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Influence of mineral dissolution on the mechanical behaviour of a granular assembly under complex stress states
International Journal of Rock Mechanics and Mining Sciences ( IF 7.2 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.ijrmms.2020.104546
C. Chen , L.M. Zhang , P. Shen

Abstract Rock and soil are natural assemblies of mineral grains. Dissolution of mineral compositions in a granular assembly can dramatically disturb and change the microstructure. Once the soil fabric and inter-particle contacts change, large deformations can develop and the shear strength can decrease. Currently there is a lack of understanding and experimental evidence of geomaterial behaviour subjected to mineral dissolution under realistic complex stress conditions. In this experimental study, extensive laboratory tests were conducted to investigate changes in the stress-strain relation, shear strength and critical state of a granular assembly after experiencing a substantial loss of particles by salt dissolution. During the salt dissolution process, a larger shear stress or confining pressure leads to a smaller increase of void ratio, a smaller positive state parameter, and a weaker strain-hardening behaviour. After the salt dissolution, the material grading becomes narrower, the grading state index decreases and the specific void ratio increases, leading to an upward shift of the critical state line. However, the increase of void ratio is more than the upward shift of the critical state line, thus the stress state changes from the dense side to the loose side, accompanied by a change of shearing behaviour from strain-softening to strain-hardening. Nevertheless, as the critical friction angle is dominated by the inter-particle contacts among coarse particles, with almost no change in the coarse content of the post-dissolution materials, only a slight decrease of 2.3° in the critical friction angle is found.

中文翻译:

矿物溶解对复杂应力状态下颗粒组合力学行为的影响

摘要 岩石和土壤是矿物颗粒的自然组合。矿物成分在粒状集合体中的溶解会显着扰乱和改变微观结构。一旦土壤结构和颗粒间接触发生变化,就会产生大的变形,剪切强度会降低。目前,对于在现实复杂应力条件下矿物溶解的地质材料行为缺乏理解和实验证据。在这项实验研究中,进行了广泛的实验室测试,以研究在经历盐溶解造成的大量颗粒损失后颗粒组件的应力-应变关系、剪切强度和临界状态的变化。在盐溶解过程中,较大的剪应力或围压导致孔隙比的增加较小,较小的正状态参数和较弱的应变硬化行为。盐溶解后,材料级配变窄,级配态指数降低,比孔隙率增大,导致临界态线向上移动。然而,孔隙率的增加大于临界状态线的向上移动,因此应力状态由致密侧向松散侧变化,并伴随剪切行为从应变软化向应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。盐溶解后,材料级配变窄,级配态指数降低,比孔隙率增大,导致临界态线向上移动。然而,孔隙率的增加大于临界状态线的向上移动,因此应力状态由致密侧向松散侧变化,并伴随剪切行为从应变软化向应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。盐溶解后,材料级配变窄,级配态指数降低,比孔隙率增大,导致临界态线向上移动。然而,孔隙率的增加大于临界状态线的向上移动,因此应力状态由致密侧向松散侧变化,并伴随剪切行为从应变软化向应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。导致临界状态线向上移动。然而,孔隙率的增加大于临界状态线的向上移动,因此应力状态由致密侧向松散侧变化,并伴随剪切行为从应变软化向应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触决定,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。导致临界状态线向上移动。然而,孔隙率的增加大于临界状态线的向上移动,因此应力状态由致密侧向松散侧变化,并伴随剪切行为从应变软化向应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。伴随着剪切行为从应变软化到应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。伴随着剪切行为从应变软化到应变硬化的变化。然而,由于临界摩擦角由粗颗粒之间的颗粒间接触主导,溶解后材料的粗颗粒含量几乎没有变化,因此临界摩擦角仅略有下降 2.3°。
更新日期:2020-12-01
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