Using shotcrete as lining supports can effectively prevent tunnels from the rock burst of the surrounding rock, while rock-concrete interfaces play key roles in determining the supporting effect. In the present study, both experimental and numerical efforts are made to quantify the effect of joint roughness coefficient (i.e., JRC ranging from 4 to 20) and interface shape (i.e., wave, triangle and ladder-shape) on the dynamic splitting properties of rock-concrete composites. The results show that the dynamic tensile increase factor of the quasi rock-concrete interface increases with the increase of JRC, but the variation of interface shape has a minor effect over the stress rate ranges of 21.95 and 88.14 GPa/s. Specifically, the dynamic tensile strength and dissipated energy of the rock-concrete composites increase by up to 79.25 % and 42.59 %, respectively, with the increase of JRC from 4 to 20, as more concrete hydration products can fill the interface cavities and result in a better bonding effect. In addition, the numerical results reveal that the composite interface exhibits confined tension failure when exposed to dynamic splitting tension, and the enhanced confining effect at higher JRC increases the shear strength of the interface. Overall, the findings can give a basis for optimizing the interfacial characteristics between rock and shotcrete against rock burst.

中文翻译：

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界面特性对准岩-混复合层动态劈裂行为的影响：面向抗岩爆的弹性隧道支护


使用喷射混凝土作为衬砌支护可以有效防止隧道受到围岩的岩石冲击，而岩-混凝土界面在决定支护效果方面起着关键作用。在本研究中，进行了实验和数值工作，以量化节理粗糙度系数（即 JRC 范围从 4 到 20）和界面形状（即波浪形、三角形和梯形）对岩石-混凝土复合材料动态分裂性能的影响。结果表明：准岩-混凝土界面的动拉增加因子随JRC的增加而增大，但在21.95和88.14 GPa/s的应力速率范围内，界面形状的变化影响较小。具体而言，随着 JRC 从 4 增加到 20，岩石-混凝土复合材料的动态抗拉强度和耗散能分别增加了 79.25 % 和 42.59 %，因为更多的混凝土水化产物可以填充界面空腔并产生更好的粘合效果。此外，数值结果表明，复合材料界面在受到动态劈裂拉力作用时表现出约束拉破坏，在较高JRC下增强的约束效应提高了界面的剪切强度。总体而言，这些发现可以为优化岩石和喷射混凝土之间的界面特性以抵抗岩爆提供基础。