The erosion challenge beneath ports and seawalls

Even the most durable marine infrastructure deteriorates over time. Ireland's constant exposure to harsh environmental conditions, particularly along its Atlantic coast, accelerates this process, with water movement being one of the most damaging forces.

Wave and tidal action continually wash out backfill material through cracks, joints, or weep holes, removing sand and finer particles from behind or beneath seawalls and port structures. Over time, this undermining creates voids that enlarge and eventually compromise structural support. In vertical seawalls, especially those with shallow foundations, reflected wave energy can scour the toe of the structure, further accelerating erosion.

Hydrostatic pressure also plays a key role. Heavy rainfall, particularly along the Atlantic coast, can lead to groundwater accumulation behind seawalls, which can force water through small openings. As this water escapes, it carries soil particles with it, gradually weakening the backfill.

Alongside natural processes, port infrastructure must also withstand significant operational loads. Cranes, container stacks, and heavy vehicles exert intense pressure on quay slabs and underlying soils. In areas underlain by compressible material, around the Port of Dublin for example, this loading can accelerate settlement and void formation posing a potential risk to operations and asset integrity.

Climate change and increased exposure

The frequency and intensity of extreme weather events are projected to rise as the climate changes, further increasing the rate of erosion. The Environment Protection Agency says that sea level around Ireland has risen by 2-3mm per year since the 1990s and are projected to rise by up to 1.0 metre by the year 2100. The Agency says, "storm surges and extreme waves pose an ever-increasing threat to Ireland as sea levels continue to rise, including for many coastal cities such as Cork, Dublin, Galway and Limerick, and to critical infrastructure". It warns that soft sediment shorelines "are particularly at risk".

Key considerations for engineers and contractors

Erosion beneath coastal and port infrastructure is clearly a serious and growing risk. Mainmark's advice to asset owners and operators to manage this risk is to:

• Conduct subsidence and ground-condition investigations early, particularly around seawall toes and quay foundations.

• Design remediation provision with tidal cycles, groundwater movement, and long-term climate impacts in mind.

• Select remediation solutions that enable rapid intervention, minimal excavation, and continuous port operations.

With the right modern ground-stabilisation strategy asset owners can protect structures, minimise downtime, and avoid costly large-scale repairs.

Limitations of traditional remediation methods

Conventional ground remediation solutions such as piling or underpinning, while effective, can be slow, expensive, and disruptive in Irish coastal settings. Similarly, in busy port environments, the required excavation, machinery access, and shutdown time represent significant operational and financial challenges. As a result, traditional repairs often become impractical or unaffordable for asset owners needing rapid, reliable intervention.

A modern, low-disruption solution

A faster, less disruptive approach is Mainmark’s engineered injection solution. With this technology, solution resin is injected directly into the ground through small tubes, typically no more than 25 mm in diameter, allowing work to proceed without major excavation or interruption to port operations – keeping downtime and resulting costs to a minimum.

Key benefits include:

• Void filling: as the solution expands, it fills washouts and voids beneath and behind slabs, reinstating the ground’s load-bearing capacity.

• Soil densification: Teretek® compacts weak or loose soils, improving ground strength and stability around seawalls, quay structures, and hardstandings.

• Crack and joint sealing: by penetrating and sealing fractures and gaps, the resin helps prevent future erosion and water ingress.

• Re-levelling of critical assets: Teretek® can gently lift and re-level slabs, pavements, and operational surfaces to ensure safe, reliable support for heavy port equipment.

In addition, the process also requires no heavy machinery, provides immediate results, and has zero environmental impact making it particularly well suited to sensitive marine locations.

Mainmark’s experience

As a ground engineering specialist, Mainmark has delivered ground improvement, void filling, and level correction solutions to port terminals and coastal structures worldwide for more than 30 years. The team understands the importance of minimising operational disruption and works efficiently within tight shutdown windows, including in emergency repair situations.

To discuss tailored ground-stabilisation solutions for Irish marine and coastal infrastructure, contact Mainmark Ireland.