When constructing basements, the sequence of pile driving can significantly impact the surrounding soil and structures. Driving piles from the center outwards tends to displace soil laterally, potentially causing damage to nearby buildings, utilities, or infrastructure. This outward movement can lead to soil heave, settlement, or even structural instability in adjacent areas.
Conversely, driving piles from the outer perimeter inwards minimizes lateral soil movement. This method compresses the soil towards the center, creating a denser and more stable foundation. Additionally, it generates excess pore water pressure, which temporarily increases the soil’s resistance to the pile driving force. This can result in piles being driven to shallower depths than initially planned.
However, this excess pore water pressure dissipates over time, and the soil’s bearing capacity decreases. Consequently, the shorter driven piles may no longer be able to support the original design loads, posing a risk to the structural integrity of the basement. To address this issue, redriving is necessary. After the excess pore water pressure has dissipated, the piles are driven deeper to ensure they reach the required bearing capacity and provide adequate support for the basement structure.
In conclusion, the sequence of pile driving in basement construction has significant implications for soil behavior and foundation stability. While driving piles from the outside inwards minimizes lateral movement and creates a denser center, it can lead to initially shorter pile lengths due to temporary excess pore water pressure. Redriving after pressure dissipation is crucial to ensure the piles meet the design load requirements and provide a safe and stable foundation for the basement.