Descriptions
The gauge consists of two end blocks with a tensioned steel wire between them. The end blocks can be attached by either arc welding, bonding or groutable anchors to steel or concrete.
Around the wire is a magnetic coil which when pulsed by a vibrating readout or data logger interface plucks the wire and measures the resultant resonant frequency of vibration.
As the steel or concrete surface undergoes strain the end blocks will move relative to each other. The tension in the wire between the blocks will change accordingly thus altering the resonant frequency of the wire.
Case Studies
Severn Valley Landslip, Ironbridge
The River Severn flows through the Ironbridge Gorge which is located to the south of Telford in Shropshire and is a World Heritage Site. The Gorge is thought to have originated some 10,000 years ago and is deeply incised in rocks of the Upper Carboniferous and Silurian age, which are prone to land sliding. There have been a number of failures through its history. The valley sides rise steeply from 40m at river level to over 140m on the plateau above.
A recent slip had occurred in the Halesowen Formation. This area is particularly susceptible to movement as it includes more silty strata and less sandstone than elsewhere. Buildings and roads were affected by the landslide.
Considerable investigative work was undertaken by Telford and Wrekin Council on this landslide to develop appropriate management plans to anticipate and mitigate the effect on the land usage. This included ‘stitching’ strategic locations within the area of failure using tubular steel sections which were placed into the hillside and then filled with concrete.
Severn Valley Landslip, Ironbridge Case Study
