Sandaogou Coal Mine, Shanxi Deyuan Fugu Energy Co., Ltd.
CCTEG Chongqing Research Institute

为探究煤层注水时水在煤体中的渗流演化规律,采用实验室试验与数值模拟结合的方法,开展了地应力及孔隙水压力耦合作用下煤体结构变形及渗透率演化规律试验,并建立了水力耦合下体积变形演化数学模型,基于UDF二次开发进行了煤岩注水渗流动态演化数值模拟。研究结果表明:煤岩孔隙率变化受应力与水压共同作用的影响;煤岩轴向变形量与水压分布由上至下呈递减式传递,体积变形与轴向力、孔隙水压大小成正相关;孔隙水压为赋存于孔裂隙的自由水提供渗透动力,并对煤岩基质骨架产生力学作用,水压越大,煤岩基质骨架越容易破坏;采用UDF程序加载渗透性试验结果对孔隙率随孔隙水压变化进行拟合的结果更接近试验结果,误差较小,对于研究煤岩渗流规律可以提供一定的参考。

To elucidate the dynamics of water seepage within coal matrices during coal seam water injection, this research integrates laboratory experiments with numerical simulations. Experiments were conducted to examine the deformation of coal structures and the evolution of permeability under the dual effects of geostress and pore water pressure coupling. A mathematical model for the evolution of volume deformation under hydraulic coupling was formulated, followed by dynamic numerical simulations of water injection seepage in coal using secondary development with User-Defined Functions (UDF). The findings reveal that porosity changes in the coal rock are jointly influenced by stress and water pressure, with coal rock axial deformation and water pressure distribution showing a progressive decrease from top to bottom. Volume deformation correlates positively with axial load and the magnitude of pore water pressure. Pore water pressure acts as the driving force for the permeation of free wa-ter within pores and fractures, also affecting the coal matrix's mechanical integrity, with increased water pressure facilitating matrix damage. Utilizing UDF to fit the porosity changes against pore water pressure based on perme-ability test results yielded simulations closely aligned with experimental observations, demonstrating minimal discrepancies. This approach, leveraging Fluent for dynamic simulation of fluid-solid coupling experiments, of-fers valuable insights into the seepage behavior of coal.

吕明杰,刘立仁,张小涛,等.水力耦合作用下煤岩渗流动态演化规律[J].采矿与岩层控制工程学报,2024,6(2):023039.

LYU Mingjie, LIU Liren, ZHANG Xiaotao, et al. Dynamic evolution law of coal seepage under hydraulic coupling[J]. Journal of Mining and Strata Control Engineering, 2024, 6(2): 023039.