Epoxy injection is a structural repair, not a waterproofing technique, used to re-establish the integrity of a cracked beam or column, haunch or etc.
Specially designed injection ports are inserted into holes drilled into the existing crack. Epoxy is then injected into the holes from a hose. The hose is then moved up to the next port when the epoxy reaches it from the previous one. This process is continued along the full length of the crack.