注水钻孔周围煤体径向位移数值模拟

Numerical simulation on radial displacement around coal seam water injection drilling

为揭示钻孔注水过程中煤体位移的发展和分布规律,基于COMSOL Multiphysics 4.3b2D建立煤层注水三场耦合模型,模拟不同注水压力和时间作用下钻孔周围煤体径向位移的变化规律.研究结果表明:随着注水时间的延长或注水压力的升高,煤体的位移量增大;钻孔两侧出现两个以纵向为长轴的椭圆形较大位移区,呈现"哑铃形"非均匀分布;"哑铃形"两端椭圆形的中心是位移最大的区域,随注水过程的延续最大位移带向远离钻孔方向发展,椭圆的长短轴随注水时间的延续和压力的提高逐渐变大.

In order to reveal the development and distribution law of coal body displacement during coal seam water flooding, this paper establish a simulation model coupled of solid mechanics-material, transmission and diffusion in porous, Darcy law by using software of COMSOL Multiphysics 4.3b2D, and studied the radial displacement around coal seam water injection drilling under different pressure and time of water injection. The results show that the radial displacement of coal body increases as the pressure and time of water injection increase; there are two larger displacement ellipses on the both sides of drilling, and the vertical axis is the major axis of ellipse with dumbbell-shape non-uniform distribution; the centers of the two ellipses are the largest displacement area, they are moving away from the drilling with extended water infusion, and the major and minor axes are longer with the pressure and time of water injection increase.