高温作用后3D打印岩体试样力学性能初探

实际岩土工程中经常遇到高温环境,研究3D打印岩体试样在高温作用后的力学性能对促进3D打印技术在工程领域的应用具有重要意义。以GS19砂和呋喃树脂作为打印基材,运用3D打印技术制备内部结构高度一致的岩体试样,研究不同温度作用后3D打印岩体试样的力学性能,结合电镜扫描试验从微观层面上分析不同温度作用后3D打印岩体试样力学性能产生变化的原因。提出了3D打印岩体试样的最优力学温度,并研究了含预制裂隙的3D打印岩体试样在最优力学温度作用后的破坏特征。研究表明:3D打印岩体试样的单轴抗压强度与劈裂抗拉强度随温度的不断升高均呈现先增大后降低的规律,最优力学温度为150℃;在最优力学温度作用后,含不同倾角预制裂隙的3D打印岩体试样的破坏过程包含压密、微裂纹萌生、裂纹稳定扩展、贯通破坏4个阶段,裂纹的初始萌生位置均出现在预制裂隙处但随着预制裂隙倾角的变化而有所不同,扩展路径总是趋向于荷载加载的方向并大致呈中心对称形式。

Mechanical properties of 3D printed rock samples subjected to high temperature treatment

Geotechnical engineering often encounters high temperature environment. It is important to study the mechanical properties of rock samples printed in 3D subjected to high temperature treatment to promote the application of 3D printing technology in engineering field. Using GS19 sand and furan resin as printing substrates, rock samples with highly consistent internal structure were prepared by 3D printing technology and the mechanical properties of rock samples printed in 3D subjected to different temperature treatments were studied. The reasons for the change in mechanical properties of rock samples printed in 3D at different temperatures were analyzed from the microscopic level by scanning electron microscopy. The optimal temperature of 3D printed rock samples are proposed and the failure characteristics of 3D printing rock samples with prefabricated cracks after optical mechanical temperature action are studied. The uniaxial compressive strength and splitting tensile strength of 3D printed rock samples increase first and then decrease with increasing temperature. The optical mechanical temperature is 150 ℃. After the optical mechanical temperature effect, the failure process of 3D printed rock samples with different inclined cracks includes four stages, i.e. compaction, micro-crack initiation, stable crack propagation and penetration failure. The initial crack initiation locations appear at the prefabricated cracks, but with the change in inclination of prefabricated cracks, the propagation path always tends to the direction of load loading and is approximately centrosymmetrical.