Swelling Pressure of Double-Expansive Material and Its Active Support Effect for Coal Seam Gas Drainage Borehole

Figure 2

The micrographs of the DE material and the EDS of the CH and Aft crystals: (a) micrograph at the 16th hour; (b) micrograph at the 168th hour; (c) EDS of CH crystal; (d) EDS of AFt crystal.

(a)

(b)

(c)

(d)