Trench Bedding Machine


Overview

Typically, pipelines used for oil, gas and water, as well as large electrical and communication cables for major infrastructure projects, can cover distances from half a kilometre to hundreds of kilometres. The route taken by these pipelines and cables inevitably transverses all types of country, conditions and soil types. In most cases, these pipes and cables must be placed below the surface to minimize exposure to the natural elements and protect the environment.

Current technology uses large machines such as Trenching Systems Australia's Tesmec chain types to dig the trench. The trench is cut up to 1100mm wide and up to 2400mm deep through all types of soil and rock. These trenching machines excavate the soil and rock from the trench whilst cutting it. In some cases, when the earth is rocky, the trench base can be left rough and uneven. It then becomes necessary to 'bed' the trench base with a layer of sand up to 150mm deep prior to laying any pipe or cable. This creates a soft, even bed for the pipe or cable to lay on and ensures longevity and stability of that product.

Existing Practices

Currently, the process of bedding a trench is carried out using either skid steer loaders (or large articulated type loaders) or excavators to bucket imported material into the bottom of the trench. All these machines require an operator to dump the imported product from the bucket. The machines are continually stopping to refill and stopping to move further along the trench. The dumping action means the material is inevitably inconsistent in nature and requires a labourer in the bottom of the trench to level the material to the required thickness. Skilled skid steer operators with a labourer to level the product can bed around 100m of trench with 100mm of sand in around 2 hours.

The Safety Issue

A trench by definition is a narrow (and sometimes deep) chasm in the earth. In certail soil types, the labourer is placed in a high risk environment that may lead to injury or death if the trench wall collapses. This may be caused by machines working overhead or, even if the machines are not currently in use, caused by the machine running close to the trench edge whilst filling. It is very difficult to see into a narrow trench so visibility also becomes an issue on construction sites where staff and vehicle movements are frequent.
The protection of the labourer is currently achieved by having safety regulations in place that require additional observers, safety platforms, trench support frames and procedures designed to offer the best practices of protection.

Added to this is the fact that the job of the labourer is to level the material using hand tools. He/she will be invariably bending over and pushing or pulling heavy material that could cause severe back strain and injury of not properly executed. Back Pain or Spinal Injury is one of the largest causes of lost time due to injury in the construction industry.

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