3D打印技术在岩石物理力学试验中的应用

3D打印技术在岩土工程领域的应用还处于初步探索阶段,但其可重复制造含复杂内部结构的试样是常规室内试验无法实现的。现阶段制约3D打印技术在岩石物理力学试验中应用的主要因素在于3D打印试样强度偏低,延性较强。初步探讨了3D打印后干燥时间、打印胶水浓度对试样强度的影响,在此基础上提出了最优化打印方案,使打印试样在强度和脆性方面均有很大提升;通过改变打印方向模拟了天然层状节理岩石的各向异性特征。研究结果表明,随着打印倾斜角度的增加,3D打印试样的单轴抗压强度先减小后增大,呈"U"型变化趋势,抗拉强度也随打印方向的改变出现明显的各向异性特征,这与天然层状节理岩石相关研究成果相似。研究成果可为3D打印技术在岩土工程领域的推广和室内试验研究提供参考。

Application of 3D printing technology in physical modelling in rock mechanics

Although the application of 3D printing technology in physical modelling in rock mechanics is still at the preliminary stage of exploration, its reproducible production of specimens with complex internal structures is impossible for the conventional test method. At present, 3D printing technology is difficult to be applied in physical modelling in rock mechanics. The reasons are caused by the low strength of 3D specimens that is even lower than the weakest existing rock and the strong ductile behaviour of the 3D printed specimens. The main objectives of this study are to explore the effects of the drying time after printing and binder saturation level on the strength of the 3D printing specimens during UCS tests and Brazil disk split tests. Based on the test results, the study puts forward a set of optimum printing parameters, which can greatly enhance the strength of 3D printing specimens and reduce their ductile behaviour in the test. By changing the inclined angles of the printing layers, the specimens can be used to simulate the anisotropy of natural bedding joint rock. The results show that as the inclined angles increases, the uniaxial compressive strength of the 3D printing specimens decrease first and then increase, showing a U-shape trend. Besides, the tensile strength shows an obvious anisotropy with changing the printing directions. The results are similar to the previous results of natural bedding joint rock. The findings of this study verifies the feasibility of 3D printing technology in the experimental study on rock mechanics.