Prefabricated Square Piles for Four-Electric Buildings

When using prefabricated square piles for four-electric buildings (communication, signaling, power, and electrification buildings), it is necessary to comprehensively consider pile characteristics, applicable scenarios, specification selection, and construction key points.

I. Core Characteristics of Prefabricated Square Piles

Prefabricated square piles are factory-standardized square concrete piles with square or rectangular cross-sections, commonly with side lengths ranging from 30 to 50 centimeters. They undergo strength development through processes such as steam curing in the factory and can be used directly upon arrival at the construction site. Their core advantages include:

• Quality Control: Factory production avoids weather interference during on-site pouring, ensuring uniform concrete strength.
• Efficient Construction: On-site curing time is eliminated, allowing the piles to bear loads immediately after driving, thus shortening the construction period.
• Cost-Effectiveness: The cost is approximately 30% lower than that of bored piles, making them suitable for projects with limited budgets.
• Strong Adaptability: Particularly suitable for soft soil foundations and buildings up to seven stories high, with excellent anti-settlement performance.

II. Applicable Scenarios for Four-Electric Buildings

Four-electric buildings have high requirements for foundation stability, and prefabricated square piles are suitable for the following scenarios:

• Soft Soil Foundation Reinforcement: By transferring loads to deeper soil layers through the piles, uneven settlement is reduced.
• Existing Building Reinforcement: Reinforced concrete solid prefabricated square piles (resistant to acids and alkalis) can be customized in specifications (e.g., from 100100mm to 250250mm) to match the original foundation.
• New Construction Foundations: As pile foundations under independent foundations or raft foundations, they enhance overall load-bearing capacity.

III. Specification Selection and Customization

According to the building load and geological conditions, the specifications of prefabricated square piles need to be selected differentially:

• Light Buildings (e.g., single-story signaling buildings): 100100mm or 150150mm piles can be selected to meet foundation load-bearing requirements.
• Medium Buildings (e.g., 3-5 story power buildings): 200*200mm piles are recommended to balance cost-effectiveness and load-bearing capacity.
• Heavy Buildings or Soft Soil Areas: 250*250mm large-specification piles are used, or stability is enhanced by densifying pile arrangement.
  All specifications support customization of length and reinforcement to adapt to complex geological conditions.

IV. Key Construction Points

Construction must strictly follow operational specifications to ensure the performance of the piles:

• Pile Lifting and Alignment: When the pile tip is 50 centimeters from the hole opening, the axis is rechecked, with a verticality deviation of ≤0.5%.
• Pile Stabilization and Sinking: During the initial driving stage, the drop distance is ≤0.8 meters. After entering the soil by 1 meter, full-stroke hammering is used, with a maximum drop distance of ≤1 meter.
• Pile Joining Process: Carbon dioxide protection welding is preferred for symmetrical welding. After welding, natural cooling is required for ≥8 minutes, and water cooling is strictly prohibited.
• Pile Sending Control: A 10-millimeter elastic cushion layer is set between the pile sender and the pile top, with a pile sending depth of ≤2 meters.
• Hammer Stopping Criteria: Both the designed elevation and the penetration of the last three blows (≤20 millimeters/10 blows) are controlled. In case of abnormalities, hammering is stopped immediately for inspection.

Through scientific selection and standardized construction, prefabricated square piles can significantly enhance the foundation stability of four-electric buildings, ensuring long-term safe operation.