Coastal karst cement-based expanding grouting material and preparation method therefor

A coastal karst cement-based expanding grouting material, wherein the expanding grouting material is composed of components A and B;

• the component A comprises a cementing material with volcanic ash characteristics, water and an expanding agent of 0.01-6.0%;
• the component B comprises the following components in weight percentages:
• 0.2-1.3% of a water-soluble vegetable gum, 0.5-2.0% of polyacrylamide, 0.01-2.0% of a polyacrylic acid derivative salt, 0.02-1.5% of a complexing agent, 0.05-1.5% of polyhydroxy polysaccharides, 2-70% of water glass and 42.3-90.3% of water;
• the expanding agent is prepared into a solution and from the following components in mass percentages:
• 0.01-0.05% of a polyacrylate derivative, 0.02-0.05% of sodium dodecyl sulfonate, 0.02-0.05% of sodium dodecyl sulfate, 0.02-0.05% of aluminum dodecyl sulfate, 0.03-1.5% of α-alkenyl sodium sulfonate and 0-0.6% of aluminum powder;
• the complexing agent comprises one or more of polyaluminium chloride, polyferric chloride, polyaluminium silicate, polyferric silicate, sodium citrate and sodium hexametaphosphate;
• the volume ratio of the component A to the component B is (0.5-5):1;
• when the content of ions in flowing water C(SO42−) is ≥0.8 g/L and C(Cl−) is ≥5.3 g/L, the size of a karst cavity is greater than 1 m*1 m*1 m, and the flow velocity of the flowing water is greater than 0.5 mls, the water-to-cementing material ratio in the component A is lower than 0.9 and the mixing amount of each auxiliary material of the component B is increased;
• and when the content of the ions in the flowing water C(SO42−) is ≤0.8 g/L and C(Cl−) is ≤5.3 g/L, the size of the karst cavity is smaller than 0.5 m*0.5 m*0.5 m, and the flow velocity of the flowing water is smaller than 0.5 mls, the water-to-cementing material ratio in the component A is selected to be 1.0 and the mixing amount of each auxiliary material of the component B is decreased;
• and
• the polyhydroxy polysaccharides comprises one or two of polyethylene glycol-2000, sodium gluconate, sodium alginate and curdlan.