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Soil Liquefaction

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Does your Trakway supplier understand Liquefaction? Chances are, they will not have even heard of it.

As a physical explanation, soil liquefaction is 'a phenomenon whereby a saturated or partially saturated soil substantially loses strength and stiffness in response to an applied stress' - essentially the main reason my father started this industry in the 1960s.

  • Liquefaction
  • Soil mechanics
  • Liquefaction

Safety Risk

The transportation of heavy loads or the erection of temporary structures carries the risk of changing the mechanics of the ground beneath, even over tarmac or concrete surfaces. In general, soil is 45% mineral, 5% organic and 50% voids - half of these voids are occupied by water or gas and easily subject to ‘soil liquefaction’ when there is force applied. This causes the substrate’s molecules to lose friction, resulting in ‘shear strength’ failure. A lack of understanding this phenomenon can put your plant, property, personnel and the public at risk.

Geotechnical understanding

Ground engineering is a complex topic and accidents can be the result of inadequate experience of geotechnics. The surface of the ground may appear stable in most instances but the layers beneath the surface and the probability of buried utilities can pose further risks to your operations.

Cone penetrometer

Geotechnical testing

Live is the only ground access company who carry out CBR Penetration testing (California Bearing Ratio). Where necessary, these tests enable us to evaluate the mechanical strength of the ground and collect data to assist in our recommendations.

In addition, our A-Plant sister company, Opti-Cal can provide Ground Penetrating Radar (GPR) equipment to detect underground utilities. These include non-metallic risks like plastic, concrete and terracotta pipework and enable the mapping of underground infrastructure to identify further risks they may pose to the ground’s stability.

GPR

Calculating a safe solution

To mitigate serious risks, we can adopt a 7-point formula to provide an exact engineered solution for every part of your site, this calculation will involve:

  1. Route-to-site survey
  2. CBR soil strength testing
  3. Topographical survey
  4. Vehicle axle weights and point load calculations
  5. Traffic volume calculations
  6. Duration and frequency of traffic forces
  7. Met office weather predictions
Transmission Line Height Measurement

Engineered solutions

Once surveying is complete, we calculate the scenarios using the data collected and design a configuration of specific products to provide an exact solution. Some systems are combined together to deflect heavier loads, some offer increased tyre grip on steeper inclines and others are configured to virtually ‘float’ on saturated marshland (See below).

There are many scenarios to consider for a safe solution. Public safety cannot rely on companies offering a 'single product/roadways-to-go service', with little understanding of what might happen after the product is installed.

Highway Bridge SPMT

Experience

You may be surprised to hear that there is no industry qualification or ‘manual’ for ground access solutions; even the California Bearing Ratio is an American wartime measurement that has no hard rules of application. A safe solution relies on a portfolio of certificated products and a very high level of ground access experience.

LIVE’s Engineers have decades of experience in extreme scenarios from delicate ground protection to the assistance of abnormal loads across challenging terrains (See case studies). Today we operate our own LVQ (Live Vocational Qualification) through our own dedicated academy facility and training team. This enables us to continue to pioneer the industry with safety as an absolute priority.

Trakway incline

Conclusion

Put in simple terms, the industry’s own classification of light, medium and heavy-duty access applications can be very misleading. For example, a 200t capacity crane over marshland could be considered abnormal loading and clearly heavy-duty, however, light vehicles can also require a heavy-duty solution. Hundreds of cars travelling across a single route can often result in shear strength loss by drawing water to the ground surface, making it unstable.

It is therefore essential for any temporary access company to consider the absolute basics when offering their service; load calculations, changing ground conditions and the proposed number of passes, as a minimum concideration when proposing their solution.

Temporary roadway companies have always presented costs based on a panel rate per-week, maybe an easy way for customers to compare proposals… however, the cost for the service LIVE provides isn’t based just on the amount of Trakway, Bridging or Fencing you require, it is the real value of our experience, knowledge and accurate insight we obtain in order to eliminate risk - ultimately it is the safety and success of your operation that you are investing in.

So, if your supplier has never heard of Liquefaction and our estimate comes in just £1 more, per-panel-per-week, there's a very good reason why that is.

Beach access Trakway

So, that's a little more about why we love what we do - and why we think we are a valuable investment to your operations, at every technical level. Thanks for reading, if you'd like to know more about the science behind our services, take a look at our other blog posts below...

Stay safe folks,

Dale

Dale Robinson

Live’s MD, Dale Robinson is a veteran of temporary access. The son of industry pioneer John Robinson, Dale is hailed as one of the most experienced engineers in the industry. Having started his career literally at grass-roots level in the 80s, he quickly developed through the ranks and became the MD of Eve Trakway (Now Live Trakway) in the 1990s.

He continued to pioneer the industry, introducing the service into Europe, establishing 3 new divisions and moving on later to build two other UK trakway businesses.

Dale was instrumental in many firsts in the industry, for example, the invention of the aluminium box panel (the industry standard today), the ‘steerable’ cornering panel, and the concept for the 8km Super-Fortress fence for Glastonbury Festival. He spent his early years with his father designing access solutions for many challenging applications including aircraft and rail recoveries, helping move ancient buildings in one piece and assisting 200t plant across saturated marshland. Dale has consulted with industry as far as Australasia and worked with European defence agencies and the UK’s own Defence Evaluation and Research Agency during the mid 1990’s, informing the designs for military access applications.

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