DAWSON WAM has installed a new sheet piled wall as part of a flood defence programme on the River Chelt in Cheltenham, Gloucestershire.
The river has flooded several times in recent years, putting homes and businesses at risk.
The Environment Agency scheme, designed by consultant Halcrow, calls for the widening of the river culvert to allow greater water flow capacity and construction of an overflow connected to a bypass culvert for times of high flow. The main contractor is Jackson Civil Engineering.
Ground conditions on the river bank were fill over sand and gravel, clay and mudstone. Because of the geology, and to reduce noise levels during piling, a 450mm diameter auger was used to break up the ground along the line of the wall running along the riverbank.
The 92m long wall is made up of 153, 9.5m long LX25 sheet piles, pitched in groups of 15 to 20 and then vibrated into place in groups of four. Dawson used its TM18-22 telescopic rig to carry out boring and driving on its £40,000 contract.