In the current literature, the existence of lithophysae can cause a substantial change in the mechanical properties of tuff rock. However, since the shapes and distributions of the lithophysae are typically irregular and random, exploring the influence of lithophysae existence on the engineering behavior of lithophysae-rich tuff rock using the actual samples is very challenging. Besides, it is almost impossible to control the geometry of the lithophysae in the actual samples. Accordingly, in an attempt to explore the influence of void porosity and geometry on the mechanical behavior of tuff rocks, solid cubes as well as porous cubes with voids having different geometries were made of tuff-like material, Hydro-StoneTB®, and tested under uniaxial compression. The Hydro-StoneTB® was chosen because it resembled the tuff rocks in regards to strength and deformation under uniaxial stresses. The results showed that void geometry along with void porosity has a significant impact on the mechanical behavior of tuff-like lithophysal material. However, the mechanical behavior of the tuff-like lithophysal material mainly depends on the void porosity. The compressive strength values decreased with increased specimen void porosity. The strength/void porosity relationship is essentially exponential over the 6–20% void porosity range. The percent change in uniaxial compressive strength from the solid cube value is roughly 59, 72, and 82% at 6, 13, and 19.5% void porosity, respectively. Additionally, considering the smallest bridge distance could improve the description of the influences of the void geometry on the mechanical properties of the tuff -like lithophysal material. Furthermore, for the void porosity ranging from 6 to 20%, the crack patterns of the Hydro-StoneTB® porous cubes showed that the axial splittings (tension failures) are the dominant failure modes. However, based on the void alignments and bridge distances, shear failures can occur.

中文翻译：

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空隙存在对凝灰岩类岩浆材料力学行为的影响

在目前的文献中，岩藻的存在会引起凝灰岩力学性质的实质性变化。然而，由于岩泡的形状和分布通常是不规则和随机的，因此利用实际样品探索岩泡存在对富含岩泡的凝灰岩工程行为的影响是非常具有挑战性的。此外，在实际样品中几乎不可能控制岩泡的几何形状。因此，为了探索空隙孔隙率和几何形状对凝灰岩力学行为的影响，实心立方体以及具有不同几何形状空隙的多孔立方体由类凝灰岩材料 Hydro-StoneTB® 制成，并在以下条件下进行测试单轴压缩。选择 Hydro-StoneTB® 是因为它在单轴应力下的强度和变形方面类似于凝灰岩。结果表明，空隙几何形状和空隙孔隙度对凝灰岩状岩浆材料的力学行为有显着影响。然而，凝灰岩状岩体材料的力学行为主要取决于孔隙率。抗压强度值随着试样空隙孔隙率的增加而降低。强度/孔隙率的关系在 6-20% 的孔隙率范围内基本上呈指数关系。在 6%、13% 和 19.5% 的孔隙率下，单轴抗压强度相对于固体立方体值的百分比变化分别约为 59%、72% 和 82%。此外，考虑最小桥距可以改善对空隙几何形状对凝灰岩状岩体材料力学性能影响的描述。此外，对于 6% 到 20% 的孔隙率，Hydro-StoneTB® 多孔立方体的裂纹模式表明轴向劈裂（拉伸破坏）是主要的破坏模式。然而，根据空洞排列和桥梁距离，可能会发生剪切破坏。