The flow resistance of CDG in the fine and coarse sandpacks increased rapidly, after the solutions corresponding 21 and 65 times of porous volume were injected respectively.

• CDG体系在粗砂中流动时，需流过65Vp（孔隙体积）的溶液，才能使填充砂管的阻力系数大大增加； 而要增加同样的阻力系数，细砂管只需流过21Vp的溶液。