Sadlers Farm – Soil nailing on the A13

Works on the Sadlers farm Junction Project continue apace and making the most of this unseasonal spell of good weather.

On the A13 – on the stretch between Church Road Bridge and Pitsea Flyover the works are focussed on widening the embankments for the new increased width of highway.

Between Church Road Bridge and the junction the road is also being widened but to facilitate this the existing cutting needs to be widened which is not quite as easy.  The technique being used is call soil nailing.  Essentially the ground is being dug to a slope which will not stand up (in the long term) on its own.  To provide long term support a series of soil nails are put in.

Soil nails are basically long steel bars cemented into a sloping hole deep into the ground behind the face.  A big plate and a facing mesh is then used to support the cut earth face and transfer the loads into the nails and down into the ground.  It is a neat solution and commonplace in civil engineering today.

To find out more about soil nailing visit Keller geotechniques website here or read up on Wikipedia here.

The new slopes finally have topsoil put on them but because the slopes are steep the topsoil wont stay on the face on its own.  To keep it there a plastic ‘honeycomb’ system is secured to the face and the voids in it are filled with toposil. Once seeded and the grass grows the black plastic all but disappears.

A few photos of this are included below.  A few more can be found on my Picasaweb photo sharing website here.

Comments and questions welcomed as always.

Works to widen the existing embankments near Pitsea Flyover
Soil Nailing to widen existing cuttings east of Church Road Bridge
Close up of the soil nailing plant and equipment
Piles for the north abutment for the new Church Road Bridge

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