Injections serve to improve the soil as well as to consolidate and seal the building ground. Consolidation injections are used to underpin buildings and as a securing method in pipeline and tunnel construction. Sealing injections are used to make construction pits watertight (closure of gaps and sealing of tunnel floor) and curtain sealing for barrages, weirs and dams.
During this process a liquid injection agent is injected into the existing cavities (pores in loose soil or fissures in rock) at low pressure. The cavity is built either by drilling or pile driving, depending on the geological conditions. Alternatively, the injection is carried out by means of drill pipes, injection lances or sleeve pipes. The injection agent can also be injected into the ground on a chemical or hydraulic basis. The limits of this process are dictated by the fineness of grain of the soil and the respective size of the pore. Should it no longer be possible to inject the agent into the pore space, the jet grouting method can be used instead.
Metro Station Heinrich-Heine-Allee in Dusseldorf is located underneath the Kaufhof building at Königsallee. Compensation injections secured the listed building during construction of the new metro line Wehrhahnlinie.