In order to overcome the disadvantage of traditional joint fabrication method—inability to reproduce the rough surfaces of practical rock joints—3D-printing technology was applied to restructure five kinds of rough joint according to the failure surface formed by the triaxial prepeak unloading test in this study. And uniaxial compression test was carried out on the rock-like specimens containing closed 3D-printing rough joint to study the effects of joint inclination and joint length on the mechanical properties (peak strength, peak strain, elastic modulus, and secant modulus), cracking process, and failure modes. Besides, digital image correlation (DIC) method and acoustic emission (AE) system are used to investigate the whole evolution process of strain fields and crack propagation during loading. It is found that the mechanical parameters decrease first and then go up as the joint inclination increases, while presenting a continuous downward trend with the increase of joint length. Inclination of 45° and the larger joint length bring more extensive reduction to mechanical properties of specimens. Specimens exhibit typical brittle failure characteristics. The failure mode of specimens affected by different joint inclination is tension-shear failure. And the joint scale rises; the failure mode of specimens changes from tensile failure to shear failure. Larger joint scale results in the longer prepeak fluctuation phase on axial stress-strain curves and more dispersed distribution of high-value AE counts.

中文翻译：

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基于3D打印技术的含闭合粗糙节理状岩石试样断裂演化过程的实验研究

为了克服传统节理制作方法的缺点，即不能再现实际岩石节理的粗糙面，根据三轴预峰卸载试验形成的破坏面，采用3D打印技术对五种粗糙节理进行了重构。研究。然后对包含闭合3D打印粗糙接缝的岩石样试样进行单轴压缩试验，以研究接缝倾角和接缝长度对机械性能（峰值强度，峰值应变，弹性模量和割线模量），开裂的影响。过程和故障模式。此外，利用数字图像相关（DIC）方法和声发射（AE）系统来研究加载过程中应变场和裂纹扩展的整个过程。研究发现，随着关节倾角的增大，力学参数先减小，然后增大，而随着关节长度的增加，力学参数呈现连续下降的趋势。45°的倾斜度和较大的接点长度会更广泛地降低样品的机械性能。标本表现出典型的脆性破坏特性。受不同关节倾角影响的试样的破坏方式为拉伸剪切破坏。并且联合规模上升；试样的破坏方式从拉伸破坏变为剪切破坏。较大的接头比例会导致轴向应力-应变曲线上的前峰波动阶段更长，并且高价值AE计数的分布更加分散。45°的倾斜度和较大的接点长度会更广泛地降低样品的机械性能。标本表现出典型的脆性破坏特性。受不同关节倾角影响的试样的破坏方式为拉伸剪切破坏。并且联合规模上升；试样的破坏方式从拉伸破坏变为剪切破坏。较大的接头比例会导致轴向应力-应变曲线上的前峰波动阶段更长，并且高价值AE计数的分布更加分散。45°的倾斜度和较大的接头长度使试样的机械性能更加广泛地降低。标本表现出典型的脆性破坏特性。受不同关节倾角影响的试样的破坏方式为拉伸剪切破坏。联合规模上升；试样的破坏模式从拉伸破坏变为剪切破坏。较大的接头比例会导致轴向应力-应变曲线上的前峰波动阶段更长，并且高价值AE计数的分布更加分散。试样的破坏方式从拉伸破坏变为剪切破坏。较大的接头比例会导致轴向应力-应变曲线上的前峰波动阶段更长，并且高价值AE计数的分布更加分散。试样的破坏模式从拉伸破坏变为剪切破坏。较大的接头比例会导致轴向应力-应变曲线上的前峰波动阶段更长，并且高价值AE计数的分布更加分散。