矿区岩溶裂隙岩体帷幕截流注浆参数确定研究

Study on determination of curtain closure grouting parameters of fractured rock mass in karst mining area

为使用帷幕注浆手段治理某矿区岩溶裂隙发育地层水害,采用室内试验对不同水灰比水泥浆液性能进行试验研究,得到不同水灰比水泥浆液性能及变化规律;并利用理论分析和数值计算对帷幕注浆压力和水泥浆液扩散半径进行了研究计算;结合帷幕墙体建设区域水文地质条件,综合确定了帷幕墙体建造尺寸、钻孔间距、注浆压力及水泥浆液选取工艺,为帷幕注浆治理工程设计提供了科学依据。最后,利用帷幕墙体内外放水试验检验了帷幕注浆墙体的截流效果,截流效果达到设计目的和要求,因此也验证了帷幕注浆参数选择的合理性。研究结果表明:水泥浆液黏度、结石率和结石体强度随水固的增大而降低,凝结时间随着水灰比的增大而增大,变化速率随水灰比的增大而降低;帷幕墙体厚度为40m、钻孔间距为20m和注浆终孔压力为4~6MPa;利用放水试验对比帷幕墙体内外水位变化历时曲线是帷幕注浆效果检验的最直接手段。

In order to use curtain grouting to control the formation water damage of karst fissures in mining area, experimental tests were carried out the performance of cement slurries with different water-cement ratios,and the performance and variation of cement slurries with different water-cement ratios were obtained.The curtain grouting pressure and the diffusion radius of cement slurry were studied and calculated by theoretical analysis and numerical calculation.Combined with the hydro-geological conditions of the curtain wall construction area,the construction dimensions of the curtain wall,borehole spacing,grouting pressure and cement slurry selection process were determined comprehensively,which provided a scientific basis for curtain grouting control engineering design.Finally,the closure effect of curtain grouting wall was tested by water release test inside and outside the curtain wall.The closure effect achieved the design purpose and requirements.Therefore,the rationality of the selection of curtain grouting parameters was also verified.The results show that the cement slurry viscosity,stone rate and stone strength decrease with the increase of water-solid ratio,the setting time increases with the increase of water-solid ratio,and the rate of change decreases with the increase of water-cement ratio;the curtain wall thickness is 40 m,the borehole spacing is 20 m and the grouting end hole pressure is 4~6 MPa;the curtain grouting is used to compare the water level change curve inside and outside the curtain wall by water release test.It is by far the most direct means of curtain grouting effect test.