Prefabricated Technology for House Foundations

Prefabricated technology for house foundations is a key technique in construction engineering that ensures the quality and efficiency of foundation construction. Its core processes include construction preparation, site preparation, foundation treatment, excavation, and bedding layer laying. The following elaborates on these key steps:

1. Construction Preparation
Construction preparation is the foundation of prefabrication technology and requires coordinated efforts in personnel, materials, and equipment. First, organize construction personnel to familiarize themselves with design drawings, clarify the type of prefabricated foundation (such as independent foundation, strip foundation, or raft foundation), dimensions, elevation, and concrete strength grade requirements to ensure accurate construction parameters. Second, strictly inspect the appearance quality of prefabricated components, excluding defects such as surface cracks, honeycombs, and pits, and verify component models, specifications, and concrete strength reports to avoid rework due to component issues. In terms of materials, prepare reinforcing steel bars, concrete, formwork, supports, and embedded parts in advance to ensure their quality meets design standards; in terms of equipment, excavators, loaders, concrete mixers, and vibrators should be thoroughly debugged to avoid construction interruptions.

2. Site Preparation and Surveying Layout
Site preparation involves clearing obstacles and leveling the ground, while setting up drainage slopes, drainage ditches, and collection wells to prevent water accumulation from eroding the foundation. Surveying layout is crucial for positioning and requires the use of total stations and leveling instruments to lay out foundation axes, sidelines, and elevation control lines, and to set up permanent control piles and benchmarks to provide accurate references for subsequent construction. For example, axis deviations should be controlled within ±5mm, and elevation errors should not exceed ±3mm to ensure accurate foundation positioning.

3. Foundation Treatment
If the bearing capacity of the foundation soil is insufficient, reinforcement methods such as replacement bedding (such as gravel, sand, or lime soil), dynamic compaction, or compaction piles should be employed. Replacement bedding requires layered compaction, with each layer not exceeding 300mm in thickness, and the compaction coefficient should meet design requirements; dynamic compaction should adjust the compaction energy according to soil properties to ensure foundation density. After treatment, bearing capacity tests should be conducted, and only after passing can the next process proceed to avoid foundation cracking due to settlement.

4. Excavation and Trench Inspection
Excavation should strictly follow the axes and sidelines set by surveying layout. When excavating with an excavator close to the designed foundation bottom elevation, reserve 200-300mm of soil layer for manual cleaning to prevent over-excavation from damaging the foundation. After excavation, timely trench inspection is required to check whether the soil quality, elevation, and dimensions of the foundation bottom meet design requirements. If soft soil layers or groundwater seepage are found, immediate treatment and re-inspection are necessary to ensure the bearing capacity of the foundation bottom meets standards.

5. Bedding Layer Laying
The bedding layer is a transitional layer between the foundation and the foundation soil, with materials such as plain concrete, gravel, or lime soil, and its thickness is determined according to design requirements (usually 100-150mm). The bedding layer should be leveled and compacted, with a surface flatness deviation not exceeding ±10mm to provide uniform support and reduce the risk of uneven foundation settlement.