大直径顶管穿越沙漠深部护壁浆液体系研究与应用

Research on the Wall Protection Slurry System of Large Diameter Pipe Jacking Across Deep Desert and its Application

大直径顶管穿越沙漠深部顶进阻力大、地层稳定性差、易垮塌、冒顶、护壁困难,砂层多夹有最大直径达4 cm的圆砾,管道最大埋深达50 m,国内外尚无顶管护壁浆液能有效稳定深部砂层降低顶进阻力。本文提出粘土-CMC聚合物浆液用作沙漠深部大直径顶管护壁,探讨浆液护壁及渗透机理,研究浆液性能随材料加量变化的关系,重点分析流变性、失水造壁性、润滑性的变化规律,得出浆液最优化配比。工程应用表明,该护壁浆液能有效稳定砂层,保护隧洞,降低顶进阻力,大直径顶管成功穿越沙漠深部,最大轴线偏差未超过50 mm,顶力未出现急速增长。

The large-diameter pipe jacking through deep desert layers always encounters several problems such as big resistance,poor stability of strata,prone to collapse,roof collapse,and difficult wall protection.The sand layers tend to include big round gravel up to 4 cm in diameter and the maximum depth of the pipeline is up to 50 m.There is no pipe-jacking retaining wall slurry at home and abroad that can effectively stabilize the deep sand layer and reduce the jacking resistance.In this paper,a clay-CMC polymer slurry is proposed as a large-diameter top-tube retaining wall in deep layers of the desert,and the mechanism of slurry wall protection and infiltration is explored.Then the relationship between slurry performance and the amount of material added is studied.The emphasis is placed on the analysis of the rheology,fluid losing and wall-forming,and lubricity changes,resulting in an optimal slurry ratio.The engineering application shows that this retaining wall slurry can effectively stabilize the sand layer,protect the tunnel and reduce the jacking resistance.Consequently,the large-diameter pipe jacking can pass through the desert deep strata successfully with the maximum axis deviation not exceeding 50 mm and the jacking force does not grow rapidly.