Situated on the River Medway in the historic fishing village of Lower Upnor, the project involved a man-made slope adjacent to the road showing significant signs of instability. This was caused primarily by over filling at the top of the steep slope. Our solution to stabilise the slope involved an engineered berm at the base to prevent further base heave as well as the installation of a buttressed contiguous bored pile wall.
Projects
Galleons Way
Fixing significant slope instability
Services
Sector
Client
Taylor Wimpey SE
Engineer
Knapp Hicks
Contractors
O’Hallaran & O’Brien
Location
Kent
Duration
12 weeks
Slope Stability: Fixing Failures
Earlier remedial action, involving ballast bund bags at the base of the slope, had failed following significant rainfall, causing shear tears and deep fissuring within the slope. Further rainfall continued the shear failure through water ingress in the fissures, resulting in instability that caused the displacement of the bags onto the pavement and trees, sliding down the slope around 100 metres.
Our solution involved the installation of a 26 metre plan length of 600 mm CFA piles to a depth of 11 metres, reinforced with full depth 10H40 bar cages. The engineered berm provided an access platform for our Klemm 709 14 tonne piling rig which was required to install the contiguous wall piles. Due to the piles penetrating the Thanet Sands at depth, it was necessary to use a cage vibrator to assist with cage installation.
Capping Beam: Thinking Ahead
A capping beam designed to span between the buttresses was installed with additional anchorage ports cast at a 20° rake to facilitate future anchor installation in the event this would be required.
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