284 As shown in Figure 4, the entire scanning system consists of three parts: scanning software, a controller, and a stage. The stage can accommodate test specimens with a height below 75 mm and a weight less than 4.5 kg. The horizontal travel range of the X-Y axes is 184 × 88 mm, while the vertical travel range of the Z-axis is 73 mm. During the scanning process, the specimen is first placed on the stage, and autofocus is used to lock the scanning height before initiating the scan. During scanning, two telecentric lenses mounted on the top of the stage emit white LED beams, which are reflected off the object's surface and then captured by another telecentric lens equipped with a 1-inch, 4-megapixel monochrome CMOS sensor to form an image. Finally, the software resolves the 3D contour scanning results of the object's surface with a display resolution of 0.1 μm. 2.3 Experimental Materials The basic physical and mechanical parameters of the bluestone sandstone samples used in the experiments are presented in Table 1. Table 1 - Physical and mechanical parameters of experimental rock specimens Rock Type Density (kg/m3) Void Ratio (1) Elastic Modulus (GPa) Internal Friction Angle (°) Cohesion (MPa) Compressive Strength (MPa) Tensile Strength (MPa) Green Sandstone 2355.03 0.1464 16.52 46.54 9.75 65.35 4.85 2.4 Experimental Arrangement The experimental arrangement is shown in Table 2. Table 2 - Test design of spherical and conical double-inserted teeth penetration rock No. Stress Environment Insert Type Penetration Velocity / mm·min-1 Penetration Depth /mm 1 axial pressure 20 MPa confining pressure 20 MPa spherical-spherical dual inserts conical-conical dual inserts 0.6 2.5 2 4.0 3 0.9 2.5 4 4.0 5 1.2 2.5 6 4.0 7 1.5 2.5 8 4.0 9 1.8 2.5 10 4.0 As shown in Table 2, a total of 30 sets of experiments were conducted, in which bluestone sandstone was penetrated by spherical-spherical and conical-conical dual inserts at different penetration velocities and depths, with an insert spacing of 10 mm (i.e., twice the insert diameter). The study aimed to investigate the relationship between the rock-breaking
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