Foundation of Prefabricated Concrete Houses

There are various methods for constructing the foundation of prefabricated concrete houses, and the appropriate approach should be selected based on geological conditions, house type, and design requirements. Common methods and key points are as follows:

1. Compaction Method for Foundation Reinforcement

Repeatedly compact the original foundation soil layer using a pneumatic hammer or heavy-duty road roller to increase soil density to the bearing capacity standard (usually above 150 kPa). This method is suitable for areas with relatively uniform soil quality and moderate moisture content, effectively reducing the risk of foundation settlement. During operation, compaction should be carried out in layers, with each layer controlled at a thickness of 20-30 cm, and the degree of compaction should be tested to ensure compliance.

2. Soil Replacement Method

Excavate loose, weak, or overly moist soil (such as silt or humus) from the foundation and replace it with denser and more stable materials (such as gravel, sand, or lime-soil), which are then backfilled and compacted in layers. Although this method incurs higher costs, it significantly improves foundation performance, especially in areas with poor geological conditions or sensitivity to settlement. Attention should be paid to the gradation and compaction quality of the backfill material to avoid uneven settlement in the later stages.

3. Piling Method

Embed reinforced concrete piles (such as prefabricated concrete piles or steel pipe piles) into soft soil layers to transfer loads to deeper stable soil layers or rock formations, enhancing foundation bearing capacity. This method is suitable for small buildings or areas with complex geological conditions (such as soft soil or collapsible loess), but its bearing capacity is limited. The length, diameter, and spacing of the piles should be determined based on the building weight and geological report.

4. Reinforced Concrete Independent Foundation

Design Requirements: The characteristic value of foundation bearing capacity should be no less than 150 kPa, and the top surface elevation should be ±0.000 m (0.3 m below the outdoor ground level) to prevent rainwater backflow. Construction Process:

1. Level the site, set out and position, and excavate to the designed foundation pit depth;
2. Pour a 100 mm thick concrete cushion;
3. Bind reinforcement and install embedded steel plates (for connecting the house steel beams);
4. Erect formwork and pour concrete (using P·O 42.5 cement, medium-coarse sand, and 5-25 mm gravel, with a strength grade of no less than C25);
5. Cure until the designed strength is reached and then remove the formwork. This foundation type offers high stability and is suitable for low-rise buildings such as rural self-built houses and villas, but strict control over material quality and construction techniques is required.

5. Key Points for Construction Preparation

1. Technical Preparation: Familiarize yourself with construction drawings and geological reports, prepare technical disclosure documents, and transfer and mark the foundation axis using a control network;
2. Material Preparation: Purchase qualified cement, sand, gravel, and reinforcement, and customize embedded steel plates (requiring anti-corrosion treatment);
3. Equipment Preparation: Equip with excavators, concrete mixers, vibrating rods, total stations, and other equipment to ensure construction efficiency.

Selection Recommendations: When geological conditions are favorable, prioritize the compaction method or soil replacement method; for soft soil foundations, piling or reinforced concrete independent foundations are recommended; for commercial buildings or high-rise buildings, a composite foundation should be designed based on professional geological survey results.