疏水降压是煤矿顶板水害防治的主要工程手段，复合充水含水层中倾斜疏放水钻孔涌水量计算及参数优化是需要解决的关键技术。以“渗流-管流耦合模型”理论及能量守恒定律为基础，以含水层-钻孔间水量交换量为耦合点，构建了煤层顶板复合充水含水层倾斜疏放水钻孔定降深放水的含水层-钻孔系统耦合模型，利用母杜柴登矿井临时煤仓放水试验数据验证了模型的可靠性。以此为基础，计算了不同钻孔仰角、数量的钻孔涌水量及单位长度涌水量，确定了钻孔的最佳仰角和数量。同时，计算分析了150 m钻场间距下600 m工作面范围内不同疏降水头的钻孔涌水量、工作面内部降深的特征。结果表明:基于含水层-钻孔水量交换的疏放水钻孔水量计算模型充分考虑了疏放水过程中钻孔内的层流和紊流水流特征。模型计算的1个主放水孔水量和2个观测孔水位历时变化和现场实际情况基本一致，模型可靠性好，且能解决倾斜钻孔在复合充水含水层中的水量分配问题。随着疏放水钻孔仰角的增大，单位长度的钻孔涌水量呈现先增加后减小的趋势，在仰角为60°时，钻孔单位涌水量最大，稳定水量为165 m³/h，主要涌水层位为直罗组一段含水层，约占总涌水量的81%。此外，随着钻孔数量增加，单个钻场内钻孔总涌水量不断增加，单位长度的钻孔涌水量呈现逐步减小的趋势，钻孔数量增至5个后总涌水量基本稳定，钻孔稳定总涌水量约为440 m³/h。在150 m钻场间距下600 m工作面范围中，60 d内，780 m定水头疏降时，钻孔总涌水量由1 700 m³/h降至170 m³/h，降幅达90%;830和880 m定水头疏降下，钻孔总涌水量由1 530，1 350 m³/h分别降至153，135 m³/h，降幅均为90%。钻场内钻孔总涌水量受到周边钻场疏降干扰的影响，由两端向内侧影响逐步增大。780 m定水头疏降时，两端钻孔总涌水量约为309 m³/h，最中间钻场钻孔总涌水量约为142 m³/h。工作面内部水头分别降至780,830和880 m的时间分别为155,125和100 d。随着时间推移，不同降深范围逐步增大。随着疏放时间的延续，横剖面呈现以倾斜钻孔为中心的降落漏斗且范围逐步扩大，平面上则呈现以全部钻场范围为中心的降落漏斗且范围逐渐增大。

Depressurization by dewatering is a main engineering method for the prevention and control of roof water disaster in coal mines.The calculation of water yield and parameter optimization of inclined drainage boreholes in the compound water filled aquifers is a key technology to be developed.Based on the theory of coupled model of seepage and pipe flow,the law of energy conservation,taking the water exchange between aquifer and borehole as the coupling point,a coupling model of aquifer borehole system was established for the inclined drainage boreholes of coal seam roof compound water-filled aquifer and the reliability of the model was verified by the data from the dewatering test of the temporary coal bunker in Muduchaideng coal mine.Based on this model,the water yield of different elevation angles,number and the water yield per unit length were calculated,and the optimal elevation angles and number of boreholes were determined.Meanwhile,the characteristics of borehole water yield of different dewatering heads and the drawdown inside the working face in the range of 600 m working face under 150 m drilling field spacing were calculated and analyzed.The results showed that the calculation model of drainage boreholes water yield based on water exchange between aquifers and boreholes fully considered the laminar and turbulent flow characteristics in the borehole during drainage.The water yield of one main drainage hole and the water levels of two observation holes calculated by the model were consistent with the actual situation.The model had good reliability and could determine the proportion of aquifer water in inclined borehole in compound water filled aquifer.With the increase of elevation angle of drainage borehole,the water yield per unit length of borehole showed a trend of increasing first and then decreasing.When the elevation angle was 60°,the water yield per unit of borehole was the maximum,with a stable water yield of 165 m3/h and the main water yield layer was the first member of Zhiluo Formation,accounting for about 81% of the total water yield.In addition,with the increase of the number of boreholes in a single drilling field,the total water yield of boreholes increased continuously,and the water inflow of boreholes per unit length showed a gradually decreasing trend.After the number of boreholes reached 5,the total water yield was basically stable,and the stable total water yield of boreholes was about 440 m³/h.In the range of 600 m working face under 150 m drilling field spacing,within 60 days,the total water yield from the borehole decreased from 1 700 m³/h to 170 m³/h under the 780 m water head,a decrease of 90%,and decreased from 1 530 m³/h and 1 350 m³/h to 153 m³/h and 135 m³/h respectively,with a decrease of 90%,under the 830 m and 880 m constant water head.The total water yield from the drilling field was affected by the drainage of the surrounding drilling field and gradually increased from both ends to the inside.The total water yield from the boreholes at both ends was about 309 m3/h,and the total water yield from the boreholes in the middle drilling field was about 142 m³/h under the 780 m water head.The time of the working face water head drop to 780 m,830 m and 880 m was 150,125 and 100 d respectively.As time went on,the range of different depths gradually increased.In addition,with the extension of the drainage time,the cross section presented a descending funnel centered on the inclined borehole and its range gradually increased,while the plane presented a descending funnel centered on the whole drilling field and its range gradually increased.The study results can provide a reference for the optimal arrangement of pre drainage holes and the reasonable development of drainage project before coal seam mining.

1 基于含水层-钻孔水量交换的疏放钻孔水量计算模型

   1.1 含水层子系统渗流模型

   1.2 钻孔子系统管流模型

   1.3 含水层-钻孔系统耦合模型

2 模型可靠性验证

   2.1 研究区概况

   2.2 模型验证

3 钻孔参数优化

   3.1 角度

   3.2 数量

4 600 m工作面疏放水效果

   4.1 钻场涌水量

   4.2 降深

   4.3 流场

5 结论