Influence of weak interlayer thickness on mechanical response and failure behavior of rock under true triaxial stress condition

Zhao，Honggang1,2,3; Deng，Bozhi1,2; Zhang，Dongming1,2; Li，Minghui1,2,4; Song，Zhenlong1,2,5

2024-08-01

10.1016/j.engfailanal.2024.108419

Engineering Failure Analysis   影响因子和分区

1350-6307

In this study, we meticulously investigate the influence of the thickness of weak interlayer on mechanical response and failure behavior of rock mass near the free surface of tunnel, with the aid of a true triaxial test system. We simulated the true triaxial stress condition of rock mass containing weak interlayer proximate to the excavation boundary, where one face remains free, while others are subjected to loading stress and increasing tangential stress. The experimental results reveal a distinct change in the fracture morphology near the free surface of rock mass as the thickness of weak interlayer increases, concomitant with a gradual decrease in the fractal dimension. With the increase of the thickness of weak interlayer, the failure characteristics of rock mass change from a “binary” to a “unitary” feature, i.e. mixed tension-shear failure near the free surface and shear failure far away from the free surface changes to mixed tension-shear failure that only occurs near the free surface. Moreover, an inverse relationship is observed between the bearing capacity of the rock mass and the thickness of weak interlayer. Conversely, the peak strain in the tangential stress direction increases with the increase of the thickness of weak interlayer, illustrating that the slip shear strain of rock block positioned above the weak interlayer is gradually formed, and governs the strain behavior of rock mass in the tangential stress direction with the increases of the thickness of weak interlayer. By employing the finite-discrete element method (FDEM), we replicated the failure process of surrounding rocks containing weak interlayers near the free surface of tunnel, demonstrating considerable congruity with our physical test results. In light of the failure characteristics of surrounding rocks containing weak interlayers, we advocated a localized area priority reinforcement support strategy, prioritizing regions with weak interlayers. Numerical simulations verified the effectiveness of this approach in controlling fracture proliferation in surrounding rocks and inhibiting the splitting failure of surrounding rocks containing weak interlayers near the free surface of tunnel.

Finite-discrete element method Mixed tension-shear failure Slip shear strain True triaxial Weak interlayer

SCI ; EI

英语

其他

20242016093870

Failure (mechanical) ; Fractal dimension ; Inverse problems ; Morphology ; Rock mechanics ; Rocks ; Stress analysis

Soils and Soil Mechanics:483.1 ; Mathematics:921 ; Mechanics:931.1 ; Physical Properties of Gases, Liquids and Solids:931.2 ; Materials Science:951

ENGINEERING

2-s2.0-85192737696

Scopus

1.State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing,400030,China
2.School of Resources and Safety Engineering,Chongqing University,Chongqing,400030,China
3.Chongqing Key Laboratory of Geomechanics & Geoenvironmental Protection,Department of Military Installations,Army Logistics Academy of PLA,Chongqing,401311,China
4.Institute of Deep Earth Sciences and Green Energy,College of Civil and Transportation Engineering,Shenzhen University,Shenzhen,518060,China
5.Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,518055,China

Zhao，Honggang,Deng，Bozhi,Zhang，Dongming,et al. Influence of weak interlayer thickness on mechanical response and failure behavior of rock under true triaxial stress condition[J]. Engineering Failure Analysis,2024,162.

Zhao，Honggang,Deng，Bozhi,Zhang，Dongming,Li，Minghui,&Song，Zhenlong.(2024).Influence of weak interlayer thickness on mechanical response and failure behavior of rock under true triaxial stress condition.Engineering Failure Analysis,162.

Zhao，Honggang,et al."Influence of weak interlayer thickness on mechanical response and failure behavior of rock under true triaxial stress condition".Engineering Failure Analysis 162(2024).