实验研究I/II/III混合模式破裂特征在爬行负载下的结合岩石质量
Shuai Li1, Chao Zheng2, Peng Li3
1School of Civil and Transportation Engineering, Henan University of Urban Construction, Pingdingshan, People's Republic of China. li-82.28@163.com.
Scientific reports
|May 6, 2024
概括
这项研究研究了在爬行负荷下岩石断裂,发现更大的关节角度增加了岩石强度,并揭示了新的爬行损伤变量 (D). 这有助于理解深层地下工程中的岩石爆炸风险.
科学领域:
- 地质技术工程 地质技术工程
- 岩石机械 岩石机械
- 材料科学 材料科学 材料科学
背景情况:
- 在深层地下工程中,联合岩石质量在长期压力下易受岩石爆发的影响.
- 现有的2D模型过于简化了3D断裂机制,无法捕捉复杂的混合模式断裂.
- 了解爬行下的3D断裂行为对于地下稳定性至关重要.
研究的目的:
- 在I/II/III混合模式断裂条件下,研究岩石质量与交叉关节的爬行失败行为.
- 分析关节交叉角度对岩石机械性能和故障模式的影响.
- 开发一种特征变量,用于关节性岩石群中的爬行损害演变.
主要方法:
- 使用了新的预制砂岩标本,其接头交叉 (0°/0°, 0°/30°, 0°/60°, 0°/90°).
- 进行了单轴压缩和多阶段爬行测试.
- 分析故障行为使用声辐射 (AE) 参数,如升高角度 (RA) 和平均频率 (AF).
主要成果:
- 单轴压力强度和弹性模量随着交叉关节的增加而下降.
- 爬行阶段显示最小的AE事件和轴向应变,直到第三阶段,出现急剧增加.
- 0°/60°标本表现出加速的爬行失效与X形拉伸剪切破裂;较大的角度增加了最终失效强度.
- 高的RA和AF值量化了爬行裂,对0°/0°,0°/30°和0°/90°标本的AF更高.
结论:
- 较大的关节交叉角度增强了相互约束和裂传播,增加了岩石质量的强度.
- 基于AE计数的新特征变量 (D) 有效地描述了爬行损伤的演变.
- 这些发现有助于更好地了解混合模式断裂爬行和微力学,有助于减轻岩石爆裂风险.
相关概念视频
01:28Factors Affecting Creep
134
In normal-weight aggregate concrete, the hardened cement paste is the primary contributor to creep, whereas the aggregates, being stiffer than the cement paste, are more resilient to stress-induced deformation. The stiffness of the aggregates is defined by their modulus of elasticity, and the more voluminous they are in the concrete, the less it will creep.
Further, the water/cement ratio is critical, as a lower ratio increases concrete strength, thus reducing creep. The strength of the...
Further, the water/cement ratio is critical, as a lower ratio increases concrete strength, thus reducing creep. The strength of the...
134
01:22Creep in Concrete
223
Creep refers to the time-dependent increase in strain under a sustained load, excluding other time-dependent deformations associated with shrinkage, swelling, and thermal expansion in concrete. The primary mechanism behind creep involves the loss of physically adsorbed water from the calcium silicate hydrate within the hydrated cement paste. This process is further exacerbated by concrete's non-linear stress-strain relationship, microcrack development in the interfacial transition zone, and...
223
01:23Behavior of Concrete Under Compressive Load
158
Concrete exhibits specific behaviors under different compressive loads. Understanding this is crucial for understanding its structural integrity. When concrete undergoes uniaxial compression, it tends to develop cracks that run parallel to the direction of the force. These parallel cracks stem from localized tensile stresses that occur perpendicular to the compression direction. Additionally, angled cracks may appear due to the formation of shear planes.
As the concrete specimen fractures under...
As the concrete specimen fractures under...
158
01:25Effects of Creep
136
Creep in concrete, the gradual deformation under prolonged stress, significantly impacts the integrity of structures. For reinforced concrete beams, it can be a vital design consideration, as it increases deflection, sometimes necessitating additional design measures. In columns, especially slender ones under eccentric loads, creep can cause buckling, compromising their stability. However, creep can be beneficial in indeterminate structures by mitigating stresses that arise from shrinkage,...
136
01:23Stresses under Combined Loadings
150
When analyzing a bent tube with a circular cross-section subjected to multiple forces, it is crucial to determine the stress distribution in order to maintain structural integrity under varied load conditions.
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
The process begins by slicing the tube at critical points and analyzing the internal forces and stress components at these sections, focusing on the centroid. Normal stresses, generated by axial forces and bending moments, are either compressive or tensile and vary across the section from...
150
01:16Dynamic Modulus of Elasticity of Concrete
315
The dynamic modulus of elasticity assesses how a concrete structure deforms under impact or dynamic loads. It is typically higher than the static modulus of elasticity, measured under slow, steady loading conditions.
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by...
The sonic test is a common method to determine the dynamic modulus. In this test, a concrete beam, sized either 6 x 6 x 30 inches or 4 x 4 x 20 inches, is clamped at its center. Vibrations are initiated at one end of the beam by an electromagnetic exciter unit powered by...
315