Analysis of Sensitivity to Parameters Affecting Hydraulic Conductivity Values in Fractured Media Tedy Agung Cahyadi, Faizal Agung Riyadi, Dymas Albert Nasrulah Arifaini, Thema Arrisaldi, Maulana Nafid Hakim
Universitas Pembangunan Nasional Veteran Yogyakarta
Abstract
Hydrogeological modeling requires identifications of groundwater characteristics, particularly the hydraulic conductivity (K) value. Typically, a rock layer is assumed to be homogeneous with a predetermined K value, although in reality, this value can vary. Fractured rocks exhibit a higher degree of heterogeneity and complexity compared to sedimentary rocks. Sensitivity analysis is needed to assess the significance of contributing parameters towards the K value. K estimation uses geotechnical data such as Rock Quality Designation (RQD), joint spacing, joint separation, and lithology type from borehole cores. Regression analysis, correlation, coefficient of determination, and Standard Error of Estimate (SEE) are performed on these four parameters. Results show that joint separation has a correlation coefficient of -0.73 and a determination coefficient of 0.53, indicating the greatest influence. The lithology permeability index has the least influence, with a correlation coefficient of 0.27 and a determination coefficient of 0.07.
