3D打印技术在岩体物理模型力学试验研究中的应用研究与展望

Application and prospect of 3D printing technology to physical modeling in rock mechanics

含内部三维缺陷的试样和含复杂地质结构的物理模型制作一直是制约岩石力学试验发展的主要原因之一,鉴于3D打印(3D Printing,3DP)技术可以便捷地制作含复杂结构的三维实体,将3DP技术引入到岩体/岩石力学试验的研究中。以粉末性石膏为打印材料制作了含内部多孔洞结构和预制裂隙结构的模型试样,力学试验表明,这2种打印试样的变形特征、破坏特征、强度特征以及裂隙扩展过程与岩石类材料较为一致;利用粉末性石膏和PLA材料为打印材料,制作出了含单断层和含锚杆衬砌支护工程的隧道物理模型,试验证明了断层的存在降低了隧道的稳定性,而锚杆衬砌支护系统可以有效地提高洞室的承载能力,而且3DP隧道模型的变形破坏过程与其他岩石类材料的物理模型试验结果和工程现场观测现象较为一致。同时,将3D光学面扫描技术和3DP技术相结合建立一种含自然节理面模型的制作方法,试验测试表明该方法能够较好地复制出节理面的形貌特征,并且试样的剪切力学性质和破坏特征具有很好的稳定性和一致性。通过上述3DP试样的初步力学试验测试表明该技术在岩体力学试验研究中的可行性。最后,进一步了探讨和挖掘了3D打印技术在岩石力学和岩体工程研究中的应用潜力。

The production of rock/rock mass physical models with defects or complex geological structure has been one of the bottlenecks hindering the development of mechanical tests of rock. 3D printing（3DP） technology can create conveniently 3D entities with complex structures, which provides an unprecedented opportunity to break through this bottleneck. In this paper, the model samples with multiple holes and pre-existed cracks are prepared with the powder-gypsum as the printing material. The mechanical tests show that the two models are similar to those of rock materials in characteristics of deformation, failure and strength and in processes of crack extension. The physical models of tunnel with a single fault and the lining with bolts are made by powder gypsum and PLA material. The experimental results of these models show that the existence of faults reduced the stability of tunnels, the support system of bolts and lining improved effectively the bearing capacity of the Chamber and the 3DP tunnel model simulate nicely the failure process of the tunnel. Moreover, a new method that combines 3D optical scanning and 3DP to prepare models with natural joint surface is presented. The proposed method replicated well the morphological features of natural joints, and the shear properties and failure characteristics are stable and consistent. In conclusion, the preliminary mechanical tests above have proved the feasibility of 3DP technique in the experimental study of rock mechanics. In the final part of the article, the broad prospect of 3DP technology in rock engineering was discussed.