An Experimental Investigation for Seepage-Induced Instability of Confined Broken Mudstones with Consideration of Mass Loss

Abstract

To study and prevent water-mud-outburst disasters of tectonic fracture zones in geotechnical engineering, we tested seepage stability of confined broken mudstones with consideration of mass loss using syringe seepage method and a self-designed seepage testing system, obtained the variation laws of seepage instable duration, total mass loss, and mass loss rate of broken mudstones under different pressure gradients and Talbol power exponents (simplified as Talbol hereafter), and explained their instable seepage behaviors. The results showed that the mass loss is the internal cause of seepage-induced instability of broken rocks and pressure gradient is the external cause, and the persistent migration and loss of particles result in progressive failure process, while the large enough pressure gradient causes sudden overall instability. The seepage instable duration shortens with pressure gradient increasing, with the longest and shortest duration at Talbol of 0.5 and 0.1, respectively. In general, mass loss increases with pressure gradient increasing and with Talbol decreasing. Mass loss rate increases with pressure gradient increasing but shows no monotonic changes with Talbol. Their expressions can be used to establish dynamic model in the further seepage stability researches.

A Water-Rock Coupled Model for Fault Water Inrush: A Case Study in Xiaochang Coal Mine, China

“…Moreover, the relationship between the permeability coe cient and axial stress was nonlinear, so an exponential function (equation (4)) was used to describe the nonlinear relationship. e other study results show that permeability parameter k of crushed rock has a polynomial relationship with e ective stress σ ′ in inverse proportion [23,25,26,28,31,32].…”

“…e Darcy law explains the flow of water in rocks with regards to the effect of rocks on water, and since then, other scholars have conducted numerous studies on the relationships among the pore pressure (pp), permeability coefficient, and strain and stress [13,17,19,20]. In addition, numerous simulation studies have been performed to address water inrush issues [4,15,[21][22][23][24]. However, these studies regarded the fault only as a discrete face, thereby neglecting the fault fracture zone and the water-rock coupling effect.…”

The variation of grain size distribution in rock granular material in seepage process considering the mechanical–hydrological–chemical coupling effect: an experimental research

“…In geotechnical engineering, water often coexists with the rock granular materials. Water flows in the gaps and spaces of the rock granular materials [32], scours and erodes them, makes some of the rock granular materials re-break and produces secondary rock grains [33], drives particles to migrate and loss through the gaps and spaces [34][35][36][37][38][39], which varies the porosity [40,41], local stress [41] and seepage fields [40,[42][43][44][45][46][47][48][49]. As the rock grains' migration and loss continues, porosity increases and permeability grows until mutation, resulting in seepage instability and even seepage catastrophe.…”

Variation Characteristics of Mass-Loss Rate in Dynamic Seepage System of the Broken Rocks

“…These studies found that the migration and loss of mobile fine particles were affected by many factors, such as seepage type [16,18,[24][25][26]28], particle size graduation [19, 21-23, 27, 29-32], seepage velocity [20], and pore water pressure [17,[32][33][34]. However, they did not consider the porous structure inside the framework particles, the changes concurring with the migration and dissipation of fine particles, and the effect of time-varying porosity on fine particle loss.…”