Hi Jeremy,
Thank you for raising this question. This is a topic that comes up frequently in practice, yet is not always well addressed in formal design guidance.
From an engineering standpoint, I agree with your observation: there is limited definitive documentation that explicitly quantifies how pre-augering alters the analytical assumptions of sheet pile or soldier beam systems. Most available references discuss when pre-augering is beneficial rather than how to rigorously modify design parameters to account for soil disturbance.
Based on both practical experience and geotechnical principles, several considerations should be highlighted:
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Site-Specific Soil Characterization
Any evaluation should begin with a thorough subsurface investigation. Soil type, density/consistency, and groundwater conditions are critical. In particular, the presence of a high groundwater table (or offshore conditions) introduces additional complexities, including pore pressure redistribution during installation.
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Effect of Pre-augering on Soil Behavior
Pre-augering inherently disturbs and partially loosens the soil, reducing lateral confinement and temporarily decreasing shear strength along the installation path. However, in many cohesive or partially saturated soils, some reconsolidation or "set-up" occurs after installation, which can partially restore resistance.
In granular soils or mixed ground (e.g., gravels, cobbles, or fill with obstructions), the method is often beneficial simply to facilitate installation without causing excessive refusal or damage to the section.
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Observed Structural Effects
As you noted, the general consensus from field experience is that pre-augering may lead to:
- Slightly increased deflections
- Potentially reduced initial lateral resistance
However, these effects are typically not severe enough to compromise overall system performance when the system is conservatively designed.
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Field Experience and Instrumentation
In my experience working with driven piles and offshore installations, instrumentation such as CPT (Cone Penetration Testing), including seismic CPT or downhole geophysics, has been extremely valuable in understanding in-situ soil response. These methods provide insight into soil stratigraphy, stiffness, and wave propagation characteristics, which can be used to refine embedment depth and structural demand particularly in seismic or critical applications.
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Construction Considerations and Mitigation
Pre-augering is particularly effective in:
- Dense clays
- Gravelly soils or cobbles
- Obstruction-rich fill
Where concerns exist regarding loosened soil around the section, one practical mitigation approach is to follow installation with pressure grouting (cement or cement-sand mixtures). This can help densify the surrounding soil mass, improve contact, and reduce potential loss of lateral support.
Professional Perspective
While anecdotal evidence and field experience strongly support the effectiveness of pre-augering, it is true that providing "proof" in a strict analytical sense is challenging. In practice, justification is often based on:
- Demonstrated constructability benefits
- Empirical performance from similar projects
- Conservative design assumptions (e.g., reduced lateral soil parameters if warranted)
Ultimately, I would recommend framing the response to the agency around a combination of:
- Site-specific geotechnical data
- Engineering judgment supported by precedent
- Conservative design adjustments, if necessary
Relevant References (for general guidance)
You may find the following resources useful for supporting documentation:
- https://projects.arcelormittal.com/media/iaqnpcdv/installation-of-steel-sheet-piles-2024-en-web.pdf
- https://www.sheetpilinguk.com/sheet-piling-methods/ancillary-techniques/
- https://www.steelpilinggroup.org/guidance/construction/pile-driving-installation-methods/
I hope this perspective is helpful. While each project ultimately depends on site-specific conditions, your observations are consistent with what has been seen across many installations. If needed, I would be glad to discuss this further in more detail.
Best regards,
Rolando Ayala
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Rolando Ayala
Project Management
River Edge NJ
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Original Message:
Sent: 05-21-2026 06:04 PM
From: Jeremy Shively
Subject: Pre-auger for Sheet Pile / Solider Beam Installation
I am curious if anyone has any engineering documentation on the use of pre-augering (loosening the soil with an auger without removing soil from the hole) in difficult soils to make the driving (usually with a vibratory hammer) of sheet piles and/or soldier beams easier. I have found references that indicate when it might be beneficial, but have not found design guidance on whether the analysis of the system is altered by disturbing the soil. I have had this method used on projects in the past, and have discussed the topic with other design engineers and pile driving contractors. The general consensus I have come across is that the method works and does not greatly affect the design of the system (most mention that perhaps the sheet/beam might deflect more that otherwise anticipated), but I have not found any resources that formally address the topic from an engineering standpoint. Anecdotally, I know it works from experience, but I have recently been asked by an agency for some sort of "proof" or to provide a calculation to show that it works and does not negatively impact the system as a whole. I would be interested to hear any information/opinions from others whether it be anecdotal or formal documentation on the subject. Thanks!
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Jeremy Shively, P.E.
Engineer V
Granite Construction Company
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