Study on Seepage Simulation of High Pressure Grouting in Microfractured Rock Mass

Abstract

In coal mines, under high in situ stress and strong mining activity, roadway surrounding rock commonly contains large amounts of larger fractures and microfractures. Along with the large deformation and continuous rheology of the soft rock roadway, the fractures in the surrounding rock are likely to be compressed and closed, forming undeveloped microfractures, which hinder conventional grouting support methods. Based on the fluid-solid coupling between slurry seepage and microfracture deformation, a theoretical model of microfracture grouting seepage is established. A program for the analysis and calculation of microfracture grouting is developed to quantitatively describe the variation in slurry seepage distance and fracture opening. Numerical experiments are carried out to study the grouting seepage of microfractures under different grouting pressures and fracture opening conditions, and the variation rules for the spatial distribution of fracture opening and slurry seepage distance during grouting pressure are obtained. Fluid-solid coupling has a significant influence on grout seepage characteristics. The grouting pressure and the fracture opening changes are nonlinearly attenuated along the grout seepage direction.

Analytical Solution of the Grouting Reinforcement Response of a Circular Cavern in Deeply Buried Fractured Surrounding Rock under a Nonuniform Stress Field

“…For example, certain scholars have systematically analyzed the grouting effect through numerical analysis. This approach makes the migration of grouting in the ideal state more intuitive and reveals that grouting can change the permeability and porosity of rock, change the crack and pore size distribution of rock, and also improve the compactness and strength of fractured rock. − Other scholars considered the theoretical basis of fluid mechanics and the distribution state of cracks and established analytical formulas such as grouting diffusion range and diffusion speed. − To evaluate the rock strength after grouting, Zhang et al established a preliminary theoretical model and an empirical formula for rock strength after grouting, which enabled prediction of the rock strength after grouting. In summary, scholars worldwide mainly use theoretical analysis, experimental analysis, and numerical simulation to evaluate the slurry diffusion and the effect of rock mass reinforcement, which greatly enriches and develops grouting theory.…”

Numerical Study of Percolation and Seepage Behaviors in Ion‐Adsorption‐Type Rare Earth Ore Leaching Process

“…Zhao et al [5] used Fluent software to simulate the migration of the water phase in three diferent flling structures under diferent initial water velocities and dynamic viscosities and indicated between the fxed particles (soil skeleton) in the flling structure, the looser structure, and the greater infuence of gravity on the water phase seepage. Wang et al [6] study the grouting seepage of microfractures under diferent grouting pressures and fracture opening conditions, and the grouting pressure and fracture opening changes are nonlinearly attenuated along the grout seepage direction. Li et al [7] examined the efects of particle size on fow regimes and the validity of Darcy law in the seepage process.…”

Simulation test study on filling flow law of gangue slurry in goaf

“…By establishing numerical models, Wang et al 32 studied the diffusion and rock displacement laws of fluidized gangue with different grouting speeds, pore ratios, and gangue particle sizes. Wang et al 33 studied the grouting seepage of micro-cracks under different grouting pressure and crack opening conditions through numerical experiments, and obtained the change law of the spatial distribution of crack opening and the change law of slurry seepage distance under grouting pressure. Wang et al 34 , 35 established a single crack grouting model considering fluid-structure coupling, and carried out numerical simulation research on the multi-physical coupling mechanism.…”