Utilization of the point load index method as an estimator of rock compressive strength in civil engineering

Lawa Cave is one of the geotourism sites located in Purbalingga, Central Java, specifically on the eastern slope of Mount Slamet. The large number of tourists visiting each year and the construction of several buildings inside the cave necessitate an assessment of how strong Lawa Cave is in terms of its load-bearing capacity. This study aims to analyze the compressive strength of the rock and provide recommendations on the safety level of the cave in withstanding the load from building structures and visitors. In this study, field observations and primary data collection were conducted, involving the collection of rock samples from several points within the cave. These rock samples were then analyzed at the Rock Mechanics Laboratory of the Mining Engineering Program at Institut Teknologi Nasional Yogyakarta. Rock compressive strength testing was conducted using the Point Load Index testing method. Conversion of the Point Load Index test results to rock compressive strength values was 11.21 MPa until 37.57 MPa. This value indicates that the Lawa Cave rock mass has adequate bearing capacity for structural buildings, suitable as a support layer for light to medium structures with recommended reinforcement such as rock bolts, wire mesh, and shotcrete.