Comprehensive Evaluation of Curtain Grouting Effect Based on Water Pressure Test and Dewatering Test
The evaluation of curtain grouting effect is one of the important links in the treatment of burnt rock water hazards.Taking the S1232 coal mine face of Ningtiaota coal mine in Shennan mining area as the background,a comprehensive evaluation of the effectiveness of the control project was conducted using inspection hole core verification,pre-and post grouting water pressure test,pumping test,and dewatering test.The results showed that a thin layer of cement slurry filling was found in the weathered bedrock section through core sampling,and slurry filling was found in the burnt rock layer of J5 hole.The permeability coefficient of the subsequent holes after grouting is 1.8×10-5～5.9×10-5 cm/s,permeability coefficient of 5 inspection holes is 2.2×10-5～3.7×10-5cm/s,the permeability coefficient of the pumping hole after grouting is 2.7×10-5～4.3×10-5 cm/s,and all belong to weak permeability.Compared with the permeability coefficient before grouting,the permeability coefficient of the formation obtained from all drilling water pressure tests after grouting has decreased by an order of magnitude.According to the pumping experiment results,the permeability coefficient before and after grouting is 190×10-6cm/s and(1.04～2.2)×10-6cm/s,with a unit water inflow of 0.0459L/(s·m)and 0.014 1～0.023 1L/(s·m),respectively.The permeability coefficient of the curtain area after grouting is much smaller than before grouting,with a difference of two orders of magnitude,and the unit water inflow value has also been reduced by half.According to the results of the water discharge recovery experiment before and after grouting,the water level at the bottom of the well recovered faster after grouting than before.The initial water pressure of F26 hole is 0.8MPa,and the water pressure recovers to 0.6MPa after 4 hours and 5.55 hours of water shut-off before and after grouting,respectively;The water level changes of the ground observation holes also show the same trend.All the above indicators reflect that the curtain grouting project has significantly improved the fire area and reduced the hydraulic connection with the southern burnt rock aquifer,resulting in a significant effect of curtain grouting.The research results will provide reference for the evaluation of the effectiveness of water damage control engineering for burnt rock under similar conditions.
prevention and control of mine water hazardscurtain grouting effectpermeability coefficientwater pressure recoverywater pressure testdewatering testNingtiaota coal mine
NETL
NSTL
万方数据
