation of stress field of the model at different loading stages. The results reveal that wing cracks initiated from the long shaft ends of the pre-existing flaws C1-E and C2-W propagate towards the vertical direction of flaw plane to a certain length and then remain unchanged for a long time, and continue to propagate along the direction of the maximum principal stress when the stress reaches the peak. When axial stress reaches around the peak, petal-like wing cracks and reverse-wing cracks at the ends of the pre-existing flaws C1-W and C2-W coalesce and form a curling surface. As the axial stress increases to the vicinity of the peak, the maximum principal stress is mainly distributed in areas away from the pre-existing flaws, while the compressive stress is concentrated in the central region of the pre-existing flaws, thus imposing restrictions on the further propagation of the wing cracks. The maximum compressive stress and shear stress increase with the increasing strain while the maximum tensile stress drops near the peak stress, indicating that the crack propagation is mainly controlled by the compressive shear force in the later stage of loading.
关键词
三维裂纹扩展 /
压缩试验 /
离散元法 /
应力场 /
测量圆
Key words
3-D crack propagation /
compression test /
discrete element method /
stress field /
measurement circle
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] 牛江瑞, 姚 池, 杨建华,等.基于改进刚体弹簧方法的断续双裂隙砂岩强度及裂纹扩展特征研究[J].长江科学院院报,2017,34(10):102-106,113.
[2] 康石磊, 阳军生, 杨 峰.含裂隙类岩试样破坏行为的宏细观数值分析[J].长江科学院院报,2016,33(4):71-77.
[3] BOBET A, EINSTEIN H H. Fracture Coalescence in Rock-type Materials under Uniaxial and Biaxial Compression[J]. International Journal of Rock Mechanics and Mining Sciences, 1998, 35(7): 863-888.
[4] WONG R, CHAU K T, TANG C A,et al. Analysis of Crack Coalescence in Rock-like Materials Containing Three Flaws—Part I: Experimental Approach[J]. International Journal of Rock Mechanics and Mining Sciences, 2001, 38(7): 909-924.
[5] 王笑然, 王恩元, 刘晓斐,等. 裂隙砂岩裂纹扩展声发射响应及速率效应研究[J]. 岩石力学与工程学报, 2018, 37(6):1446-1458.
[6] 唐 谦, 李云安.围压对岩石裂纹扩展影响的颗粒流模拟研究[J].长江科学院院报,2015,32(4):81-85.
[7] 杨横涛, 林 杭.岩样单裂隙几何参数对其破坏模式与强度的影响[J].长江科学院院报,2018,35(3):26-33,44.
[8] 郭彦双, 林春金, 朱维申, 等. 三维裂隙组扩展及贯通过程的试验研究[J]. 岩石力学与工程学报, 2008, 27(增刊 1): 3191-3195.
[9] 郭彦双, 朱维申. 压剪条件下预埋椭圆裂纹三维扩展实验研究[J]. 固体力学学报, 2011, 32(1): 64-73.
[10]ZHOU X P, ZHANG J Z, WONG L N Y. Experimental Study on the Growth, Coalescence and Wrapping Behaviors of 3D Cross-Embedded Flaws Under Uniaxial Compression[J]. Rock Mechanics and Rock Engineering, 2018, 51(5): 1379-1400.
[11]DYSKIN A V, SAHOURYEH E, JEWELL R J, et al. Influence of Shape and Locations of Initial 3D Cracks on Their Growth in Uniaxial Compression[J]. Engineering Fracture Mechanics, 2003, 70(15): 2115-2136.
[12]黄明利, 黄凯珠. 三维表面裂纹相互作用扩展贯通机制试验研究[J]. 岩石力学与工程学报, 2007, 26(9):1794-1799.
[13]黄彦华, 杨圣奇. 非共面双裂隙红砂岩宏细观力学行为颗粒流模拟[J]. 岩石力学与工程学报, 2014, 33(8): 1644-1653.
[14]张社荣, 孙 博, 王 超, 等. 双轴压缩试验下岩石裂纹扩展的离散元分析[J]. 岩石力学与工程学报, 2013,32(增刊2):3083-3091.
[15]ZHANG X, WONG L N Y. Cracking Processes in Rock-like Material Containing a Single Flaw Under Uniaxial Compression: A Numerical Study Based on Parallel Bonded-Particle Model Approach[J]. Rock Mechanics and Rock Engineering, 2012, 45(5): 711-737.
[16]邓清海, 巩林贤, 马凤山, 等. 基于颗粒流的直切槽式巴西圆盘裂纹扩展分析[J]. 工程地质学报, 2017, 25(2):402-409.
[17]ZHANG X, WONG L N Y. Crack Initiation, Propagation and Coalescence in Rock-like Material Containing Two Flaws: A Numerical Study Based on Bonded-Particle Model Approach[J]. Rock Mechanics and Rock Engineering, 2013, 46(5): 1001-1021.
[18]张敦福, 张 波, 王卫东,等. 单向轴压条件下内置椭圆三维裂纹扩展无网格方法的研究[J]. 应用力学学报, 2016,33(3):483-489,50.
[19]付金伟, 朱维申, 周 奎, 等. 岩石中三维单裂隙扩展过程的试验研究和数值模拟[J]. 煤炭学报, 2013, 38(3):411-417.
[20]BI J, ZHOU X P, QIAN Q H. The 3D Numerical Simulation for the Propagation Process of Multiple Pre-existing Flaws in Rock-like Materials Subjected to Biaxial Compressive Loads[J]. Rock Mechanics and Rock Engineering, 2016, 49(5):1611-1627.
[21]ZHANG Y, STEAD D. Modelling 3D Crack Propagation in Hard Rock Pillars Using a Synthetic Rock Mass Approach[J]. International Journal of Rock Mechanics and Mining Sciences, 2014, 72: 199-213.
[22]PARK B, MIN K B. Bonded-particle Discrete Element Modeling of Mechanical Behavior of Transversely Isotropic Rock[J]. International Journal of Rock Mechanics and Mining Sciences, 2015, 76: 243-255.
[23]SCHOLTÉS L, DONZÉ F V. Modelling Progressive Failure in Fractured Rock Masses Using a 3D Discrete Element Method[J]. International Journal of Rock Mechanics and Mining Sciences, 2012, 52: 18-30.
[24]WONG L N Y, EINSTEIN H H. Systematic Evaluation of Cracking Behavior in Specimens Containing Single Flaws under Uniaxial Compression[J]. International Journal of Rock Mechanics and Mining Sciences, 2009, 46(2): 239-49.
[25]DYSKIN A V, JEWELL R J, JOER H, et al. Experiments on 3-D Crack Growth in Uniaxial Compression[J]. International Journal of Fracture, 1994, 65(4): 77-83.
基金
国家自然科学基金面上项目(51879149,51779134,51579142);山东省交通厅科技发展计划(2019b47-1);山东省泰山学者工程项目
PDF(7325 KB)
