A storage building has been constructed in Hässleholm, Sweden. The ground needed stabilization as the geology presented sand and friction soil in different layers above the bedrock.
Wassaras jet grouting hammer made the operation possible as it combines a water-powered W100 DTH hammer with a grouting monitor.
Building on difficult geological conditions
Bergendahl Foods in Skåne, Sweden, is expanding their storage capacity by constructing a new 32 meter high automated storage building in Hässleholm. The storage will have a total area of 4 000 m2 and host up to 18 000 pallets. Decision was made that the concrete floor shall be 1 m thick so it can withstand a load of 10 800 metric tons. The ground conditions required stabilization as the formation above the bedrock consisted of sand and friction soils coming in different layers.
The ground stabilization
A total of 288 columns were needed to stabilize the ground. Since the worksite is surrounded by buildings, vibrations and settlements must be kept at an absolute minimum in order to avoid damage and disturbance.
A decision was made to form jet grouted columns, the only soil stabilization technique that would work equally well in plastic clays as in granular materials, although compressive strengths and load capacity are typically higher in granular materials.
Since the formation included boulders, the drilling sequence must be performed with percussive drilling technique. Pre-drilling with air-powered DTH was not an option as it would require separate rigs for the grouting and drilling processes, and risk ground settlements.
The consultant WSP and the contractor PEAB concluded that the water-powered drilling was the most appropriate technology for this project.
|DTH Hammer||Wassara Jet-grouting hammer W100 JG|
|Drill bit||Ø 153 mm|
|Drilling fluid||Clean water from public source|
|Drill tube||Duplex drill tube, 114 mm|
|Water pump||WASP 150 Diesel|
|Jet-grout pump||Tecniwell model TW352|
|Borehole length||5.5 meters in average|
|Scope of drilling||1 600 meters|
|Geologic formation||Sand, friction soil and rock|
|Project time||May-July 2013|
See our featured Case studies below to learn what real world Ground Engineering-projects our technology as been a part of.