Abstract
Three-dimensional (3D) printing technology integrating frozen stress techniques has created a novel way to directly represent and characterize 3D interior discontinuities and the full-field stress induced by mining- or construction-related disturbances of deeply buried rock masses. However, concerns have been raised about the similitude between the mechanical behaviours of the printed model and its prototype rock mass. Ensuring the mechanical properties of the printable materials are as close as possible to those of real rock mass is of critical significance. In this work, a transparent, light, photosensitive polymer material was investigated for applications in frozen stress tests. The chemical composition of the material was determined by integrating the results of infrared spectroscopy (IR spectroscopy), X-ray diffraction (XRD), pyrolysis, gas chromatography and mass spectrometry (PY-GC/MS). Measures to improve the mechanical properties of the printable material, including printing orientation, post-processing, and temperature control, were evaluated by comparing the treated material with its prototype rock. The optical stress sensitivity of the material, including stress-visualized properties and stress-frozen performance, was also tested. This study offers an understanding of how printable materials should be modified to better simulate real rock masses, in terms of not only their geological geometry but also their mechanical performance.
Highlights
Mining and construction activities on deeply buried rock masses may induce large deformations in the surrounding rocks and disturbances in the geo-stress field, resulting in serious geological hazards[1,2,3,4]
To ensure that the physical and mechanical response of deep rock masses can be accurately reflected by 3D-printed geological models, improving the similitude between the physical and mechanical behaviours of the printed model and real underground rock is of critical significance
Due to the different sedimentary and forming processes of natural reservoir rocks, their interior structure and physical and mechanical properties vary widely, which leads to great difficulties in developing 3D printing materials that are transparent, optical stress sensitive and that possess the same or similar mechanical properties as those of natural rocks
Summary
Mining and construction activities on deeply buried rock masses may induce large deformations in the surrounding rocks and disturbances in the geo-stress field, resulting in serious geological hazards[1,2,3,4]. The invisible and intangible nature and complex structure of rock matrices and diverse geological bodies make it extremely difficult to directly display the complex stratum structure and physically extract the stress field. A certain mismatch exists between the printed model and its prototype rock mass This mismatch is related to the mechanical and deformation performance due to the intrinsic nature of these materials. Few published results have investigated the impact of post-heat treatment on the mechanical properties of 3D printing materials solidified by UV light curing. The main objectives of this research are to introduce a transparent, photoelastic printable material, to study and modify its physical and mechanical properties, and to improve the similarity between its strength and stiffness and those of natural rocks. This study aims to provide a way to uncover the intrinsic governing mechanisms of engineering-related geological disasters
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