Evaluation Of Rock Abrasiveness Based On A Digital Drilling Test

The accurate evaluation of rock abrasiveness is the basis for the cutting tool design of tunnel boring machines and efficient tunneling. However, the conventional test method is complicated and costly, and in situ measurement cannot be obtained easily. A new digital drilling test system was developed to assess rock abrasiveness in which drilling parameters, including the thrust on bit, rotational speed, torque, and drilling displacement, can be simultaneously collected. Based on the force analysis of the drill bit and the energy conservation law, the energy dissipation per unit volume of drilling or modified specific energy was proposed as an evaluation index, and the quantitative relationship between the index and rock abrasiveness was explored and verified. The results showed that the average difference rate between the Cerchar abrasiveness indexes obtained from the digital drilling test and Cerchar test was less than 15 %, thus proving the effectiveness and feasibility of this method for evaluating rock abrasiveness. The method is easy to implement and has few requirements for sample preparation. It can also be used for the in situ testing of rock abrasiveness in engineering sites.