Small-strain shear modulus (Gmax) and microscopic pore structure of calcareous sand with different grain size distributions

IF 2.3 3区工程技术 Q3 MATERIALS SCIENCE, MULTIDISCIPLINARY Granular Matter Pub Date : 2022-09-12 DOI:10.1007/s10035-022-01270-2

Shao-Heng He, Meisam Goudarzy, Zhi Ding, Yifei Sun, Tao Xu, Qiong-Fang Zhang

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引用次数: 2

Abstract

The maximum shear modulus (G_max) is a key material characteristic that is incorporated in advanced soil constitutive models. Numerous experimental studies have been conducted to describe the effects of particle sizes and packing characteristics on G_max. However, most of these studies were conducted on quartz-based sands. A review of the literature revealed that few studies have described the effects of grain size distribution (GSD) on G_max in calcareous sands. Therefore, bender element (BE) tests were performed on calcareous sands with different mean grain sizes (d₅₀), uniformity coefficients (C_u), and void ratios to obtain G_max. The BE results revealed that the G_max of calcareous sand increases slightly with increasing d₅₀ but decreases significantly with increasing C_u. A modified model of G_max incorporating the effects C_u and d₅₀ was therefore developed for calcareous sand. Moreover, microscopic observations of pore size distributions (PSD) obtained from nuclear magnetic resonance (NMR) tests were presented to demonstrate the effect of GSD on PSD and its correlation with G_max. The NMR results revealed that the interaggregate pore structure proportion and uniformity of the PSD decreased significantly with increasing C_u but increased slightly with increasing d₅₀. The underlying mechanism for the effect of GSD on G_max was related to its substantial impact on microstructure. The significant decrease in G_max with increasing C_u can be attributed to the remarkable reduction in the ratio of the interaggregate void ratio to the intraaggregate void ratio. Additionally, G_max was enhanced as the heterogeneity of the microporosity structure distribution decreased.

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不同粒径分布钙质砂的小应变剪切模量(Gmax)与微观孔隙结构

最大剪切模量(Gmax)是先进土本构模型中包含的关键材料特性。已经进行了大量的实验研究来描述颗粒大小和堆积特性对Gmax的影响。然而，这些研究大多是在石英砂上进行的。通过对文献的梳理发现，钙质砂中粒径分布对Gmax影响的研究很少。为此，对不同平均粒径(d50)、均匀性系数(Cu)和孔隙比的钙质砂进行弯曲单元(BE)试验，获得Gmax。BE结果表明，随着d50的增加，钙质砂的Gmax略有增加，但随着Cu的增加，Gmax显著降低。因此，建立了考虑Cu和d50效应的钙质砂Gmax修正模型。此外，通过核磁共振(NMR)测试获得了孔隙尺寸分布(PSD)的微观观察结果，以证明GSD对PSD的影响及其与Gmax的相关性。核磁共振结果表明，随着Cu的增加，PSD的团间孔隙结构比例和均匀性显著降低，但随着d50的增加，PSD的团间孔隙结构比例和均匀性略有增加。GSD对Gmax影响的潜在机制与其对微观结构的实质性影响有关。Gmax随Cu的增加而显著降低，其原因是集胞间空隙比与集胞内空隙比的比值显著降低。Gmax随微孔结构分布不均一性的减小而增大。图形抽象

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来源期刊

Granular Matter Materials Science-General Materials Science

CiteScore

4.60

自引率

8.30%

发文量

审稿时长

6 months

期刊介绍： Although many phenomena observed in granular materials are still not yet fully understood, important contributions have been made to further our understanding using modern tools from statistical mechanics, micro-mechanics, and computational science. These modern tools apply to disordered systems, phase transitions, instabilities or intermittent behavior and the performance of discrete particle simulations. >> Until now, however, many of these results were only to be found scattered throughout the literature. Physicists are often unaware of the theories and results published by engineers or other fields - and vice versa. The journal Granular Matter thus serves as an interdisciplinary platform of communication among researchers of various disciplines who are involved in the basic research on granular media. It helps to establish a common language and gather articles under one single roof that up to now have been spread over many journals in a variety of fields. Notwithstanding, highly applied or technical work is beyond the scope of this journal.