The influence of a grain-shape fabric on the mechanical behaviour of rock salt: Results from deformation experiments
The influence of a grain-shape fabric on the mechanical behaviour of rock salt: Results from deformation experiments
复制标题
DOI：
10.1016/j.tecto.2018.12.009
复制
发表时间：
2019-01
期刊：
影响因子：
2.9
通讯作者：
J. Linckens;G. Zulauf;M. Mertineit
中科院分区：
文献类型：
--
作者：
J. Linckens;G. Zulauf;M. Mertineit
为了研究岩盐颗粒形状择优取向对岩盐变形的影响，进行了平面应变实验。来自北方德国Asse矿的天然石盐立方体，在345 °C、大气压和~10−7s−1的应变速率下变形，其中有SPO和没有SPO。SPO与主缩短方向Z成不同角度（θ = 0°、45°和90°）。样品被限制在Y方向上，并且可以自由地移动到主拉伸方向X。大部分应变由位错蠕变提供。应力-应变数据的定性分析显示了SPO对力学数据的明显影响。在一个缩短应变约。-10%，β = 0°和45°的样品比没有SPO的样品弱。相比之下，具有β = 90°的样品比没有SPO的样品更强。在所有样品中形成新的SPO，其粒形组构的长轴近似平行于主拉伸轴X。在这些较大的缩短应变下，样品显示出相似的强度，除了90°取向的样品仍然比没有SPO的样品更强。尽管必须改进实验装置以获得关于SPO对岩盐机械强度的影响的定量结果，但结果表明，岩盐的SPO可能在建造核废物处置库时必须考虑，并且可能对洞穴的稳定性产生影响。
In order to assess the effect of shape preferred orientation (SPO) of halite grains on deformation of rock salt, ductile plane strain deformation experiments have been conducted. Natural halite cubes with and without an SPO from the Asse mine of northern Germany were deformed at 345 °C, atmospheric pressure and a strain rate of ~10−7s−1. The SPO was oriented at different angles (ß = 0°, 45° and 90°) to the main shortening direction,Z. The sample is confined in theYdirection and can freely move to the principal stretching direction,X. Most of the strain was accommodated by dislocation creep. The qualitative analysis of the stress-strain data shows the clear influence of the SPO on the mechanical data. At a shortening strain of ca. −10%, the samples with β = 0° and 45° are weaker than the samples without an SPO. In contrast, the sample with β = 90° is stronger than the samples without an SPO. A new SPO is formed in all samples with the long axis of the grain shape fabric being subparallel to the principal stretching axis,X. At these larger shortening strains, the samples show similar strength, with an exception of the 90° oriented sample that is still stronger than the samples without an SPO. Even though the experimental set up has to be improved to obtain quantitative results on the influence of SPO on mechanical strength of rock salt, the results show that the SPO of rock salt likely has to be taken into account when building a repository for nuclear waste and could have an effect on the stability of caverns.