Influence of time-dependence on failure of echelon rock joints through a novel DEM model

Abstract

This article investigates the time-dependent influence on the shear failure behaviour of parallel rock joints in the echelon arrangement due to chemical weathering, which can be treated as a generalised time-dependency of the rock material. A time-dependent parameter α, identifying the accumulated relative mass removal of bonding material, has been implemented into a novel distinct element method bond contact model. This model is based on a series of mechanical test on bonded aluminium rods with different bond geometries. The numerical direct shear test results of echelon rock joints characterised by different values of α show that increasing time-dependent parameter α can lead to a lower crack initiation and peak stresses. This is accompanied by a growing ratio of the microscopic compressive–shear–torsional (CST) bond failure number of bond failures to the total number of failures, except for the case without weathering influence. High values of α render the material bridge a weaker part to be cut through, generating a large number of CST bond breakages along the central shear axis.

Keywords:

• time-dependency
• rock joints
• DEM
• chemical weathering

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is funded by the Major Project of Chinese National Programs for Fundamental Research and Development (973 Program) [grant number 2011CB013504], [grant number 2014CB046901]; China National Funds for Distinguished Young Scientists [grant number 51025932]; State Key Lab. of Disaster Reduction in Civil Engineering [grant number SLDRCE14-A-04].