Herne

Combined cycle power station

777 Frankipiles NG® for the foundations of a power station site in Herne

Foundations for a combined cycle gas and steam power plant

The Herne 6 power plant forms part of the Herne combined heat and power (CHP) site. The plant was constructed as a combined heat and power (CHP) facility and generates electricity as well as district heating for the region. Pile foundations were required for the power plant structures in order to transfer the structural and plant loads to load-bearing soil layers.

Pile load tests in preparation for the foundations

Before the actual foundation work began, a programme of pile load tests was carried out in June and July 2019. This involved dynamic pile load tests on two test piles, as well as static load tests in both vertical and horizontal directions. The investigations served to verify the required bearing capacity analyses and formed the basis for the design of the pile foundation.

777 Frankipiles NG® for load transfer

A total of 777 Frankipiles NG® were manufactured for the project. The piles were driven to depths of around 16 m into the marl and are responsible for transferring the loads from the power station structures. Frankipiles NG® are a type of displacement pile system and are used for foundation works where loads need to be transferred to deeper, load-bearing soil layers.

Documentation of pile quality

Once pile fabrication was complete, pile integrity tests were carried out. The tests served to document the piles produced and to inspect the pile bodies. The tests complemented the load tests carried out previously and formed part of the quality assurance process for the foundation works.

Savings on concrete and transport through adaptation of the foundation design

During the foundation planning phase, various foundation options were examined. Compared with an alternative originally considered, the foundation concept implemented resulted in a reduction in concrete requirements of around 6,000 m³. As well as this, around 800 transport journeys for concrete deliveries and for the disposal of drill cuttings were eliminated, as the Frankipile system used is implemented as a displacement pile method and no drill cuttings are removed during pile fabrication.

Foundation for the power plant facilities

The installation of 777 Frankipiles NG® laid the groundwork for the construction of the Herne 6 power plant. The pile foundation forms the basis for load transfer for the technical installations and structures at the power plant site.