Soft spoil is a term often encountered in construction and piling projects, but if you’re not in the industry yourself, it’s a term you may not have heard before. Essentially, it refers to the soft, loose material generated during excavation or piling activities, which can include soil, clay, silt, or other fine sediments. It’s harmless on its own, but when it comes to mini piling projects, it can have significant implications for both project timelines and costs, requiring careful management to avoid delays or complications. Thankfully, we’re more than experienced enough to deal with them here at Vxcel Piling!

So, here’s what you need to know.

What soft spoil is and why it matters

Soft spoil is the by-product of excavating through softer ground strata, typically during the early stages of a piling project. Unlike firmer materials such as rock or compacted soil, soft spoil is less stable and more challenging to handle. Its characteristics can include:

• High moisture content, which makes it prone to slumping or spreading when stockpiled.
• Low bearing capacity, which increases the difficulty of supporting heavy equipment or structures on-site.
• Propensity for contamination, which means it can potentially mix with water or waste materials during construction.

The challenges associated with soft spoil aren’t just limited to its physical properties. Its presence often impacts project planning and execution, leading to potential increases in both operational complexity and costs. For instance, it may necessitate additional transport or disposal measures, or specialised equipment to manage the material.

The role of geotechnical surveys in identifying soft spoil

Geotechnical surveys can often play a pivotal role in identifying soft spoil materials and enabling strategies for managing them effectively. A geotechnical survey typically involves drilling boreholes and conducting soil sampling to assess the composition and condition of the ground. These surveys can highlight areas where soft spoil is likely to occur, providing key data on:

• Depth and distribution of soft soil layers.
• Moisture and density levels, which affect spoil stability.
• Potential contamination risks from nearby land uses or water sources.

With this information, it becomes possible to ensure that the equipment and methods chosen for the project are suited to the site’s specific needs.

Methods to manage soft spoil during piling

Managing soft spoil effectively is a crucial aspect of successful piling operations. There are a variety of techniques that can be employed to minimise its impact on the project. For example, stockpiling and containment – soft spoil is often stockpiled temporarily before disposal or reuse. This requires careful containment measures, such as bunding or geotextile covers, to prevent the material from spreading or becoming waterlogged.

Another key measure is stabilisation. Soft spoil can sometimes be stabilised using additives like lime or cement to improve its load-bearing properties. This allows the material to be reused on-site, reducing disposal costs and environmental impact. There may also be opportunities for recycling it, using soft spoil in landscaping or as fill material, provided (of course!) that it meets safety and regulatory standards.

The impact on piling equipment and techniques

The presence of soft spoil often requires adjustments to the equipment and techniques used during piling. Conventional methods may not be suitable for softer ground conditions, and modifications may be required to ensure stability and precision.

For example, rigs designed for handling cohesive soils may need to be equipped with augers or casing systems that are better suited to managing soft materials. Additionally, spoil removal processes may require adaptations, such as vacuum extraction systems, to handle the loose and often waterlogged material efficiently.

Selecting the right approach not only mitigates delays but also helps maintain the safety and integrity of the project. The cost implications of specialised equipment must be weighed against the potential risks of inadequate preparation.

Now, this is just a quick rundown of the essentials, and it’s worth bearing in mind that it’s not necessarily a guarantee that you’ll have to deal with them for your own project! And of course, if you do ever need any advice or assistance with a potential issue, you can always ask our team at Vxcel. With over a decade of experience here at Vxcel, we’re here to make every aspect of the project go smoothly, and we’ve got all the in-house expertise and equipment we need to get it done. To find out what we’ve achieved for previous customers, feel free to take a look through our case studies!

And of course, if you’ve got any further questions about mini piling in general, then you’re in exactly the right place. just give us a call on 01254 314010, and we’ll be happy to see how we can help!