Development of 3D rapid prototyping system for large-scale physical modeling of complex rock masses and engineering structures with case study analysis

Similar physical model tests in geotechnical engineering encounter significant challenges, particularly in accurately representing complex stratigraphic structures, engineering geometries, and structural plane morphologies. Conventional industrial 3D printing techniques often fail to meet the specific requirements of geotechnical modeling. To address this gap, we have developed a three-dimensional rapid prototyping system designed for fabricating large-scale similitude physical models of complex rock masses and engineering structures. This system employs a dual-nozzle pumping extrusion molding method and incorporates technological innovations in several key areas, including the pumping system, extrusion system, and dual-nozzle switching system. These advancements effectively resolve critical issues such as the extrusion of high-viscosity printing materials, material overflow during dual-nozzle switching, and frequent clogs during extended printing sessions. Functional tests demonstrate that the equipment can rapidly fabricate physical models of complex rock masses and engineering structures using multiple materials, exhibiting high forming precision, excellent printing compactness, fast printing speeds, straightforward disassembly, and ease of cleaning. Subsequently, the device was utilized to produce rock-like specimens containing weak interlayers and tunnel physical models with interlayer structures. Case study analyses confirm that the system effectively meets the demands of physical model testing in geotechnical engineering, providing valuable technical support for innovations in rock mechanics theory and the safe construction of infrastructure engineering projects.