6 common issues that can occur when driving piles and how PDM can help solve them

Pile Driving Monitoring (PDM) is often overlooked on projects until something goes wrong, but why not make it part of the schedule from the beginning? In this article you’ll discover 6 common issues that can occur when driving piles on site and how PDM can help solve them.

1. The tip of the pile could buckle

Pile tip damage No project wants to incur delays or additional costs, so for an installation contractor, premature pile refusal is one of the most unacceptable risks that can happen on site. It happens when the pile doesn’t reach its target penetration depth and so the anticipated design can longer apply. This occurs with steel piles, in both onshore and offshore projects due to their diameter and wall thickness, which can make them more susceptible to pile tip buckling as they’re driven into hard soils or soils with an unexpected structure (like rock layers or boulders).

Often, these problems are addressed retrospectively and the G-Octopus team have experience assessing in-situ pile capacity in case of premature pile refusal. But instead of trying to fix an issue once it’s already occurred, why not include it early?

Carrying out numerical analysis to simulate the buckling conditions can lower the construction risk considerably.

2. There may be damage along the pile

Whether you’re driving a concrete or a steel pile, damage can occur along the pile shaft including cracks and other anomalies. If the integrity of the pile is damaged, it’s likely to cause problems with the remaining structure installation.

Pile driving monitoring and specifically using fibre optic sensors, is a reliable method of monitoring the integrity of an entire pile. When compared to standard pile driving monitoring which only provides an estimate of the distribution of resistance along the shaft, fibre optic sensors allow stresses to be measured during driving over the entire length of the pile, providing more accurate results from top to bottom to help inform the installation process.

3. The soil profile is different to what was expected

What starts out as a simple project can become more complicated and construction can even be suspended if there are concerns with the attainable pile capacity because the soil profile is different to what was expected.

Pile monitoring and acceptance procedures can help to overcome issues like unusual soil profiles and long-term creep behaviour without the need to bring in longer, or shorter piles, saving a project both time and cost.

4. It’s taking more or less strikes than expected to drive the pile to the right depth

Before installation occurs, an analysis of the soil should have been carried out to accurately predict how many times the hammer would need to strike the pile in order to install it to the correct depth. If the number of strikes required differs significantly, it’s likely there’s a problem, but without the relevant data to help you, it could be difficult to understand where this problem comes from.

In this situation, pile driving monitoring can help to assess the pile behaviour. It can provide key elements for calculating the soil resistance at the time of monitoring as well as information and on driving system performance.

5. The piles are an uncommon shape

Usually steel piles are long cylindrical structures, but what happens when their design or their base is a different section? One example of this is H steel piles.

If the piles don’t drive as expected, it can cause unwanted problems and delays for the contractor.

Drawing on the experience of a team dedicated to deep foundation testing and monitoring means they know the best methods to use to avoid project delays such as undertaking numerical analyses to accurately simulate the test.

6. The piles need to be approved on site

Finally, although this issue is a little more unusual, and dependent on location, sometimes piles need to be approved on site and fit certain criteria as required by standards, such as the Eurocode.

By engaging specialists in PDM, their experience means they have the expertise to devise and set up pile testing procedures specific to the site. They’ll make sure all possible installation cases are allowed for, have staff available 24/7 to confirm the final pile installation and all without causing delays to the project.

Even projects that look simple in theory can come across problems during construction. By involving pile driving monitoring from the beginning, you’ll have the information you need to progress according to plan, reduced risk and if the unexpected does occur, a team of experts to draw on their expertise to find a solution, quickly.

Source: Figure 1 – Widening a harbor basin, demolition of a deep see quay wall in Rotterdam, the challenge of ever growing ships at the ETC Delta; Erik Broos, Rob Sibbes, Jarit de Gijt, (2017).