富水砂卵石地层冻结孔钻进泥浆配比优化研究

在富水砂卵石地层地铁联络通道近水平冻结孔钻进时，因泥浆黏度低，稳定性差，护壁及润滑作用弱造成泥浆损失及钻头磨损严重、塌孔、卡钻和断杆等问题。为了优化富水砂卵石地层下冻结孔钻进泥浆配比，通过单因素试验以及响应面分析法中的Box-Benhnken(中心组和)正交试验方法进行试验设计与数据分析，得出适用于富水砂卵石地层冻结孔钻进泥浆优化配比。基于北京地铁12号线的工程应用表明：采用优化泥浆配比，即膨润土含量为7.18%,水解聚丙烯酰胺含量为0.20%,钠羧甲基纤维素含量为0.19%,硫酸铝的含量为0.03%时，泥浆黏度提高32%,泥皮厚度增加了20%,滤失量减少了30%,润滑系数减少了60%,冻结孔钻进泥浆主要性能指标明显改善，冻结孔打钻时的减阻效果显著，钻杆所受轴力平均减少15%,所受扭矩平均减少13%,泥浆的膨润土用量和回流损失量减少了30%,材料成本明显降低，未发生塌孔、断杆和卡钻等工程事故，冻结孔钻进效率及成孔质量明显提高。

Development research and engineering application analysis of drilling mud in near-horizontal frozen holes under water-rich sand and pebble formations

When drilling near-horizontal frozen holes in subway connecting passages in water-rich sand and pebble formations, due to low mud viscosity, poor stability, weak wall protection and lubrication, mud loss, serious drill bit wear, hole collapse, stuck drill and broken rods and other problems . In order to optimize the drilling mud ratio of frozen holes in water-rich sand and pebble formations, the experimental design and data analysis were carried out by single factor experiment and Box-Benhnken (center group sum) orthogonal experiment method in the response surface analysis method. Optimized ratio of drilling mud for freezing holes in water-rich sand and pebble formations. Based on the engineering application of Beijing Metro Line 12, the optimized slurry ratio is adopted, that is, the content of bentonite is 7.18%, the content of hydrolyzed polyacrylamide is 0.20%, the content of sodium carboxymethyl cellulose is 0.19%, and the content of aluminum sulfate is 0.03%. %, the mud viscosity increased by 32%, the thickness of the mud skin increased by 20%, the filtration loss decreased by 30%, and the lubrication coefficient decreased by 60%. Significantly, the axial force on the drill pipe is reduced by an average of 15%, the torque received by the drill pipe is reduced by an average of 13%, the amount of bentonite in the mud and the loss of return flow are reduced by 30%, and there are no engineering accidents such as hole collapse, broken pipe and stuck drill, and frozen holes. The drilling efficiency and hole-forming quality are significantly improved.