Feasibility Investigation of 3D Printing Technology for Geotechnical Physical Models: Study of Tunnels

The 3D printing (3DP) technology to produce accurate tunnel physical models is tested to overcome difficulties in the traditional preparation methods of geotechnical physical models. Four kinds of tunnel models are prepared by 3D printers, with gypsum powder and PLA (polylactic acid) material used as the printing materials. Uniaxial compression experiments of the 3DP tunnel specimens show that the deformation and failure characteristics of the general tunnel model and single-fault tunnel model are similar to those of the artificial model. A comparative study also shows that the printed rockbolt and lining support structures significantly improve the bearing capacity of the tunnel, while faults significantly reduce the stability of the tunnel. These experimental results are similar to those of the artificial models, tunnel engineering case studies and numerical simulation results, demonstrating that 3DP technology can be applied to the experimental study of physical models of tunnels. Moreover, the digital speckle correlation method (DSCM) is adopted to expose the evolution of the displacement fields and the crack propagation of printed models that contain faults during loading. These digital results also support that 3DP physical specimens can be used to analyze the general and local stability of complicated faulted tunnels. The presented studies show that 3DP technology will considerably progress the development of rock/rock mass mechanics research with the further development in its technology and materials.