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Submit your enquiry using our online form and include a brief message about the type of issues you are experiencing. One of the Mainmark experts will contact you as soon as possible.

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Soil Replacement


Improving ground conditions

New Zealand has a complex geology including soft, compressible and liquefaction-prone soils.

Dense urban areas also tend to be located on alluvial plains and in coastal regions. Buildings in these areas are sitting on sandy, shifting soils. 

Over 50% of New Zealand’s population faces moderate and higher liquefaction susceptibility. Out of this group, 25% are facing high or very high liquefaction susceptibility. As a result, New Zealand has experienced a growing demand for ground improvement. This has seen an increase in the construction and retrofit of buildings and infrastructure, which need suitable foundations to ensure their long-term durability and safety. 

Whether seismic activity impacts a specific site or structure, and to what extent, depends on the ground conditions and structural system present. 

In coastal and alluvial regions, soil replacement methods are effective in improving ground conditions. This involves the excavation and removal of unsuitable soil, and replacement with engineered fill material.

Mainmark Solutions

Terefil is a Mainmark technology to create a lightweight cellular concrete.

Cellular concrete has found extensive use in construction and civil engineering applications due to being lightweight while still retaining good compressive strength. Terefil is effective for improving ground conditions in areas with soft, compressible soils. 

Technical Category 3 (TC3) means that moderate to significant land damage from liquefaction is possible in future significant earthquakes. 

By upgrading the soil quality of your TC3 land, you open up new building options that improve safety and reduce costs. These options are often less expensive than TC3 foundations.

Geotechnical investigation and engineering design is required for TC3 land, to help identify the best way to reduce risk of injury to people and damage to your property in future earthquakes. 


Terefil Raft for Soft Soils


Terefil Raft for Liquefiable Sites

Features & Benefits

The lightweight yet strong nature of cellular concrete makes it an ideal soil replacement solution. Numerical modelling has also shown that Terefil raft performs twice as well as reinforced gravel raft, while only needing half as much excavation.

Cost Effective

Save on excavation time and disposal costs compared to traditional methods

Minimal Disruption

No vibration and can be set up 30 -60m away from excavation

Save Time

Entire raft poured in one day. “Save construction time and overall build timeline”

Decreases differential settlement

Decreases differential settlement and can be designed to mitigate primary consolidation settlement

Need help?

Need Help With A Project? Contact Us Today

Get a quote

Arrange a site assessment in 3 simple steps:

Step 1

Submit your enquiry using our online form. Include a brief message about the type of foundation issues you are experiencing.

Step 2

Our friendly customer service team will be in touch to schedule a site assessment that suits you.

Step 3

One of the Mainmark experts will visit your commercial property, assess the damage, and ascertain the likely cause. They will establish the approach needed, creating a plan specific to the needs of your building and provide you with a detailed quote.

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Resources & downloads

The Use Of Terefil Rafts To Control Static Settlement Under Building Loads

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