Engineering geological modeling of building stones (case study: Mahallat, Hajiabad travertine)

In the current research, geological-geomechanical modeling of the Mahallat, Hajiabad Travertine was conducted using 90 boreholes with a total length of 663.35 meters, at a large scale. To achieve the goal, first, 2D geological-geomechanical strip-logs, 3D lithological strip-logs, 3D lithological model of all boreholes, 3D fence diagram of lithology variations for the boundary boreholes and isopach map of the mining deposit were drawn. Afterward, statistical studies of the Core Recovery (RC) and Rock Quality Designation (RQD) data of the boreholes were performed, as well as 3D model of the RC data, 3D statistical map and 3D model of the RQD data were generated.The results of the research show that the average thickness of the deposit (containing travertine and marly travertine) equals to 4.05 meters, and the remaining reserve within the boreholes boundary is estimated 5,868,439 tons, indicating a significant and worthwhile reserve. The average RC of the boreholes is 77.4%, reflecting a relatively high quality of drilling operation and the deposit content. Also, the average RQD in the boreholes is 69.3%, classifying the quality of the Hajiabad Travertine based on the engineering rock classification using the RQD criterion as "fair". Based on the 3D statistical map of RQD data, the highest RQD values belong to the boreholes in the southern half of the area. The 3D model of the RQD also indicates that, in general, the quality of the Hajiabad Travertine stones are better in zones eastern 6 (6E), western 6 (6W), and 14 compared to the other zones.