When the pipeline is buried in quicksand layer or soft soil layer, the pipeline foundation is vulnerable to instability and fracture, causing interface disconnection and leakage, causing soil and water loss around the pipeline, pipeline sinking and damage, and road surface collapse. Therefore, to ensure the quality and long-term effect of pipeline repair, the pipeline foundation and surrounding soil must be grouted and reinforced before the repair of pipeline lining. At present, the drilling grouting construction technology is taken as a necessary measure in combination with other repair methods in the pipeline repair in quicksand areas.
1. Scope of Application
① The pipes are rainwater and sewage drainage pipes made of all materials.
② When the pipe diameter is greater than or equal to 800mm, the method of drilling and grouting inside and outside the pipe should be adopted; When the pipe diameter is less than 800mm, the grouting method of drilling down from the ground should be adopted. It can also be used for grouting treatment of crack and seepage of shaft wall and arch ring.
③ It is applicable to dislocation, disconnection, leakage and other pipeline structural defects, and the interface dislocation should be less than or equal to 30mm. The pipeline infrastructure is basically stable, the pipeline alignment has no obvious change, and the pipeline wall is solid and free from corruption.
④ It is applicable to preventive repair when the pipeline interface is in the leakage omen period or critical state.
⑤ It is not applicable to the repair treatment of structural damage such as pipeline foundation fracture, pipeline rupture, pipeline disconnection in inverted shape, serious dislocation of pipeline interface, and serious deformation of pipeline alignment.
⑥ It is not applicable to inspection wells with serious settlement and serious dislocation and damage of pipeline interfaces.
2. Basic methods
In combination with other drainage pipeline repair methods, the pipeline foundation soil mass shall be grouted and reinforced to fill the soil layer and voids with grout, so as to reduce the permeability of the soil layer, increase the soil strength and deformation modulus, fill the soil void, compensate the soil loss, and prevent leakage and rescue, and ensure the long-term normal use of the drainage pipeline.
② The consistency of cement mortar shall be determined according to the leakage of the pipeline and the gap size at the leakage point. Ordinary cement with strength no less than 42.5 shall be used. When the pores are large, appropriate fine sand or other inert materials can be added to the cement slurry.
③ Proportioning of commonly used drilling grouting materials. See the table for the ratio of grouting materials for soil reinforcement drilling around the pipe.
Proportioning of grouting materials for soil reinforcement
Grouting proportion shall be filled in the loose part of the roadbed cavity where the pipeline is sinking.