What do holes and voids mean?
‘Voids’ can mean anything from cracks and crevices, up to the huge volume voids caused by a major tunnel collapse.
Holes and voids can be either concealed or open cavities that present naturally as a result of erosion and geological changes, or due to building, mining, and other commercial or industrial ground activity. Ranging from small to large, all holes and voids underneath structures will contain air, and possibly water, which can cause instability. Filling these spaces can prevent wider damage to the ground, on-ground structures, and the surrounding environment.
Some holes and voids may need to be backfilled after operations cease, to prevent them becoming a hazard.
Safety upgrade of a hazardous weir with Terefil®
Fill the void using a fast and cost-effective solution.
Terefil® Provides Alternative to Gravel Raft to Address Soft Soil Beneath Auckland Substation
Install three lightweight concrete rafts to support the substation switch room, transformer building, battery banks, retaining wall and part of the driveway, without increasing load on the soft clay ground beneath.
Filling holes and voids under commercial and industrial sites
Commercial and industrial settings often have unique requirements and restrictions when applying a hole or void filling solution. Mainmark’s void filling foam and engineered resin solutions can quickly address site problems that arise during excavation and construction works, or emerging issues in existing warehousing, manufacturing, service and processing facilities. Minimising downtime to maximise productivity is often the most important business objective. Mainmark utilises application methods and materials which cause the least disruption to the working environment, while adhering to the highest safety standards.
Concrete slabs
Unstable soils leading to voids forming under concrete can result in cracking and subsidence of the slab surface. An uneven floor can seriously impact the regular function and safety of heavy machinery, and creates a hazard for vehicles and foot traffic. Void filling solutions such as Teretek® resin injection are applied in a process similar to keyhole surgery. Mainmark technicians can drill injection points to inject the expanding polyurethane resin mix through small injector tubes. The components mix together and expand, strengthening the ground by filling air pockets and larger voids, while also re-levelling the concrete slab. This method is quick and non-invasive, and requires no demolition or excavation.
Landslip repairs and retaining walls
Landslips and subsidence put pressure on building site retaining walls, posing a significant risk of wall collapse if ground conditions become too unstable. Whatever the cause, emergency remediation will often be needed to ensure site safety and minimise damage to adjacent buildings. Solutions such as Terefil® lightweight cementitious fill, and Teretek® resin injection, can benefit engineers and builders when there is a need to backfill, remediate or support a retaining wall quickly without compromising its structural integrity or strength. Terefil, which is available in permeable or impermeable form to suit specific site conditions, is ideal as a backfill for retaining walls during construction or after a new wall has been built. It forms a stable block without disturbing or redirecting natural water flow and its light weight minimises pressure on the wall when compared to heavier granular fills. Once in place, Terefil can withstand heavy loads, including large machinery and vehicular traffic, to allow construction works to continue.
Fuel tanks
As a large hole filler, Terefil® can be used to safely decommission abandoned underground fuel tanks on industrial sites. Easily pumped from above ground, the solution economically fills high volume tanks before they are removed and transported off site.
What causes holes and voids?
Holes are often dug in mining, building, and infrastructure works, while voids may develop over time due to leaks and weather eroding sub-soils underneath a structure. Something as simple as a leaking pipe may wash away surrounding earth, creating voids (or an empty space) around the pipeline. Filling holes and voids ultimately aims to stabilise mines, tunnels, buildings, bridge approaches, bridge abutments, and other operating or decommissioned structures.
Likely causes:
Construction holes and excavation |
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Earthquake and seismic activity, often resulting in liquefaction |
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Erosion |
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Flooding |
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Joints in culverts |
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Land slippage |
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Leaking pipes washing away sub-soils |
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Abandoned tanks and pipelines |
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Mining and commercial operations |
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Poorly compacted void fill |
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Water ingress |
How to fix holes and voids
Mainmark has a number of void fill solutions such as polyurethane and cementitious grouting. We assess each situation to determine the best course of action and the best material to use. Smaller voids in underground rock strata are generally filled with a void filling foam or concrete void filler; a material like urea silicate or polyurethane resin that not only fills the void but also ‘glues’ the surrounding rock together.
When greater supportive strength is required, such as for retaining wall backfill or large voids, Mainmark’s Terefil® solution can be applied. A lightweight polymer modified cementitious-based void fill material, Terefil can be used for massive voids that require filling quickly and economically. This large hole filler material can also be used across a variety of void-filling situations, including retaining wall fill, abandoned fuel tanks, pipelines, and manholes, voids behind seawalls, and quick-support, easy-flow backfill for service trenches.
In areas where sandy soils dominate, a multi-stage approach may be required to fill voids safely. Large washouts and holes caused by coastal erosion and flooding can be stabilised using permeation grouting, before void filling commences.
Benefits of Mainmark’s methods to fill holes and voids:
Stabilising worksites in building and construction efficiently to minimise downtime |
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Addressing land slippage around facilities for a safer working environment |
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Filling abandoned underground fuel tanks safely and economically; tanks can later be removed, transported whole and cut up safely |
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Filling pipelines uphill or downhill without the filler spilling out |
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Retaining wall and wing wall backfill |
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Strengthening the foundation ground under buildings and other on-ground structures |
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Stabilising access routes |
