Abstract

This paper highlights the effect of non-plastic fines on sand matrix by performing a series of undrained triaxial tests. The silty sand specimens were reclaimed by moist tamping method and two distinct density indexes of sand matrix were selected: I_Dmat=0.00 (<0.15) for very loose state and I_Dmat=0.50 (>0.40) for medium-dense state. The addition of non-plastic fines to the host sand matrix makes the specimens more resistant to liquefaction by inducing dilatant behaviour and reducing the excess pore water pressure Δu. As for instability line in the very loose state (I_Dmat=0.00), a rotation is observed on the p^’-q plane with increasing non-plastic fines fraction. This trend is non-linear and becomes less remarkable after a certain threshold value in fines fractions. In the medium-dense state (I_Dmat=0.50), there is no significant effect of non-plastic silt particles on the phase transformation state. Regarding the ultimate steady state, the line is unified in the p’-q space, but a clockwise rotation is observed in the log(p’)-e space. Furthermore, the exponential form shows a good fitting performance for silty sand.

摘要

本文通过进行一系列不排水三轴试验，强调了非塑性细粒对砂基质的影响。粉砂试样采用湿捣法进行再生，并选择了两种不同的砂基质密度指标：非常松散状态的 I _Dmat =0.00（<0.15）和中等致密状态的I _{Dmat =0.50（>0.40）。}在主砂基质中添加非塑性细粒通过诱导膨胀行为和降低超孔隙水压力 Δu 使试样更耐液化。至于非常松散状态下的不稳定线（I _{Dmat =0.00），在 p} ^'上观察到一个旋转-q 平面，非塑性细粒分数增加。这种趋势是非线性的，并且在细粒分数达到某个阈值后变得不那么显着。在中等致密状态（I _Dmat =0.50），非塑性粉砂颗粒对相变状态没有显着影响。关于最终稳态，这条线在 p'-q 空间中是统一的，但在 log(p')-e 空间中观察到顺时针旋转。此外，指数形式对粉砂具有良好的拟合性能。