In Which Cases Is Pre-Drilling Required Before Pile Pressing?

Based on many years of experience in concrete pile pressing and foundation construction, we have found that pre-drilling is required in the following situations:

- When encountering hard soil or rock layers with high SPT values. Specifically, clay with SPT N30 > 8 or sand with SPT N30 > 15, where the pressure applied beneath the pile toe is insufficient to penetrate the layer. In such cases, pre-drilling is necessary to enable the pile to reach the designed tip elevation.

- When the soil profile is non-uniform and contains hard lenses with high SPT values. Pre-drilling through these hard layers helps ensure that the pile reaches the required design depth and tip elevation.

- To allow the pile toe to bear on a stable soil or rock layer. This improves pile stability and prevents sliding when constructing foundations in hilly or mountainous areas.

- To prevent false refusal during pile pressing when working in sandy soil conditions.

- To minimize soil heave and reduce the risk of affecting adjacent structures, especially when construction is carried out in densely populated urban areas.