Effect of hydraulic conductivity and impeded drainage on the liquefaction potential of gravelly soils
Effect of hydraulic conductivity and impeded drainage on the liquefaction potential of gravelly soils
复制标题
导水率和排水障碍对砾石土液化潜力的影响
DOI：
10.1139/cgj-2021-0579
复制
发表时间：
2022
影响因子：
3.6
通讯作者：
Rollins, Kyle M.
中科院分区：
文献类型：
--
作者：
Roy, Jashod;Rollins, Kyle M.
研究砂和细粒含量以及原位排水条件在控制砾石沉积物水力传导性中的作用，对于表征砾石土壤的液化潜力非常重要。在本研究中，根据现有的砾石液化案例历史，经验得出了水力导电性随含砂量的变化。研究发现，含砂量超过20%-30%的土基质的水力导率低到足以引起液化，而不存在任何不透水的围水层。此外，利用商业软件FEQDrain进行了数值研究，研究了在各种地震荷载作用下，在不同相对密度和水力导率下，有和没有不透水帽层的砾石土中孔隙压力的产生。无论在无侧限还是侧限条件下，超孔隙压力比都随着水导率(k)和相对密度（Dr）的降低而增加。超孔隙压力比与水导率、土壤压缩性和循环应力比（CSR）相关。在密闭条件下，砾石层孔隙压力主要受上覆盖层控制，即使是砂质盖层而不是高度不透水的粘土层也会引起液化。
Investigating the role of sand and fines content and in situ drainage conditions in governing the hydraulic conductivity of gravelly deposits is highly important to characterize the liquefaction potential of gravelly soil. In this study, a variation of hydraulic conductivity with sand content has been empirically obtained based on the existing gravel liquefaction case histories. It is found that the hydraulic conductivity of a soil matrix having more than about 20%–30% sand content by mass is low enough to cause liquefaction without the presence of any impervious confining layer. In addition, a numerical study has been performed using the commercial software FEQDrain to study pore pressure generation in gravelly soil at a variety of relative densities and hydraulic conductivities with and without an impermeable cap layer when subjected to a variety of earthquake loadings. For both unconfined and confined condition, excess pore pressure ratios consistently increase with a decrease in hydraulic conductivity (k) and relative density (Dr). Excess pore pressure ratio is correlated with hydraulic conductivity, soil compressibility, and cyclic stress ratio (CSR). For the confined condition, pore pressure in the gravel layer is primarily governed by the overlying cap layer and even a sandy cap layer instead of highly impervious clay layer can cause liquefaction.