Germany - Research and development services and related consulting

Description

The subject of the call for tenders is a framework contract. The framework contract mainly comprises hydraulic investigations of mass transport in the ERAM, which are an essential part of the long-term safety analysis. In these calculations, both gas and solution transport as well as the storage capacity of cavities, rock and building materials are considered. For these calculations, the hydraulic properties of the materials involved and their composites must be parameterized. These investigations including test specimen production and conditioning are to be covered by this framework contract.
According to the plan for the decommissioning of the ERAM /1/, the existing cavities of the ERAM mine workings will be largely backfilled with a flowable salt concrete. These backfilling measures will, among other things, transfer loads resulting from rock pressure into the rock mass. In addition, subsidence of the surface and dissolution of potentially inflowing saline solutions with the rock are limited. Furthermore, the stability of the mine workings and the condition of the geological barrier are maintained.In selected drifts, the construction of drift seals made of a magnesia construction material (MgO construction material) is planned to separate the emplacement areas from the rest of the mine workings and to impede solution movements over a sufficient period of time. For the backfilling of boreholes, a similar MgO construction material adapted to borehole backfilling is to be used. If necessary, other construction materials such as a MgO shotcrete or bitumen/asphalt may also be used. Therefore, further comparative investigations on additional building materials, such as the M4 salt concrete, Sorelbeton A1, IM-ASSE 1 or Styromag ETO-I are planned or under discussion. The building material salt concrete has already been well investigated and, in analogy to conventional, salt-free building materials, contains gel, capillary and air pores, which will be filled to a large extent with pore solution at the time of a potential solution influx. The currently developed MgO building material MO1 has hardly been investigated so far. Since this was developed on the basis of Sorelbeton A1, it is assumed that the MgO building material has similar properties to Sorelbeton A1. Further information on the composition of the construction materials can be found in /2/ and /2/ (salt concrete) and /3/ (magnesia construction material). The necessary determination of the hydraulic parameters of the above-mentioned building materials, including the bond with the rock mass and related questions, is to be covered by this performance specification.

Opportunity closing date

26 September 2022

Value of contract

to be confirmed