| Abstrakt: |
This study investigates the reliability of subgrade soil materials along the Dawanau-Kazaure railway line by analyzing compaction characteristics, including California bearing ratio (CBR), Maximum dry density (MDD), and Optimum moisture content (OMC) derived from field and laboratory data. Statistical information for basic random variables was generated using Minitab 15 software, and limit-state equations were formulated for each compaction characteristic. These limit-state equations are based on regression equations developed from field and laboratory data. The safety of the subgrade material was assessed across a range of coefficient of variation values (from 10% to 100%). The findings revealed that as the coefficient of variation increased, reliability indices generally decreased. For all cases considered, the reliability indices obtained for bearing capacity failure were positive, indicating the subgrade material's overall safety, but did not meet the minimum recommended value of 1.0 set by the Nordic Committee on Building Regulations. Therefore, the subgrade soil requires improvements in its index properties. Specifically, the expected values of the California Bearing Ratio for soaked and unsoaked soil samples were 32.5% and 78%, respectively, with corresponding reliability indices of 0.9275 for soaked CBR and 0.9250 for unsoaked CBR. [ABSTRACT FROM AUTHOR] |
