Correlation of sandstone rock properties obtained from field and laboratory tests

The unconfined compressive strength of rocks plays an important role in many practices for geotechnical engineering. It is used to determine the bearing capacity of soil specially rocks. The real value of this parameter requires a special technique such as undisturbed samples. So, prediction of unconfined compressive strength of sandstone rocks with the help of rock quality designation (RQD) provides a good opportunity to obtain this parameter without using of more laboratory tests. The RQD is commonly used for rock description or classification, and ….etc. Correlation of properties obtained from field and laboratory tests is considered the most important challenge for geotechnical engineers to save time, effort and many tests. This study was undertaken in order to quantify the variation of the values of unconfined compressive strength due to variation of (RQD). Many field boreholes have been investigated for this purpose. Unconfined compressive strength tests were conducted using samples of different values of RQD. This paper proposed a new empirical equation to predict the unconfined compressive strength for sandstone rock.