西南地区急倾斜薄煤层充水采空区地面注浆堵水工艺研究及应用

Research and application of ground grouting water plugging technology in water filled goaf of steeply inclined thin coal seam in Southwest China

针对金沙水电站蓄水区南岸的相关煤矿采空区的治理,选择帷幕注浆堵水为治理方案。通过钻孔将水泥浆充填采空区及其上部裂隙,切断金沙江与矿井之间的径流通道,其中帷幕孔注浆采用水泥-水玻璃双液浆注浆工艺,一般注浆孔采用水泥浆单液注浆工艺。室内凝结时间检测试验的结果中,水泥浆的终凝时间随着水灰比的增大而逐渐从500 s以上下降到20 s左右,根据试验结果确定了合适的水泥浆配比。注浆堵水质量检测得到4组水泥芯体的采空区无侧限抗压强度均值分别为1.21、1.21、1.36、1.29 MPa,注浆段波速值为365~384m/s。抗压强度大于1 MPa,横波波速大于350 m/s,表明注浆堵水工艺实施后的质量评价结果整体满足要求,具有可行性与实用性。

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.