What is Pre Augering?
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What is Pre-augering?
Pre-augering is a ground preparation method used in sheet piling where an auger is drilled into the soil before installing the piles. The aim is not to excavate but to loosen dense or obstructive material that would otherwise increase resistance or cause pile deflection.
In practice, this allows the piles to be driven or pressed more cleanly, avoiding excessive stresses on the pile and equipment. It’s especially useful in urban environments, railway embankments, or sites where vibration and noise must be minimised.
At Steel Piling Solutions, we often combine pre-augering with low-vibration methods such as silent pressing or Movax systems—helping us maintain accuracy and programme certainty, even in challenging ground conditions.
Why Pre-augering is Used in Sheet Piling
Sheet piles are typically installed using vibro hammers, impact driving, or silent pressing. But these methods can quickly meet their match when ground conditions include:
Stiff or over consolidated clays
Dense sands, gravels, or cobbles
Historic fill, buried obstructions, or reinforced concrete
Zones with unpredictable layers and high refusal risk
Without pre-augering, these materials can prevent piles from reaching the designed depth. Worse, they can cause damage, misalignment, or lead to programme delays.
Pre-augering solves this by preparing the ground before installation. The process softens the resistance just enough to guide the pile down to depth, keeping alignment true and reducing the force required. This is essential when working near:
Rail assets
Underground services
Live buildings or retaining structures
Sensitive heritage sites
It’s also an effective support strategy for silent piling methods where brute force is not an option. By removing the toughest layers ahead of time, we make precision installation achievable—even where vibration-free requirements are in place.
How Pre-augering Works in Practice
Pre-augering is typically carried out using a piling rig or excavator fitted with an auger attachment. The auger drills boreholes to a pre-determined depth—usually just short of the final pile toe level—and follows the exact line where the sheet piles are to be installed.
There are a few approaches depending on the ground and installation method:
Continuous augering: This is carried out along the full length of the wall before any sheet piles are installed. It’s common on linear walls in uniform ground conditions or when piles must follow a strict alignment.
Targeted augering: Used when only certain sections of the line contain hard spots, buried obstructions, or high-resistance layers. This is often guided by previous ground investigations or refusal data from earlier installations.
Support augering for silent piling: When using systems like Movax or Giken, augering is often carried out at regular intervals to help overcome resistance while maintaining low vibration and noise levels.
Typically, the borehole diameter is kept slightly smaller than the sheet pile width. This ensures the pile still beds into the surrounding ground tightly, maintaining integrity and load transfer while reducing resistance.
Ground Conditions That Require Pre-augering
Pre-augering becomes essential when ground resistance poses a risk to productivity, precision, or safety. We typically recommend it on sites where:
Urban and brownfield environments
Often contain buried rubble, brickwork, and legacy foundations. Augering helps clear these obstructions while reducing the risk of pile damage or misalignment.
Railway embankments and infrastructure
Pre-augering allows us to install piles with minimal ground movement and vibration, protecting adjacent track beds, signalling, and drainage.
Mixed or granular fill
Sites made up of backfill, boulders, or coarse gravels are unpredictable and often show variable refusal depths. Augering levels the playing field and improves installation control.
Low-impact or vibration-free piling zones
Where noise, vibration, or ground disturbance must be kept to a minimum—such as near hospitals, heritage buildings, or live utilities—pre-augering supports silent piling techniques.
Restricted access or tight-tolerance environments
On sites with little room for rework or margin for error, augering helps avoid delays caused by refusal and keeps the installation programme moving forward.
Machinery and Techniques Involved
Pre-augering can be completed using a variety of equipment depending on the access and ground conditions. This includes:
Excavators fitted with auger drives
Piling rigs with interchangeable auger heads
Specialist rotary or CFA rigs for deeper or larger diameter bores
On many SPS projects, we use our own Movax-equipped rigs, allowing us to switch between pre-augering and vibro or silent pile installation efficiently. The auger type and depth are chosen based on site investigation data and the final pile design.
Benefits of Pre-augering for Sheet Pile Installations
Reduces resistance and ensures piles reach designed toe levels Minimises vibration — essential near sensitive assets or infrastructure Improves alignment by guiding the pile along a prepared vertical path Supports low-impact methods like Giken or Movax in difficult ground Prevents refusal, delays, and pile damage in known hard strata
By dealing with problem ground up front, pre-augering reduces the risk of issues mid-installation and helps us keep piling operations efficient and on schedule.
Common Misconceptions
“It weakens the ground too much.”
Incorrect. Boreholes are kept narrow and controlled—enough to reduce resistance, not structural integrity.
“You don’t need it with vibro rigs.”
Even high-frequency vibrators can struggle in dense or mixed strata. Pre-augering often prevents refusal and deflection.
“It slows down the programme.”
In reality, it often speeds things up by avoiding time-consuming refusals or misalignment corrections.
Is Pre-augering Right for Your Project?
Pre-augering isn’t always required—but on the right site, it can make a major difference. If your project involves hard ground, buried obstructions, or low-vibration installation methods, pre-augering can be the key to smoother progress, better pile alignment, and fewer delays.
At Steel Piling Solutions, we assess every project on its merits. When pre-augering is needed, we provide the right rigs, experienced operators, and seamless integration with silent or vibro piling systems to get the job done efficiently and safely.