In metropolitan Sydney, Australia, AMC CIVIL MUD XTRA™ significantly improved trench wall stability and dispersion, assisting construction underneath a major arterial road. The bentonite free mud system minimised fluid loss and improved productivity, allowing the project to progress without interruption to surrounding road conditions.
Challenge
AMC’s client was constructing a series of diaphragm walls to support the ground formation leading into a tunnel for a new metropolitan light rail system in Sydney, Australia.
The diaphragm walls consisted of 63 interlocking panels ranging from 6m long and 18m deep and was being built below a major arterial road. On completion of the first trench, high seepage was experienced, resulting in the trench collapsing and requiring filling and re-digging.
The geological profile of the site included a variety of loose grain sands, peat, basal alluvium and sandstones and the possibility of igneous dykes. While a bentonite system would ordinarily be used in these conditions, the client specified the requirement for a bentonite free, polymer mud system to ensure trench wall stability and to
control dispersion, enabling fluid to be available for immediate re-use. AMC recommended several specialty products, such as AMC CIVIL MUD XTRA™, AMC SHUR SEAL™ and MAGMA FIBER to accomodate.
Results
- Minimised fluid loss, resulted in a significant reduction in fluid costs
- Improved construction productivity – five walls completed every six days
- Trench walls stabilised, no further collapse experienced
- Fluid volume maintained to meet construction demand controlling the fluid loss
- Successful use of polymer fluid system – no bentonite
- Recycled fluid free of cuttings.