Analysis of coalescence mechanism of coplanar intermittent flaws
under static and dynamic loading |
| |
| Authors: | ZHANG Ping LI Ning Li Xi-bing |
| |
| Institution: | 1. School of Resources and Safety Engineering, Central South University, Changsha 410083, China; 2. College of Civil Engineering, Hunan University, Changsha 410082, China; 3. Institute of Geotechnical Engineering, Xi’an University of Technology, Xi’an 710048, China |
| |
| Abstract: | The coalescence mechanism of coplanar intermittent flaws under static and dynamic loading is important in determining the position and shear strength of sliding face of rock slope. The process of the fracture propagation and coalescence between two coplanar intermittent flaws is studied under uniaxial static and dynamic loading. The specimens made of sandstone-like modeling material contain two pre-existing coplanar flaws with different flaw angles from 0o to 90o. The result indicates that the coalescence modes are different for different flaw angles. When the flaw angles are between 0o and 35o, the flaw surfaces produce close deformation mostly; when the flaw angles are between 45o and 65o, the fractures coalesce in shear modes; when the flaw angles are between 75o and 90o, the splitting failures are prone to appear. Moreover, the growth of the wing fracture and secondary co-planar fracture tends to the original propagation direction, and the immediate coalescence is taken place easily between two pre-existing flaws. But the fracture coalescence path is winding under static loading, which is different from dynamic loading. Additionally, the lowest strength is observed when the flaw angle is 35o for specimens containing intermittent flaws, which is different from specimens containing persistent flaws whose lowest strength is observed at 60o. The reason is that the strength of fracture surface is not mobilized when the specimen fails. Because the rock bridge’s strength and fracture surface’s friction can’t be mobilized simultaneously, the shear strength formula for rock mass containing intermittent flaws should introduce a strength mobilization factor. |
| |
| Keywords: | dynamic loading coplanar intermittent flaws coalescence mechanism shear strength |
|
| 点击此处可从《岩土力学》浏览原始摘要信息 |
| 点击此处可从《岩土力学》下载免费的PDF全文 |
|
