Abstract The mechanism of fracture propagation, interaction and coalescence inside rock masses is a highly concerned issue in geotechnical engineering. But as it is difficult to manufacture 3D internal pre-fractures and observe directly the failure evolution process inside real rocks or their opaque similar materials, most previous studies have been limited to 2D conditions. The experiment investigation on 3D rock failure is still in a preliminary stage. In this study, a resin material has been developed by extensive formula tries. It is absolutely transparent and the ratio of tension–compression strength (brittleness value) can be 1/6.6 at −10 to −15℃. It is much more brittle and rock-like than analogous materials used by former scholars. A set of preparation, casting mould, and post-processing technologies were established and specimen-making with multiple pre-fractures is enabled. In the designed scheme, specimens are made with two parallel internal fracture surfaces yet of four different stagger separations. Uniaxial tests were carried out and the stress–strain relationship is analysed. It is shown that the specimen has gone through four stages as the traditional rock test before failure. Many diverse forms of secondary fractures, such as wrapping wing crack, petaloid crack, and giant quasi-wrapping fracture surface, which were not found in 2D conditions have appeared and their evolutions were clearly seen in each stage.

中文翻译：

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一种建模树脂材料及其在岩石破坏研究中的应用：具有两个 3D 内部断裂面的样品

摘要 岩体内部裂缝扩展、相互作用和聚结机理是岩土工程中高度关注的问题。但由于很难制造 3D 内部预裂缝并直接观察真实岩石或其不透明类似材料内部的破坏演化过程，因此大多数先前的研究仅限于 2D 条件。3D岩石破坏实验研究尚处于初步阶段。在这项研究中，通过广泛的配方尝试开发了一种树脂材料。绝对透明，-10～-15℃的拉压比（脆性值）可达1/6.6。它比以前的学者使用的类似材料更脆，更像岩石。一套制备、铸造模具，建立了后处理技术，实现了多次预断裂的标本制作。在设计方案中，试样由两个平行的内部断裂面制成，但有四个不同的交错间距。进行了单轴试验并分析了应力-应变关系。结果表明，试件在破坏前经历了与传统岩石试验一样的四个阶段。出现了二维条件下未发现的多种形态的次生裂缝，如缠绕翼状裂纹、瓣状裂纹、巨型拟缠绕断裂面等，其演化过程在各个阶段都清晰可见。进行了单轴试验并分析了应力-应变关系。结果表明，试件在破坏前经历了与传统岩石试验一样的四个阶段。出现了二维条件下未发现的多种形态的次生裂缝，如缠绕翼状裂纹、瓣状裂纹、巨型拟缠绕断裂面等，其演化过程在各个阶段都清晰可见。进行了单轴试验并分析了应力-应变关系。结果表明，试件在破坏前经历了与传统岩石试验一样的四个阶段。出现了二维条件下未发现的多种形态的次生裂缝，如缠绕翼状裂纹、瓣状裂纹、巨型拟缠绕断裂面等，其演化过程在各个阶段都清晰可见。