Pile driving is a complex process that involves a lot of manual labour and skill to achieve a high-standard installation. But did you know that there’s also a lot of science involved in how pile driving works?
From geotechnical engineering and mechanical engineering to physics and mathematics, let’s take a closer look at how piling techniques use science as a backbone.
Quick summary: What is pile driving?
Pile driving is the act of installing long columns (called piles) into the ground, and they’re usually made from steel or concrete. These columns can act as structural foundations for buildings, as they transfer the weight of the load to stable soil beneath the surface.
The mechanics of pile driving
Physics plays a huge role in a piling installation, with friction and load-bearing giving each pile its essential stability and security.
Piles are driven into the ground using repeated force, and this driving motion is either delivered by impact, vibration, or a combination of both using pile drivers. This drives the pile deeper into the ground while simultaneously increasing the pile’s resistance, until it reaches its target depth or load capacity.
How does a pile form resistance?
There are two main forms of resistance involved in a pile installation:
- End bearing: The pile is driven into the ground until it reaches a firm, stable layer. The pile can then distribute the load along its whole length to the load-bearing layer using resistance.
- Skin friction: If the pile cannot reach a load-bearing layer, friction can be used to build resistance between the pile surface and the soil surrounding it.
Geotechnical engineering and soil conditions
Piling relies a lot on a site’s soil conditions, making geotechnical engineering — specifically soil mechanics — a core science that underpins all piling installations.
This is because there are many different types of soil with varying properties, which can also impact how the pile is driven and how effective it is for load bearing.
Cohesive soils (clays)
- Depend mainly on skin friction piles
- Can increase pile resistance over time as pore water pressure dissipates
Granular soils (sands and gravels)
- Work better with end-bearing piles
- Can cause densification — improves pile stability, but can make driving more complex
Rock and dense soils
- Require a lot of driving force
- More compatible with shorter piles, as they can support a greater amount of weight
Soil mechanics and rock mechanics support the piling process by allowing specialists to:
- Understand the qualities of different soil types, from density and friction to strength
- Determine bearing capacity (what the pile can hold) and settlement behaviour (how the soil will react and move when force is applied)
- Analyse how the soil and pile interact with one another, like with end-bearing resistance and skin friction resistance
- Predict how soils change when faced with load-bearing, moisture changes, and vibrations
All of these considerations make piling a secure and reliable foundation technique when carried out correctly.
Mathematics and load-bearing capacity
One of — if not the most — important consideration of a piling installation is ensuring that the piles can hold the maximum weight of a structure without failing. After all, that is their entire purpose!
One empirical formula is used to underpin an entire piling project, and if the figures are inaccurate, this can result in pile misalignment, wastage, and even structural failure.
The two most important aspects in this formula are a pile’s tip resistance (end-bearing capacity) and shaft resistance (skin-friction capacity). Together, they equal a pile’s total load-bearing capacity.
Learn more: Understanding load-bearing capacity in piling foundations
Why is understanding the science behind piling important?
It’s easy to think that piling is just a construction task that relies on sheer force, but there’s actually a lot more science at play behind the scenes.
Without knowing how science can impact pile driving, there’s a greater risk of structural instabilities, costly errors, project delays, and even complete failure. Science is what makes piling a trusted and safe construction method that so many rely on in the build of bridges, high rises, residential buildings, and more.
WL Piling: Your local North West piling contractors
We’ve been offering our clients piling services in the North West for over 50 years.
Our skilled piling specialists are experienced in installing foundation, grundomat, driven, mini piles and more to suit any project — no matter the scope or size. We focus on excellent customer service and health and safety compliance as a priority.
Get a free quote today by contacting our friendly team. Call 07525 497 677, email chris@wlpiling.co.uk, or fill in our contact form.
