The works had to be completed before the danger to the houses became too great. The difficulty in the project was that the slope had a severe gradient to the slope and the ground itself was fractured, weakened and extremely muddy meaning that large plant would not be viable to complete the project. 

Therefore, Condor proposed the use of our Husqvarna DXR 310, a brock with a drill rig attached to it to complete the soil nailing. The Husqvarna is more agile and lightweight compared to other plant used for soil nailing. The Husqvarna has the capability to install soil nails to the depth required without the risk of slipping like the larger excavators. 

 

The works had two phases. 

 

• The stone wall holding up Scout road showed signs of subsidence and movement, requiring the installation of soil nails with pattress plates with the addition of diamond cored weepholes. 

 

• The slope contaminated with asbestos required the installation of soil nails which were then covered with a steel mesh affixed by plates and nuts over the anchors. 

Phase one had to be completed first due to Scout road being an important through road connecting Halifax to outlying villages including civilian and commercial traffic. The wall underneath the road showed signs of bulging and fracturing, firstly we diamond cored through the face of the wall in the pattern designed to ensure no damage to the face would occur once soil nailing operations began. 

 

The wall was pinned using soil nails installed using grout flush, the nails were drilled to the desired depth and grout pumped until operatives saw a return of grout thus showing that the entire soil nail had been filled with grout. 

 

Once the grout had cured, pattress plates were placed over each individual soil nail and the nut tightened using air powered means, this applies pressure onto the wall stopping any further bulging/movement. The final measure required was to core diamond drill weepholes in the bottom of the wall. This is essential as the main cause for this subsidence is the build up of water over time. The weepholes allow the water to drain out of the wall ensuring no build up of water behind the wall. 

Phase two of the works was the pinning of the asbestos dump on the hill above the row of the houses on Scout Road. As stated earlier the ground was sodden and laced with all types of asbestos as well as having a steep decline. Therefore, the Husqvarna DXR 310 had to be used to complete the project. 

 

Condor determined that a series of winch points should be installed on the crest of the slope and the Husqvarna was to be secured via winches at all times when operating on the slope ensuring that the Husqvarna could not slip when drilling the soil nails, also the winches would help with moving the Husqvarna on the difficult terrain, improving the safety of the works. 

 

Soil nails were installed from the crest down to the toe of the slope using grout flush, this was needed as via site investigation it was found that the slope was fractured and had a number of large voids. Grout was pumped down each nail until a return was seen. Showing that the voids were being filled thus increasing the stability of the slope. 

 

The slope was then covered in a flexible steel mesh which moulds itself to the contours of the ground, the mesh goes over the installed soil nails and then secured to the ground via plates and nuts, this stops the ground from being able to shift and move.