Expansive polymer grouting material for treating high-pressure large-flow-rate karst water inrush and preparation method thereof

A preparation method of an expansive polymer grouting material for treating high-pressure large-flow-rate karst water inrush, comprising the following steps:

• (1) adding a crosslinking agent to acrylic acid;
• then adding a polymer water-absorbent resin comonomer and performing a polymerization reaction to obtain a precursor;
• (2) adding an initiator to the precursor of step (1), heating the mixture, performing a reaction to obtain a hydrogel, and grinding the hydrogel to obtain a primary polymer water-absorbent resin;
• (3) spraying a surface crosslinking agent onto a surface of the primary polymer water-absorbent resin of step (2), and drying the obtained product for later use;
• and
• (4) preparing a suspension from an inorganic water conducting agent, spraying the suspension onto the dried product of step (3), and performing drying to obtain the expansive polymer grouting material;
• wherein the polymer water-absorbent resin comonomer comprises polyvinyl alcohol, acrylamide, methacrylamide or acrylonitrile;
• the crosslinking agent comprises one or a combination of more of N,N-methylenebisacrylamide, dipentaerythritol hexaacrylate, pentaerythritol tetraester, pentaerythritol triallyl ether, pentaerythritol triacrylate, polyethylene glycol diglycidyl ether, ethoxylated glycerol triacrylate and ethylene glycol dimethacrylate;
• the surface crosslinking agent comprises one or a combination of more of water, polylol, glycidyl ether, ethylene carbonate, propylene carbonate and a polyvalent metal compound;
• and
• the inorganic water conducting agent comprises fumed silica, nano titania or activated alumina powder.