结构性砂土胶结厚度分布特性试验研究

Experimental and Numerical Research on Bonding Properties of Structured Sand

颗粒间胶结物厚度对胶结颗粒接触力学特性有显著影响,进而影响结构性砂土离散元模拟结果。为更好地模拟天然砂土的结构性,需要明晰结构性砂土中颗粒间胶结厚度分布特性,并且能在离散元模拟中反映该分布特性。本文采用人工制备结构性砂土,开展电镜扫描试验,对结构性砂土中颗粒间胶结厚度分布特性进行了研究。研究结果表明:在结构性砂土中,随着水泥含量的增加,平均胶结厚度近似线性增加;但是水泥含量对胶结厚度的概率分布规律影响不大,水泥含量不同的结构性砂土,其颗粒间胶结厚度概率分布均为先线性增大,后指数型衰减。在试验研究结果的基础上,提出了离散元模拟结构性砂土胶结厚度的方法,可以较好地反映结构性砂土中颗粒间胶结厚度指数型衰减的分布特性。

The bonding thickness plays an important role in the mechanical behaviors of the inter-particle bonding,and then significantly influences the simulations of structured sands using DEM. So it’s necessary to get a better understanding of the distribution of inter-particle bonding thickness and take it into account in the DEM simulations. The distribution of inter-particle bonding thickness is experimentally studied by performing SEM on the artificially structured sands. The results show that the average bonding thickness increases almost linearly with the increasing cement content. However,the cement content only slightly influences the probability distribution of inter-particle bonding thickness. There is an exponential decrease in the probability distribution after its initial linear increase with bonding thickness. A method simulating the bonding thickness in DEM,which can capture the exponential decrease of the probability distribution of bonding thickness,is proposed based on the experimental results.