# Development of an Automatic Rock Mass Classification System Using Digital Tunnel Face Mapping
## 3 Automated Rock Quality Classification Using Digital Tunnel Face Mapping
### Automated Rock Mass Classification System  
The construction field manager is a key player in reporting tunnel face mapping and rock mass quality rating results to stakeholders, including clients and upper management. This process is significantly optimised by utilising the developed software system, which facilitates effective communication and data management. During the digital mapping of each tunnel section, geological information and quantitative data are systematically stored in a digital format on a dedicated server. Utilising an automatic rock quality evaluation program, the stored digital information is aligned with parameter grades contained in RMR or Q-value rating sheets, thereby enabling the automatic computation of the final rock mass quality score. The software automatically calculates geometric information, such as the average spacing and length of joints, using computational formulas. The strike and dip directions are also displayed as numerical data and subsequently stored in the database for future reference. This integration of geometric data enhances the precision of the rock mass evaluations. The average roughness of joint surfaces visible on the excavation face is classified into five distinct categories, ranging from'very rough' to'slickenside'. This classification is visually represented using varying line thicknesses corresponding to each joint set, providing a clear indication of joint characteristics. The composition and thickness of fill material within the joints are denoted by colours: black indicates no fill material, red indicates hard fill material with a thickness greater than 5 mm, orange denotes hard fill material of 5 mm thickness or less, purple signifies soft fill material exceeding 5 mm, and green represents soft fill material with a thickness of 5 mm or less. The weathering of the wall rock adjacent to the joints is represented by different line types. For instance, a double solid line signifies unweathered wall rock, a solid line indicates slight weathering, a single dashed line represents moderate weathering, a double dashed line indicates high weathering, and a dotted line signifies completely weathered rock. Groundwater characteristics at the excavation face are quantified by translating the observed outflow into measurable values that are stored in the database. This quantitative representation aids in the assessment of rock mass parameters for subsequent evaluations. Figure 11: Reference window for selecting the groundwater condition. The orientation of the major joint is recorded numerically during mapping by assessing the angle between the tunnel excavation direction and the major joint. These orientation data serve as a reference for automated rock mass evaluations, contributing to the accuracy of the calculations. The resultant correction value is integrated into the final rock mass rating. Figure 12 delineates the procedure for deriving the ultimate rating value by correlating the geometric and physical characteristic values generated during the tunnel digital mapping process with the RMR or Q-value classification tables. Figure 12: Rating parameters by matching the digital mapping to the RMR value table. (**a**) Rating R1 (rock strength) and R2 (drill core quality) parameters. (**b**) Ratings R3 (joint spacing), R4-1 (joint length), and R4-2 (joint aperture). (**c**) Ratings R4-3 (joint roughness), R4-4 (joint filling), and R4-5 (joint alteration). (**d**) Rating R5 (groundwater condition).