Fully automatic large-scale rock shearing machine in a cold chamber

在全球范围内，高山岩石面的永久冻土退化导致落石、岩石雪崩和大型山体滑坡的急剧增加。我们在2013年提出了一个全面的岩石-冰力学模型，其中包括（i）岩石力学，（ii）冰力学和（iii）岩石-冰界面的力学变化。为了对（i）不同岩性、（ii）不同压力和温度条件、（iii）全球相关变形机制和速度的岩石-冰力学模型进行参数化，我们需要能够全面模拟（i）-（iii）的剪切装置。我们已经发表了超过40篇关于岩石冻结行为的现场和实验室初步试验的文章，通常使用自行修改的实验室设备，是该领域的国际领先研究小组。对于岩石冰力学模型的普遍适用性，我们需要（i）大型冷剪切试验系统，（ii）可自由缩放的变形和载荷，（iii）依赖于连续性的长期蠕变试验的能力（iv）循环温度变化和同步测量（v）关键地球物理参数。此次采购活动的中心目标是一台全自动岩石剪切试验机，用于确定岩石、岩石/冰试样以及其他与边坡运动有重要关系的自然发生的主要是冻结材料的剪切强度、蠕变特性和循环材料疲劳。此外，无侧限压缩试验和间接拉伸试验将是可能的。为了精确控制冷冻标本，有必要将仪器放置在具有热动态轨迹（低至约-20 ° C）的冷室中。由于尺度效应是相关的，因此应该可以测试高达300 x 300 x 200 mm的试样。100 kN以提高效率。500 kN的剪切力和1000 kN的法向力以及热条件对测试架的刚度和强度提出了特殊要求，以便能够在高达500（1000 kN）和2000 mm/min（100 kN）的剪切速率下测量0.01 mm范围内的平移。同时，还必须测量声发射、P波和S波，以及未来的自电位/电阻率。测试可能持续长达一个月，样品很难获得（高山，北极），需要高水平的过程可靠性，这是由所描述的机器保证的。

Globally, degrading permafrost in high alpine rock faces leads to a sharp increase in rockfall, rock avalanches, and also large landslides. We presented a comprehensive rock-ice mechanical model in 2013 that includes the (i) rock mechanical, (ii) ice mechanical, and (iii) mechanical changes at the rock-ice interface. To parameterize the rock-ice mechanical model for (i) different lithologies, (ii) different pressure and temperature conditions, (iii) relevant deformation mechanisms and velocities globally, we need a shear device that can comprehensively simulate (i)-(iii). We have published >40 articles with field and laboratory preliminary tests on rock freezing behavior, often with self-modified laboratory devices, and are a leading international research group in this field. For universal applicability of the rock ice mechanics model, we need a (i) large-scale cold shear test system, with (ii) freely scalable deformations and loads, (iii) the capability for trajectory-dependent long-term creep tests (iv) with cyclic temperature changes and simultaneous measurement of (v) key geophysical parameters. The central object of this procurement activity is a fully automated rock shear tester to determine shear strengths, creep properties, and cyclic material fatigue of rock, rock/ice specimens, and other naturally occurring, predominantly frozen materials that have significant relevance to slope movement. In addition, unconfined compression tests and indirect tensile tests will be possible. For accurate control of the frozen specimens, it is necessary to place the instrument in a cold chamber with thermal dynamic trajectories (down to about -20°C). Since scale effects are relevant, it should be possible to test specimens up to 300 x 300 x 200 mm. In addition, smaller specimens can be tested in a rock shear device in the cold chamber with max. 100 kN to increase efficiency. The shear force of 500 kN and normal force of 1000 kN and the thermal conditions place special demands on the rigidity and strength of the test frame in order to be able to measure translations in the 0.01 mm range, at shear rates of up to 500 (1000 kN) and 2000 mm/min (100 kN). At the same time, acoustic emission, P- & S-waves, and in the future also the electrical self-potential/resistivity, have to be measured. The tests, which can last up to one month, and the samples, which are difficult to obtain (high mountains, Arctic), require a high level of process reliability, which is guaranteed with the machine described.