Edelhöfe
Helmstedt
Helmstedt, Germany / 01.2018 - 12.2019
A residential and commercial complex with up to six storeys was built on a plot of approximately 4,700 m² in Helmstedt. The building site is situated on a former car park and borders a historically used area to the south. Soil investigations revealed fill material as well as underlying layers of sandy silt, sandy clay, peat and lignite. Subsoil improvement was therefore required to support the planned structural loads. PORR special civil engineering carried out the work using vibro replacement.
Facts & Figures
Company
PORR Spezialtiefbau GmbH
Type
Subsoil improvement
Runtime
01.2018 - 12.2019
Vibro replacement for a residential and commercial building.
Subsoil improvement using vibro-compaction columns
Based on the subsoil and foundation survey, subsoil improvement was carried out using vibro-compaction columns. The aim was to improve the bearing capacity of the subsoil for the foundations of the building complex. A total of 341 vibro-compacted columns were constructed, with depths ranging from 4 m to 6 m as well as a column diameter of 65 cm.
Vibro-compaction method for different soil layers
A vibro-compactor was used for the work, which was driven into the ground under vibration and contact pressure. Once the planned depth had been reached, the vibrator was gradually withdrawn whilst aggregate was introduced. Repeated insertion and withdrawal of the vibrator created compacted columns from the introduced material. Whilst cohesive soils were displaced laterally, non-cohesive soils were compacted by the vibrational energy introduced. The method was adapted to the varying ground conditions at the site.
Subsoil comprising backfill, peat and lignite
Beneath the paved surface of natural stone paving, there was predominantly sandy backfill. Beneath this, layers of sandy silt, sandy clay as well as organic soils such as peat and lignite were encountered. The subsoil improvement was designed to transfer the structural loads into the deeper, load-bearing soil layers and to optimise the foundation conditions for the new building.
The basis for the new development
By constructing 341 vibro-compaction columns, PORR special civil engineering laid the groundwork for the realisation of the ‘Edelhöfe’ development in Helmstedt. The subsoil improvement formed the basis for the subsequent construction of the residential and commercial complex.