在直接剪切下对花岩和大理石岩桥的渐进性故障进行比较研究
Guangming Luo1,2,3, Shengwen Qi4,5,6, Bowen Zheng1,2,3
1Key Laboratory of Shale Gas and Geoengineering, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China.
Scientific reports
|May 13, 2024
概括
这项研究研究了采用直接剪切实验和声辐射监测的岩桥剪切故障. 发现揭示了正常应力和岩石类型影响的明显的破裂前阶段,这对于理解像山体滑坡这样的地质事件至关重要.
科学领域:
- 地质技术工程 地质技术工程
- 岩石机械学 岩石机械学
- 地震学 地震学
背景情况:
- 岩石桥梁的剪切故障在地质过程中至关重要,如山体滑坡和地震.
- 天然岩石桥梁的渐进性故障机制仍然不完全理解.
研究的目的:
- 为了研究在直接剪切下花岩和大理石岩石桥梁的渐进性故障.
- 分析正常应力和石质学对岩桥故障阶段的影响,使用声学排放数据.
主要方法:
- 在花岩和大理石岩桥上进行了直接剪切实验.
- 使用声波排放 (AE) 监测来追踪剪切过程中的微碎裂.
- 分析了机械曲线和AE参数 (能量率,b值).
主要成果:
- 岩桥故障的特点是三个预故障和一个最终故障阶段.
- 增加的正常应力减少了稳定的裂变阶段,稍微增加了不稳定的阶段.
- 大理石在高正常应力下表现出长期稳定的裂变阶段,这归因于断层外损伤.
- 正常的应力对花岩和大理石的膨胀有不同的影响,突出了岩石学影响.
结论:
- 该研究成功地根据机械和AE数据将岩桥故障分为不同的阶段.
- 正常的应力和石质学显著调节岩桥剪切故障的进展和特征.
- 结果提供了对地质危险评估相关的复杂故障机制的见解.
相关概念视频
Stress-Strain Diagram - Brittle Materials
2.3K
Brittle materials, including glass, cast iron, and stone, exhibit unique characteristics. They fracture without considerable change in their elongation rate, indicating that their breaking and ultimate strength are equivalent. Such materials also show lower strain levels at the point of rupture. The failure in brittle materials predominantly results from normal stresses, as evidenced by the rupture created along a surface perpendicular to the applied load. These materials do not display...
2.3K
Behavior 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
Microcracking in Concrete
117
Microcracking in concrete refers to the tiny cracks that can form within the material even before any external load is applied. These microcracks typically occur at the interface between the coarse aggregate and the hydrated cement paste, often as a result of differential volume changes prompted by variations in stress-strain behavior, as well as thermal and moisture movement. Initially, these microcracks remain stable and do not grow substantially until the concrete is stressed to about 30...
117
Tensile Strength Considerations of Concrete
126
Considering the tensile strength of concrete involves recognizing that the theoretical strength of cement paste can be up to a thousand times higher than what is observed in practical applications. This significant discrepancy is largely attributed to the presence of microscopic cracks within the concrete. These cracks tend to amplify stress at their tips when a load is applied, a phenomenon explained by Griffith's theory of brittle fracture.
The dimensions and shape of a concrete specimen...
The dimensions and shape of a concrete specimen...
126
Shearing Stresses in a Beam: Problem Solving
185
A cantilever beam with a rectangular cross-section under distributed and point loads experiences shearing stresses. The analysis begins by identifying the loads acting on the beam. Then, the reactions at the beam's fixed end are calculated using equilibrium equations. The vertical reaction is a combination of the distributed and point loads, while the moment reaction is the sum of their moments. The shear force distribution along the beam, resulting from these loads, is established by...
185
Shearing Strain
263
The shearing strain represents a cubic element's angular change when subjected to shearing stress. This type of stress can transform a cube into an oblique parallelepiped without influencing normal strains. The cubic element experiences a significant transformation when exposed solely to shearing stress. Its shape alters from a perfect cube into a rhomboid, clearly demonstrating the effect of shearing strain. The degree of this strain is considered positive if it reduces the angle between...
263


