基于压水试验和放水恢复试验的帷幕注浆效果综合评价

Comprehensive Evaluation of Curtain Grouting Effect Based on Water Pressure Test and Dewatering Test

帷幕注浆效果评价是烧变岩水害治理工程的重要环节之一。以神南矿区柠条塔煤矿S1232工作面烧变岩水害帷幕注浆工程为背景,分别采用检查孔取心验证、注浆前后压水试验、抽水试验以及井下放水试验恢复试验对治理工程的效果进行综合评价。结果表明:通过取心发现在风化基岩段均见到水泥浆液充填薄层,J5孔在烧变岩烘烤岩层中发现浆液填充。注浆后续孔的渗透系数在1.8×10^(-5)~5.9×10^(-5)cm/s,5个检查孔中的渗透系数为2.2×10^(-5)~3.7×10^(-5)cm/s,注浆后的抽水孔渗透系数在2.7×10^(-5)~4.3×10^(-5)cm/s,均属于弱透水。对比注浆前的渗透系数,注浆后的所有钻孔压水试验获得的地层渗透系数均减少了一个数量级。根据抽水实验结果,注浆前后的渗透系数为190×10^(-6)cm/s和(1.04~2.2)×10^(-6)cm/s,单位涌水量分别为0.045 9L/(s·m)和0.014 1~0.023 1L/(s·m)。注浆后帷幕区域渗透系数远小于注浆前,相差两个数量级,单位涌水量数值也减小了一半。根据注浆前后放水恢复实验结果,注浆后井下关水水位恢复均较注浆前快。F26孔初始水压0.8MPa,注浆前后分别在关水后4h和5.55h后水压恢复至0.6MPa;地面长观孔的水位变化也呈现相同的趋势。以上所有指标均反映了帷幕注浆工程对火烧区改造明显,和南侧烧变岩含水层的水力联系明显降低,帷幕注浆效果明显。研究成果将为类似条件的烧变岩水害治理工程效果评价提供参考。

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^(-5)cm/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^(-6)cm/s and(1.04~2.2)×10^(-6)cm/s,with a unit water inflow of 0.0459L/(s•m)and 0.0141~0.0231L/(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.