Keller is using its newest instrumented rigs to improve quality control of ground improvement work that it is delivering for a scheme to upgrade a single line rail route between North Oxford and Bletchley.
The ground improvement work on the approach embankments forms part of an £87M project for Network Rail and Chiltern Railways being undertaken by the Carillion Buckingham joint venture.
Keller’s is installing 3,500 vibro stone columns as part of the project that includes building a new 1km section of railway to connect the Bicester Town to Oxford line to the Chiltern main line, widening the existing track bed and doubling of track over 18km of railway to increase the line speed to 160kmph. Keller is treating beneath new embankment approaches before construction of new over-bridges, under-bridges and footbridges around Bicester, which will be built on alluvial clays and stiff Oxford Clay by the JV.
A combination of bottom feed stone columns is being used beneath some embankments and top feed columns below others to reduce settlements. The contract will last six weeks.
Use of rig instrumentation is enabling scheme designer Atkins to check power consumption and depth of refusal in real time.
Keller business development director Derek Taylor said: “We believe we are the only geotechnical contractor offering real time recording of column construction data which is visible in the office direct from site by way of modem transfer. At these sites it is important that the client has prompt access to data to ensure expected depths of treatment are attained and to target load testing.”