Development and Application of a Multifunction True Triaxial Rock Drilling Test System

Abstract

The real-time acquisition of the rock mass mechanical parameters and the rapid classification of the surrounding rock during the construction of an underground structure are of great value for informational construction and optimization of the parameters of the supporting structure. However, it is currently difficult to rapidly acquire rock mass mechanical parameters at construction sites. The “digital drilling rig”–based drilling test technique is an effective approach for addressing this problem. Therefore, this study develops a multifunction true triaxial rock-drilling test system (TRD system). This system can be employed to test various types of rock or fractured rock masses to determine the correlations between the drilling parameters and the rock mechanical parameters under three-dimensional confining pressure conditions. This article introduces the basic features and the composition of each component of the TRD system. Drilling tests on different types of rock specimens under various control parameter conditions are performed, and the drilling tests on sandstone specimens under different confining pressures were carried out. The test results demonstrate significant correlations between the drilling parameters and between the drilling parameters and the rock mechanical parameters during the drilling process. The drilling parameters are responsive to confining pressure. The conclusions of the correlation analysis and the stable monitoring data obtained under various test parameter conditions verify the reasonableness and effectiveness of the TRD system’s structure. This study lays the foundation for further investigations of the quantitative relationships between the drilling parameters and the rock mechanical parameters and develops a key technology that uses the drilling parameters of a “digital drilling rig” to characterize the mechanical parameters of the surrounding rock at underground construction sites.