沙漠地区大直径顶管施工护壁减阻浆液研究与应用

Research and Application of Wall-reducing Slurry for Large Diameter Pipe Jacking in Desert Area

沙漠地区地层稳定性差,摩阻力大,导致长距离大直径顶管施工时间长,浆液输送压力损失大,极易造成地层垮塌埋管,顶管阻力急剧增加导致顶进失败。沙漠地区大直径顶管工程顺利顶进的关键是浆液应具有较好的润滑减阻和成套护壁作用。基于这一关键问题,开展室内试验和现场应用研究,研发出了适合沙漠地区顶管的新型护壁减阻浆液,采用高岭土聚合物浆液作为机头同步注浆浆液,无粘土高聚物浆液作为沿线跟进补浆浆液。同步注浆浆液在润滑减阻的基础上主要突出成套护壁作用,而跟进补浆浆液主要突出润滑减阻特性,从而使润滑减阻浆液系统达到最佳的润滑和护壁作用。研发的新型护壁减阻浆液应用于内蒙古乌兰布和沙漠穿沙输水项目7~9号顶段——国内外首例沙漠地区大直径顶管工程,效果良好,顶进工作顺利完成。该研究提升了沙漠地区顶管工程关键技术、解决了护壁与减阻问题,具有极大的社会价值和经济效益。

In the desert area, the stratum stability is poor and the frictional resistance is large, resulting in long distance and large diameter pipe jacking construction for a long time. The pressure loss of slurry transportation is large. It is easy to cause formation collapse and burying. The key to the smooth jacking of the large diameter pipe jacking project in the desert area is that the slurry should have good lubrication resistance and complete wall protection. Based on this key issue, indoor trials and field application studies were carried out to develop a new type of wall-reducing slurry suitable for pipe jacking in desert areas. Kaolin polymer slurry was used as the synchronous grouting slurry for the nose and the clay-free polymer slurry was used as a follow-up slurry along the line. On the basis of lubrication resistance reduction, the synchronous grouting slurry mainly focuses on the complete wall protection function, while the follow-up grouting slurry mainly highlights the characteristics of lubrication and drag reduction, so that the lubrication and drag reducing slurry system can achieve the best lubrication and wall protection functions. The new type of wall-reducing slurry for resistance reduction was developed for the first large-diameter pipe jacking project in the desert area at the top of 7～9 in the Ulan Buh desert sand-carrying water project in Inner Mongolia. The effect was good and the jacking-in work was successfully completed. The study has improved the key technologies of the pipe jacking engineering in desert areas, solved the problem of wall protection and drag reduction, and has great social and economic benefits.