Abstract: Based on the underground excavation engineering of Liaogongzhuang station on the west extension project of Beijing metro line 6, center about the uneven characteristics of the poorly-graded sand, the instable structure, the crushed gravel layer and the pebble stacking, and the own risk of the shallow tunnel. By comparison, determine to adopt the double tube WSS retreating deep hole grouting technology to pebble stratum, introduce thematerials of deep hole grouting technology, the machines, the grouting pressureand the detail process etc. Aiming at providing some experience and reference to the similar projects.