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When building on many sites with poor ground conditions the most economical approach to the foundations is to improve the bearing pressure rather than attempt to by pass the weaker soils with piled foundations.
Ground Improvement systems can typically be 50% of the cost of a piling scheme but, more importantly, further cost benefits are provided by adopting simpler sub structures and in most cases the lack of spoil generation.
Keller Geotechnique offer a range of ground improvement systems that include Soil Mixing and Compaction Grouting.
The choice of system is determined by the particular ground conditions, design loads, the size of treatment area and site location.
A ground improvement system that is purpose designed for the insitu treatment of very soft clays [typically >20kpa], silts and organic soils such as peat.
Keller's insitu mixing processes include dry mixing of cement/lime powder binders and wet mixing using cement based slurries.
Compaction Grouting
A highly effective ground improvement system that is frequently used for the deep insitu treatment of chalk swallow features and collapsed mine workings.
Compaction Grouting can also be used to control settlement of granular soils caused by tunnelling operations and to underpin buildings.
And of course... Piling
Driven Displacement Piling
Highly efficient, the Keller Driven Displacement Pile is designed to make maximum use of the available skin friction and end bearing potential of the surrounding soil. It is capable of achieving high working loads in a variety of weak subsoil conditions, regardless of water table.
Robust, the construction method used is ideally suited to piling 'brownfield sites' where obstructions can frequently create programme and cost control problems. The Keller Driven Pile system can frequently drive through obstructions that would create problems for other piling techniques.
Environmentally Friendly, apart from the key benefit of not producing spoil, the construction method produces a pile that is tightly interlocked with the surrounding ground giving a reduced risk of vertical migration of contamination.
Keller's Augercast Continuous Flight Auger (CFA) piling system provides a quiet low vibration form of piling that is ideal for providing foundation support in built-up or environmentally sensitive areas.
Keller's CFA rigs can construct piles in most soils including sands, gravels, silts, clays, chalk and weak bedrock, in high water tables without the need for temporary support systems.
Where headroom is limited or the site is confined structures of all types can be founded on Minipiles and our range of rigs for difficult access sites is unrivalled.Similarly our obstruction drilling expetrise,such as through quay walls or old foundations leads the industry.
At the other end of the scale... where large diameter piles are constructed in granular soils grouting tubes can be attached to the reinforcement cages enabling base grouting to enhance pile capacity. Some of the country's tallest structures are founded on piles Base Grouted by Keller.
