Abstract:
Stop Criteria form the basis for design and execution of grouting works in rock formations. Therefore, the type of stop criteria as well as the parameters are essential for the quality and success of grouting works. Based on these criteria, the appropriate improvement of the rock formation must be guaranteed (under varying ground conditions) and additionally, widening of fissures or jacking must be avoided. In many European Countries, stop criteria such as the GIN-Method (Grouting Intensity Number), TPAMethod (Transient Pressure Analysis), RTCG-Method (Real-Time-Grouting-Control) or PSG-Method (Pressure Sensitive Grouting) have been successfully used in many rock grouting projects. The European way of practice is slightly different to the approach used in the United States, where methods such as the Amenability Theory or ACG-Method (Aperture Controlled Grouting) are common. In this contribution, the different theories and practical applications will be discussed by an analysis of real-time grouting data recorded on an Alpine rock grouting project. By considering one single grouting operation, the results of different approaches in the respective theories will be shown. The contribution will express which conclusions can be derived about the conditions in the fracture system and which statements can be made just from a simple consideration of the grouting pressure and flow rate over time. The results and conclusions obtained from this analysis, assessed regarding their application limits, as well as advantages and disadvantages will be illustrated in the presentation. New insights for the use of the various methods in practice will be discussed. Additionally, we will point out briefly a current research project in Austria and Germany about possibilities of artificial intelligence for the assessment of rock grouting. The aim of the contribution is to close the gap between theory and practice with respect to stop criteria in rock grouting and to demonstrate new approaches for designers and contractors.