深部煤矿巷道围岩软弱、裂隙发育，动载影响下易引发动力灾害，其中软岩及节理岩体动力学试验研究是解决上述问题的关键。3D打印技术因其能突破浇筑法在制作复杂节理试样上的局限，被广泛应用于岩石力学试验研究，而应用该技术的关键是所制类煤试样的静态和动态力学特性与天然岩石相似。本文基于砂型3D打印试样，通过开展单轴压缩、巴西劈裂等力学试验，揭示了砂型3D打印试样与煤样弹塑性力学特性的相似性，利用分离式霍普金森压杆（SHPB）装置开展不同动静组合加载试验，采用宏观破碎块度和细观电镜扫描综合分析等手段，对不同动静组合荷载下砂型3D打印试样的动力响应与破坏特征进行研究。结果表明：砂型3D打印试样的动态强度和组合强度与冲击气压的增大呈正相关关系，动态强度与轴压的增大呈负相关关系，组合强度随轴压的增大呈先增大后减小的变化，这说明岩石抵抗动载的能力随轴压的增大呈先增强后减弱的变化；随着静、动荷载水平的提高，试样的破碎块度逐渐细粒化，其中动载对试样破碎程度的影响最显著。本文揭示了砂型3D打印试样的动力学特性并验证了其应用于煤岩动力学试验的可行性，为采用砂型3D打印技术开展岩石动力学试验提供了重要基础，研究结果有助于进一步揭示不同地应力与动载条件下围岩动力破坏规律。

The surrounding rocks of deep coal mine roadway are weak and fractured,and some dynamic disasters are easily induced by external dynamic loads. Therefore,dynamic test with soft rock and jointed rock mass is an important basis to solve the above problems. The 3D printing technology can overcome the limitations of the casting method in making complex joint rock-like specimens,thus it is widely used in experimental research in the field of rock mechanics,and the key to its application is the similarity between the 3D printing specimens and natural rocks in static and dynamic mechanical properties. With sand-powder 3D printing specimens,the similarity of elastic-plastic properties between the sand-powder 3D printing and coal specimens was revealed by carrying out conventional mechanical tests,such as uniaxial compression and Brazilian tests. The split Hopkinson pressure bar(SHPB)device was used to carry out different coupled static and dynamic loads tests. The dynamic response and failure characteristics of specimens were studied by means of macroscopic fragmentation and mesoscopic scanning electron microscope. The results show that the dynamic strength and combined strength are positively correlated with the increase of impact pressure,and the dynamic strength is negatively correlated with the increase of axial pressure. The combined strength increases first and then decreases with the increase of the axial pressure,which shows that the dynamic-resistant ability of the specimens increases first and then decreases with the increase of axial pressure. With the increase of static and dynamic loads,the fragmentation of the specimens is gradually fine-grained,and the dynamic load has the most notable influence on the fragmentation of the specimen. This paper reveals the dynamic characteristics of the sand-powder 3D printing specimens and verifies the feasibility of its application in the dynamic tests with coal and soft rocks,and hereby provides an important basis for rock dynamics tests using the sand-powder 3D printing technology. The research results contribute to further investigations on the dynamic failure characteristics of surrounding rock under different in-situ stress and dynamic load conditions.

1 砂型3D打印试样制备与试验设计

   1.1 3D打印技术在岩体力学领域应用现状

   1.2 3D打印试样制备

   1.3 动静组合试验设计

2 动静组合作用下试样动力学特性

   2.1 应力-应变曲线特征

   2.2 不同动静荷载对强度特性的影响规律

3 动静组合作用下试样破坏特征

   3.1 试样破碎块度分布规律

   3.2 试样微观破坏模式与形貌细观分析

4 讨论

5 结论