Study on uniaxial compression mechanical properties of 3D printed columnar joint test blocks

Area of Science:

• Materials Science
• Geomechanics
• Civil Engineering

Background:

• Columnar joint rock masses (CJRM) are common geological formations.
• Understanding their mechanical behavior is crucial for engineering applications.
• 3D printing offers novel ways to create controlled experimental models.

Purpose of the Study:

• To investigate the mechanical properties and failure modes of CJRM test blocks incorporating 3D printed Acrylonitrile Butadiene Styrene (ABS) skeletons.
• To analyze the influence of joint skeleton dip angle and ultraviolet (UV) aging on CJRM behavior.
• To evaluate the effect of ABS material degradation on the overall performance of the test blocks.

Main Methods:

• Columnar joint rock mass (CJRM) test blocks were fabricated using 3D printed ABS skeletons, cement mortar, and subjected to UV aging.
• Uniaxial compression tests were performed on specimens with varying dip angles.
• Analysis included strength, deformation, energy absorption, and failure modes.
• The impact of UV aging on ABS properties was assessed through yellowness index and infrared spectroscopy.

Main Results:

• CJRM exhibited high anisotropy; uniaxial compressive strength and elastic modulus showed a 'U'-shaped trend with dip angle, while elastic strain energy showed a 'V'-shaped trend, with minimums at 45°.
• Observed failure modes included shear, splitting, and mixed types.
• The ABS skeleton reduced the strength and elastic modulus of the solid test block, with the most significant reduction at a 75° dip angle.
• Increased UV aging time led to decreased ABS strength and deformation parameters, alongside increased yellowness and infrared spectral peak area, indicating material degradation.

Conclusions:

• The presence of an Acrylonitrile Butadiene Styrene (ABS) skeleton significantly influences the mechanical properties and failure mechanisms of columnar joint rock mass (CJRM) models.
• The dip angle of the joint skeleton is a critical factor determining CJRM strength and deformation characteristics.
• Ultraviolet aging degrades ABS material, negatively impacting the mechanical performance of CJRM test blocks, highlighting the need to consider material durability in design.