Evaluation of dynamic properties of calcareous sands in Egypt at small and medium shear strain ranges
Evaluation of dynamic properties of calcareous sands in Egypt at small and medium shear strain ranges
复制标题
DOI：
10.1016/j.soildyn.2018.09.030
复制
发表时间：
2019
影响因子：
4
通讯作者：
A. Morsy;M. Salem;H. Elmamlouk
中科院分区：
文献类型：
--
作者：
A. Morsy;M. Salem;H. Elmamlouk
钙质砂矿广泛分布在埃及地中海沿岸，被称为北海岸地区，涵盖了工业和旅游活动的前景广阔的地区。采用无固定共振柱仪对北海岸两个地区采集的砂土在中、小剪应变范围内的剪切模量值和阻尼比进行了试验研究。此外，还估计了弯曲和约束模数、弯曲阻尼比和泊松比。研究了有效围压、空隙比和饱和条件(饱和与干燥)对评估的动态特性的影响。最大剪切模数随有效围压的增加呈指数增加，与已报道的硅质砂相比，其指数值相对较高。孔隙率对剪切模量值的影响在孔隙率较低时更为明显，最大剪切模量值随孔隙率的减小而增大。与饱和砂岩相比，颗粒不规则、粗糙的干胶结砂具有较低的最大剪切模数和较高的应力指数。天然胶结作用改变了砂粒间的性质，从而间接影响了砂土的动力性质。
Calcareous sand deposits are widely distributed along the shoreline of Mediterranean Sea in Egypt; known as the North Coast area, which covers promising areas for industrial and touristic activities. An experimental study was conducted to evaluate the shear modulus and damping ratio at small and medium shear strain ranges of sands procured from two districts along the North Coast using fixed-free resonant column apparatus. In addition, flexural and constrained moduli, flexural damping ratio, and Poisson's ratio were estimated. Effects of effective confining stress, void ratio, and saturation condition (saturated versus dry) on evaluated dynamic properties were investigated. The maximum shear modulus increased with increasing the effective confining stress exponentially with relatively high exponent values compared to those reported for siliceous sands. The effect of void ratio on shear modulus was more pronounced at low void ratios and maximum shear modulus increased as the void ratio decreased. Dry cemented sands characterized with their irregular and rough particles showed lower maximum shear moduli and higher stress exponents compared to saturated sands. Natural cementation was found to indirectly influence the dynamic properties of sands as it alters the inter-particle properties.