ABSTRACT
The necessity of grouting for the purpose of sealing is mainly derived from the result of water pressure tests. A grouting zone for sealing purposes shall form a complete unit with the structure or with its sealing element. The purpose of a reasonable borehole arrangement is to achieve a coherent grouting zone. For grout curtains the boreholes are arranged in one or more rows parallel to each other. Borehole spacing within the rows and row spacing depend on the effective radius of grouting. Consolidation grouting serves to consolidate the rock in the foundation, i.e. to increase the bearing capacity and to exclude further settlements under the dam load. In contrast, contact grouting serves to create tight connection of structures to the foundation, capable of distributing stresses without deformation. Such contact grouting is required around galleries and other embedded structures. It is not required in the contact area of a sealing element.
