A new rock-engineering index to assess jointed rock mass groutability

Abstract

This paper aims at presenting a rock mass groutability index (RGI) based on the rock engineering systems (RES). After defining the rock grouting mechanism and identifying the main effective factors, an interaction matrix is introduced to study the groutability of rock masses. As the interaction matrix codes are not unique numbers, interactive intensities are calculated for interaction matrix and a group decision-making method, fuzzy Delphi analytic hierarchy process, has been used to determine the total weights of interactive factors, which is the crucial stage in the RES technique. To rate effective parameters on rock grouting, the result of numerical simulation together with experimental and analytical studies are used as in literature. As a result, an index, RGI is presented to predict the groutability potential of rock masses. Seven geological units of Sarvak formation in Bakhtiary dam are used as a case study to rate them by using this index. For the purpose of evaluation, cross-correlations between the Rock Quality Designation (RQD) and Lugeon values with RGI were done and it was observed that with increasing RQD values, the RGI increases and with increasing Lugeon values, the RGI decreases linearly with good correlation coefficients.