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Stabilising and reinforcing sea defence and ground near car park
Keller was contracted to help stabilise and reinforce the sea defence and ground in front of a council car park in Lyme Regis that had been affected by years of corrosion. Typical anchors would not generate the load required, so Keller elected to use its SBMA anchors which allow multiple anchors to be installed in the same bore. Access to drill the bores was hampered by
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SBMA anchors reinforce sea defences and ground at car park in Lyme Regis
Due to years of corrosion, the existing sea defence and ground in front of a council car park in Lyme Regis needed to be stabilised and reinforced.
Balfour Beatty Construction Services designed a new rotary piled wall to solve the problem, but the design required anchors to take 545kN axial loading located in the mudstones and limestones ranging from extremely weak to medium strong.
Challenge
Typical anchors would not generate the load required, so Keller elected to use its SBMA anchor which allows multiple anchors to be installed in the same bore. Access to drill the bores was hampered by the requirement of a narrow platform for the working area so two crawler-based rigs were used, drilling cross-masted at the anchor locations.
Due to the ground conditions also indicating a shear zone within the free length, concern was raised regarding the chosen water flush installation method.
Solution
Keller's design consisted of a four-stage SBMA with four 3m fixed lengths, and a three-stage SBMA with three 3m fixed lengths with a minimum 24m free and up to 33m free length.
Keller used its dedicated anchor installation crawler-mounted rigs and, to prove that the chosen proposed method of water flush would be adequate, installed three trial anchors using different drilling techniques and tested each to the required loads. All anchors were tested to BS8081.
