The core-disk phenomenon has been observed generally in the drilling process under high-stress conditions. This paper presents the in-situ experimental study of the coring-disking failure mechanism of marble in an underground cavens with 2400 m depth. Based on the disk samples in several boreholes with different diameters, both macro- and micro-morphological characteristics of core-disks’ break surface were analysis, using 3D optical scanning and electron microscope scanning. Moreover, the numerical back analysis was also used to simulate the drilling process for demonstrating the development of core disking. The in-situ experiment results showed that the failure types of core disking consisted of tensile break and shear break, i.e., the shear break usually appears in the edge part of break surface, and tensile break appears in the central part. What’s more, the ration of core-disks thickness to borehole diameter is in a relatively stable range. Numerical back analysis indicated this micro asynchronous break of hard marble is induced by high geostress and unloading drill.

通常在高应力条件下的钻孔过程中观察到芯盘现象。本文对2400 m深度地下洞室中大理石的取芯-破坏机理进行了现场试验研究。基于几个直径不同的钻孔中的圆盘样品，使用3D光学扫描和电子显微镜扫描分析了核心圆盘断裂面的宏观和微观形态特征。此外，数值反分析也被用来模拟钻探过程，以证明岩心盘的发展。现场实验结果表明，岩心盘的破坏类型包括拉伸断裂和剪切断裂，即剪切断裂通常出现在断裂面的边缘部分，而拉伸断裂出现在中心部位。而且，岩心盘厚度与井眼直径之比在相对稳定的范围内。数值反分析表明，硬大理石的这种微小异步断裂是由高地应力和卸荷钻头引起的。