Rippability assessment of weathered granite rock mass using seismic velocity and graphical method

Abstract

Seismic refraction methods and Electrical Resistivity Tomography (ERT) are commonly used as geophysical methods for rock mass characterization and ground subsurface for excavation assessment. In this study, this method was used in the BJ Kota Tinggi Quarry, Johor to evaluate the characteristics of granite and geological features and perspective zones for excavatability. There are two (2) seismic and two (2) electric resistivity surveys were performed at this site with 69m and 80m respectively. The seismic data were processed using SeisOptPicker and SeisOpt2D software. Resistivity data were interpreted and analyzed by using the software RES2DINV. Materials with seismic velocities greater than 2000 m/s show no ripping. While a low resistivity value is obtained due to fracture zones found in harder rocks that have been filled by water or clay minerals. This seismic velocity profile is then compared with the Rippability Chart by Caterpillar using the smallest ripper D8R, to obtain the rippability of the rock. While the evaluation of excavatability is carried out using the graphical method Pettifer and Fookes (1994), consider discontinuity spacing and point load index (IS(50)). The results show that the research that can be carried out is ripping, more economical and suitable for use at this site.