UK GROUND improvement firm Vibro Foundations has developed a stand-alone vibro replacement poker, claimed to be more flexible and economic than standard mast-supported equipment.
The 9m tall bottom-fed VibroStitcher is fixed to the arm of a standard excavator so it can be operated on more sites than larger dedicated rigs, the firm said.
Only the 5t poker needs to be delivered to site and its integral two section stone chamber can be fed - without being lowered to the ground - by any loader bucket.
Vibro Foundations operations manager Alec Courts said the average UK ground vibro replacement treatment needed only 3m to 5m deep stone columns. At up to 20m tall, masted rigs designed for the international market and its generally deeper soil strengthening needs, are not ideal for this.
Computer instrumentation helps ensure verticality and monitors the entire operation. Courts claimed that average stone column completion rates match those of any dedicated rig.
The machine's forward reach even allows steep-sided rail embankments to be probed and their foundations strengthened.
Masted pokers require more benching into the embankment to provide machine stability.
Further developments include designing a family of differently rated pokers, offering efficiency over an even wider range of ground conditions and in situations vibration could damage surrounding structures or their contents.
Lancashire-based Vibro Foundations was set up earlier this year following French geotechnical contractor Soletanche Bachy's purchase of a 70% stake in German ground treatment firm Vibroflotation Group.
A 30% share remains with the founder owners of Vibroflotation, the Degen family, who pioneered vibro poker design from the early 1930s. The new firm is a subsidiary of the group's UK division Bachy Soletanche.