Strain-based non-Darcy permeability properties in crushed rock accompanying mass loss

To analyze the strain-based non-Darcy permeability properties in crushed rock accompanying mass loss, a self-designed seepage testing system for crushed rock accompanying mass loss is adopted. Based on the collected lost mass and time series of seepage velocity and the pressure gradient, permeability parameters and strain are obtained. Time-dependent characteristics of permeability parameters and strain are divided into three stages. Permeability and strain increase while non-Darcy flow β factor and acceleration coefficient decrease with seepage process lasting. Exponential functions between permeability parameters and strain are established, where strain is the volumetric strain, being in good agreement with conclusions drawn by scholars before. The coefficients of exponential functions are analyzed combining with the lost mass ratio. It shows that a greater mass loss leads to a larger permeability, inducing the greater possibility of water inrush; samples with the lost mass ratio less than 5% have the least water inrush possibility.