Research and application of ground grouting water plugging technology in water filled goaf of steeply inclined thin coal seam in Southwest China
In order to study the control of the relevant coal mine goaf on the south bank of the water storage area of Jinsha Hydropower Station,the curtain grouting water plugging was selected as the control scheme.Through drilling,the cement slurry was filled into the goaf and its upper cracks,and the runoff channel between the Jinsha River and the mine was cut off.The curtain hole grouting adopted the cement-water glass double liquid slurry grouting process,and the general grouting hole adopted the cement slurry single liquid grouting process.In the results of the indoor setting time test,the final setting time of the cement slurry gradually decreased from more than 500 s to about 20 s with the increase of the water-cement ratio.According to the test results,the appropriate cement slurry ratio was determined.The average unconfined compressive strength of the four groups of cement cores in the goaf was 1.21 MPa,1.21 MPa,1.36 MPa and 1.29 MPa,respectively,and the wave velocity of the grouting section was 365 m/s-384 m/s.The compressive strength was greater than 1 MPa,and the shear wave velocity was greater than 350 m/s,indicating that the quality evaluation results after the implementation of the grouting and water plugging process met the requirements as a whole,which was feasible and practical.
steeply inclined thin coal seamwater-filled goafground grouting water pluggingcurtain grouting
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