Construction Technology of Roadway Pre-grouting Reinforcement in Long-distance Sand Seam

According to the characteristics of low cohesion,bad cementation and easy caving for the whole section sand seam in main belt drift of Xiayukou coal mine,a new construction technology and technical points of small duct grouting were introduced.Pre-grouting water glass and calcium chloride could improve the compressive strength of sand effectively,make the surrounding rock have self-stability and ensure safety and normal excavation of the roadway.