Relationships between compression wave velocity and unconfined compression strength for weathered Florida limestone

It is widely known that weathering has a negative effect on the physical and engineering properties of rock. The variably weathered near surface limestone bedrock in Florida presents a challenge to geotechnical engineers who must incorporate physical and engineering properties in their design. Twenty-two specimens of Ocala limestone were obtained from a geotechnical test site in central Florida. Weathering was assessed in the specimens by using the International Society of Rock Mechanics (ISRM) weathering scale and surface textures. Unit weights, compression wave velocities from free-free resonant column (FFRC) tests and unconfined compression tests were performed on the specimens. Weathering was then incorporated into the relationship between unconfined compressive strength (UCS) and compression wave velocity. Results showed the specimens with the lowest ISRM weathering state had the highest correlation between UCS and compression wave velocity, specimens with high unit weights had well defined positive trends between UCS and compression wave velocity, and specimens with pitted and pitted to vuggy surface textures had strong positive relationships between UCS and compression wave velocity. Furthermore, it was found that other variables aside from the limestone weathering state influence the relationship between UCS and compression wave velocity.