Practices for Grouting Pipelines in Prefabricated Houses

The practices for grouting pipelines in prefabricated houses should adopt targeted methods according to different scenarios. Common practices are as follows:

I. Grouting at Prefabricated Component Joints
Before construction, it is necessary to clarify the joint type, such as vertical sleeve grouting joints or horizontal splice joint grouting joints. Different joints have varying sleeve sizes, reserved hole positions, and grouting requirements. When grouting materials arrive on site, quality certification documents should be checked, and samples should be taken for on-site re-inspection of indicators such as fluidity, 3-day strength, 28-day strength, and setting time. It is strictly prohibited to mix grouting materials of different brands or models. At the same time, the sleeves and reserved holes自带 (自带此处推测为预制构件自带的，英文可处理为自带相关含义的表述，这里用“integral to the prefabricated components”体现) integral to the prefabricated components should be cleaned to ensure there are no blocked holes.

II. Grouting in Prefabricated Pipe Galleries

1. Material and Equipment Preparation: Use non-shrink self-leveling cement-based grouting materials, along with interface treatment agents, sealants, grouting pipes, and joint-sealing materials. Equipment includes high-speed mixers, grouting pumps, electronic scales, and fluidity testers.
2. Working Conditions: The installation of pipe gallery sections should pass acceptance inspection, with an axis deviation of ≤5mm and an elevation deviation of ≤3mm. The joint surfaces should be roughened to a depth of ≥5mm, exposing fresh aggregates, and then cleaned with a high-pressure water jet. The construction temperature should be controlled between 5-35℃. Construction is prohibited on rainy days or when rain is expected within 24 hours. The working area should be equipped with 1.2m-high guardrails and full safety nets, along with fire-fighting equipment.
3. Construction Process: Follow the sequence of base treatment → installation of grouting formwork → layout of grouting pipelines → interface treatment → preparation of grouting materials → pressure grouting → curing → formwork removal → quality inspection. When laying out the grouting pipelines, set a φ32mm grouting hole every 600mm along the perimeter of the pipe gallery, and install exhaust holes at the top of the joints and corners that are 300mm higher than the grouting surface.

III. Grouting for Subsidence of Backfill Soil in House Foundations
Select grouting materials such as cement slurry, expanding agents, or silicate slurry according to the soil properties of the foundation. When preparing, control the fluidity and curing time. The construction steps include: cleaning the foundation surface → embedding steel pipes or plastic grouting pipes → delivering the slurry through a grouting pump → controlling the grouting height according to design requirements → accepting the project after the slurry has cured.

IV. Pre-embedded Grouting Pipes in Construction Joints
Before pouring the concrete for the side walls, pre-embed disposable grouting pipes. The pipe body should have holes and be wrapped with geotextile, with an internal spring structure covered by rubber. Fix the grouting pipes with clips and nails at intervals of 200-300mm. For grouting pipes that are five to six meters long, install grouting conduits at both ends, and ensure overlap between pipes. After pouring, close the grooves with lids. When grouting, open the lids. Multiple grouting operations can be carried out repeatedly.