Enhancing mine groundwater system prediction: Full-process simulation of mining-induced spatio-temporal variations in hydraulic conductivities via modularized modeling
Shihao Meng, Qiang Wu, Yifan Zeng, L. M. Gu
Abstract
• Developed a constitutive model for time-dependent permeability of overburden strata during mining. • Investigated the spatio-temporal evolution of overburden permeability. • Developed variable-parameter groundwater simulation technology for full mining process. The intricate interplay between rock mechanics and fracture-induced fluid flow during resource extraction exerts profound effects on groundwater systems, posing a pivotal challenge for promoting green and safe development in underground engineering. To address this, a novel numerical model with an explicit coupling simulation strategy is presented. This model integrates distinct modules for individual physical mechanisms, ensuring second-order accuracy through shared time integration, thereby overcoming limitations in simulating mining-induced strata damage, water flow, and permeability dynamics. A novel mathematical model is incorporated into the mechanical simulation to characterize the abrupt increase in permeability resulting from rock fracture propagation. This increase is quantified by evaluating the plastic damage state of rocks and incorporating a damage coefficient that is intrinsically linked to rock strength. The mechanical model tracks permeability changes due to mining. The flow model simulates aquifer-mine water interactions by calculating hydraulic conductivity and using dynamic zoning, adapting to mining progress. When applied to a case study of a complex mine, this approach significantly improved the accuracy of water inflow rate predictions by 57%.