GEOCISA has extensive experience in grouting of this type, having carried out a large amount of grouting in dam foundations.
This type of grouting with cement-bentonite mixes in dam foundations is currently being replaced by a new system, the ground intensity number (GIN) method, designed by G. Lombardi, which has been pioneered in Spain by GEOCISA, following the creator’s directives. GEOCISA has developed instrumentation and software to control the GIN grouting process.
The two basic characteristics of the GIN method are as follows:
- The grouting mix must not contain bentonite; instead a stable cement grout mix should be used with a super plastifier to lower the viscosity of the mix, reduce the “cohesion” value and turn the grout mix into a Bingham fluid.
- To minimise the risk of hydraulic fracturing of the rock mass, as well as limiting the grouting pressures and volumes, the injection interval is limited by the hyperbole P•V=constant