Treatment of Water Inrush in Mine Engineering Using a Superabsorbent Polymer: A Case Study of a Limestone Mine, Pingnan, China

Water inrush is a major geological hazard that threatens the safety of underground engineering projects. Grouting can effectively prevent and control such disasters. This article proposes a new type of super absorbent polymer (SAP) slurry grout and provides a method for its synthesis. The expansion ratio of the material in deionised water is as high as 320 times. We studied the effects of temperature and particle size on the viscosity and degree of segregation with glycerol as the carrier fluid. To ensure good pumping stability, the recommended slurry ratio is SAP: glycerol = 1/3, and the slurry temperature should be maintained at 35 °C. We carried out model tests using a karst-channel water-inrush simulation device. Notably, 217 kg of slurry successfully blocked a 1 m/s gushing flow that was 400 mm wide and 250 mm high. Water-plugging field tests were then conducted at typical flows. The flowing water in the karst channel was transformed into static water with the SAP slurry, and then an ordinary cement slurry was injected to strengthen the stratum. The model- and field-test results both showed the superior water-inrush blocking ability of the SAP slurry.