| Rock mass classification systems (Rock Mass Rating, RMR; Slope Mass Rating, SMR; and Rock Mass Strength, RMS) were applied at sites along road PR-139 in Ponce, a city located in the south of Puerto Rico in order to assess their "total rating" as indicators of rock mass conditions and stable slope angles of existing rock cuts. Adjustments were made to each system, weighted average adjustments for the discontinuities and weighted average adjustments including wedges that affect the stability, obtained from stereonets analyses; to determine which adjustment best estimates stable slope angles. The analyses indicate that where conditions for wedge failure are present the RMS with weighted average adjustments with wedges gives better results and can be used to determine long-term stable slope angles. The SMR is more difficult to apply and is better to use with average adjustments. When condition for wedge failure is present, it does not give good results. The RMR is simple to apply, but require adjustments in the joint orientation ratings to intermediate class values. The RMR and RMS can be used together with design procedures to estimate slope angles and rock mass properties. |
