Numerical Insight Into Energy Partitioning During Stick‐Slip Events Based on the Framework of Rate‐and‐State Friction Law

Abstract

Many attempts have been made to investigate the energy budgets of stick‐slip events, however, the strain energy contribution is still poorly understood. We developed a discrete element method (DEM)‐based method to mimic stick‐slip events and the associated energy partitioning. We found that stress drop Δσ, breakdown energy EG, and strain energy release ΔU scale with slip δc as normalΔσ0.25em∝δc1.1 ${\Delta}\sigma \,\propto {\delta }_{c}^{1.1}$, EG∝δc2.05 ${E}_{G}\propto {\delta }_{c}^{2.05}$, and normalΔU∝δc2.1 ${\Delta}U\propto {\delta }_{c}^{2.1}$, respectively, which is quantitatively consistent with data from manmade seismicity and natural earthquakes. We observed two different slip‐weakening behavior patterns: one without a postseismic phase (Type I) and one containing a postseismic phase (Type II). We show that ΔU contributes 20%∼90% (63% on average) and 10% ∼ 60% (38% on average) to the total energy budget for Type I and Type II events, respectively. Formations that store higher strain energy play a more vital role in the earthquake energy budget, regardless of the distance to the fault.

Fracture Mechanism of Coal Seams Induced by a Multibranched Borehole Drilling (MBBD) Technique to Enhance Coalbed Methane (CBM) Extraction

“…The bond’s macro strength depends on three microparameters: tensile strength (σ̅ t ), cohesion ( c ), and friction angle (ϕ). These parameters can be determined through conventional uniaxial compression tests in the simulation using a trail-and-error strategy, as discussed in detail in previous studies. − The numerical simulations of uniaxial compression, along with the optimization of microparameter combinations, ensure high consistency in the simulation of the deformation characteristics (elastic modulus, Poisson’s ratio) and strength properties (uniaxial compressive strength) of the coal sample. This consistency guarantees that the numerical model is convincing.…”