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BFS18 Vibrolance with the Bottom-Feed System working on a 4500 linear meters of stones columns

4500 linear meters of stones columns for the construction of a 5 storey building for the Grenoble University
Excavator Mounted BFS18 Vibrolance in action
The project was conducted by FRANKI Fondations, specialized in deep foundations, a part of FAYAT Group. FRANKI has used PTC VL18BFS Vibrolance in order to install 850 stones columns for the reinforcement of the ground required to support the 5 storey university building.
The BFS system allowed the gravel to be directly fed at the bottom of the stone column without removing the Vibrolance. This technique offers better quality as a consistent diameter and no risk of discontinuity.

The 850 columns has been installed with a grid of of 1.5m and a 4m to 6 m depth .
Thanks to its Bottom-Feed System, the productivity of the Vibrolance was higher than a basic top feed system. For this jobsite, productivity attained 150-200 linear meters a day which was a positive result for the customers.

Specially designed to be mounted on hydraulic excavators, the VL18 BFS was mounted here on a 35t KOMATSU PC350HLC on rent. Costs were optimized and investment reduced.

Load Test Result:

Franki Fayat has contracted an independent firm to perform a load test on the ground after treatment.

The stone columns treatment obtained a very positive results at a static load test, the soil settlement was limited to 16.32mm, largely less than the designed criteria of 25mm.

Different Advantages of the PTC VL18 Vibrolance:

  • This Vibrolance excavator mounted as an equipment for ground improvement can be used in many different conditions: exiguous jobsites, city centers, embankments, riversides … a jobsite that has a special conditions need (city center, sensible soils conditions etc…)
  • Stone columns with Bottom Feed are well adapted for soil conditions of clay, slit and sands with treatment depth up to 8m. The cost of using this system allowed company of any size to have the equipment as investment is limited, productivity is high and maintenance limited.