Journal of Liaoning Petrochemical University

Journal of Liaoning Petrochemical University ›› 2024, Vol. 44 ›› Issue (2): 42-49.DOI: 10.12422/j.issn.1672-6952.2024.02.007

• Oil and Gas Engineering • Previous Articles     Next Articles

Numerical Simulation of Mechanical Properties and Damage Modes of Shales with Cross⁃Fractures under Triaxial Stress

Heng QU(), Zhonghu WU()   

  1. School of Civil Engineering,Guizhou University,Guiyang Guizhou 550025,China
  • Received:2023-11-24 Revised:2023-12-18 Published:2024-04-25 Online:2024-04-24
  • Contact: Zhonghu WU

三轴应力下含交叉裂缝页岩的力学特性及破坏模式数值模拟

瞿恒(), 邬忠虎()   

  1. 贵州大学 土木工程学院,贵州 贵阳 550025
  • 通讯作者: 邬忠虎
  • 作者简介:瞿恒(1999⁃),男,硕士,从事岩石破坏机理的理论及模拟方法的研究;E⁃mail:quhenggzu@163.com
  • 基金资助:
    贵州省科技计划项目(黔科合支撑[2020]4Y046)

Abstract:

In order to study the influence of cross?fracture on the mechanical properties and damage modes of deep shale, and better understand the damage evolution law of shale containing cross?fracture under high temperature and high pressure coupling, 15 groups of shale models containing cross?fracture with different inclination angles were established, and simulation experiments were carried out to study the stress?strain relationship, damage evolution and acoustic emission characteristics of the shale specimens. The results show that the compressive strength and modulus of elasticity of shale are negatively correlated with the inclination angle of the main cracks, and show an upward concave trend with the increase of the inclination angle of the secondary cracks, and the compressive strength of shale decreases significantly when there are cracks perpendicular to or close to perpendicular to the loading direction; the damage modes of shale specimens under the influence of cross?cracks are mainly divided into "X"?shaped damage, diagonal "N"?shaped damage, diagonal "W"?shaped damage, inverted "V"?shaped damage, damage along the main crack, "V"?shaped damage and "λ"?shaped damage; the fractal dimension of shale specimens is negatively correlated with the inclination angle of the main crack, and as the inclination angle of the main crack decreases, the value of fractal dimension tends to increase, and the corresponding damage pattern of the specimens is more complicated and the internal damage is more intense.

Key words: Shale, Thermosolid coupling, Cross?fracture, Acoustic emission, Fractal dimension

摘要:

为研究交叉裂缝对深层页岩力学特性及破坏模式的影响,更好地了解在高温高压耦合作用下含交叉裂缝页岩的损伤演化规律,建立了15组含不同倾角交叉裂缝页岩模型,并对页岩试件的应力?应变关系、损伤演化及声发射特征进行了模拟实验。结果表明,页岩的抗压强度和弹性模量与主裂缝倾角整体呈负相关,并随次裂缝倾角的增大呈上凹的变化趋势;当页岩中存在垂直或接近垂直于加载方向的裂缝时,其抗压强度显著下降;页岩试件的破坏模式在交叉裂缝影响下主要分为“X”形破坏、斜“N”形破坏、斜“W”形破坏、倒“V”形破坏、沿主裂缝贯穿破坏、“V”形破坏与“λ”形破坏;页岩试件的分形维数与主裂缝倾角整体呈负相关,随着主裂缝倾角的减小,分形维数整体趋于增大,相应的试件破坏模式更复杂,内部损伤更剧烈。

关键词: 页岩, 热固耦合, 交叉裂缝, 声发射, 分形维数

CLC Number: 

Cite this article

Heng QU, Zhonghu WU. Numerical Simulation of Mechanical Properties and Damage Modes of Shales with Cross⁃Fractures under Triaxial Stress[J]. Journal of Liaoning Petrochemical University, 2024, 44(2): 42-49.

瞿恒, 邬忠虎. 三轴应力下含交叉裂缝页岩的力学特性及破坏模式数值模拟[J]. 辽宁石油化工大学学报, 2024, 44(2): 42-49.