Geomechanical Evaluation of Lumle Rock (Pahara) Using Schmidt Hammer Rebound Testing for Assessing Rock Climbing Suitability

The surface hardness and estimated compressive strength of Lumle Rock (Pahara), situated in the Annapurna Rural Municipality of Kaski District, Nepal, were investigated using the Schmidt hammer (rebound hammer) test, a standardized non-destructive testing (NDT) method. This technique was employed to evaluate the geomechanical properties of the rock formation with specific attention to its potential for recreational rock climbing and site-specific geotechnical applications. Rebound values were collected in situ and statistically analyzed to determine characteristic strength at confidence intervals of 80%, 90%, and 95%, following the guidelines of IS 13311-Part 2. Critical factors influencing rebound measurements, including aggregate mineralogy, surface texture, moisture content, carbonation effects, and weathering conditions, were systematically considered and controlled where applicable. The results indicated that Lumle Rock (Pahara) exhibits sufficient surface hardness and mechanical integrity to support rock climbing activities. However, to ensure climber safety and to inform potential engineering uses, it is recommended that further subsurface investigations, including calibration, be conducted. The application of Schmidt Hammer testing in this context demonstrates the value of rapid, cost-effective assessment methods for evaluating the mechanical suitability of natural rock formations for recreational and civil engineering purposes.