饱和重塑黄土在部分排水条件下的力学特性研究

针对黄土地区实际加载工程中部分排水问题，利用多功能GDS应力路径三轴仪开展饱和黄土不同排水条件下的三轴试验，研究了不同排水条件下饱和重塑黄土的强度特性。试验结果表明：饱和重塑黄土的强度随应变增量比的增大而增大，剪切过程中产生的超孔隙水压力随应变增量比的增大而减小；不同排水条件对土的强度特性的影响在两个方面：一是荷载条件，即土的有效应力路径，使得排水和吸水条件的加载模式不同；二是土性条件，即体积变形约束制约着土样剪胀特性的发挥，进而影响内摩擦角的发挥程度，形成渐近状态。根据试验数据，分析了不同排水条件下应力路径及渐进状态变化规律，调整了极限应力比的计算方法，得出饱和重塑黄土的极限应力比与应变增量比的线性关系方程。

Mechanical properties of saturated remolded loess under partial drainage conditions

Aiming at the investigation of partial soil drainage under loading conditions of engineering projects in loess areas, we conduct triaxial tests of saturated loess samples using a muti-functional GDS stress path triaxial apparatus, and examine the strength of saturated remolded loess under different drainage conditions. Results show that as the strain increment ratio increases, the strength increases while the excess pore water pressure generated through shearing decreases. The influence of partial drainage on soil strength is in two aspects: one is that the load condition, or the effective stress path of soil, makes the loading mode of drainage different from that of water absorption; the other is the soil property, i.e., the volume deformation characteristics influence the development of shear dilatation and thereby affects the internal friction angle of soil so that finally the soil develops into an asymptotic state. Based on the present experimental data, we analyze the variation trends in stress path and asymptotic state under different drainage conditions, adjust the calculation method of limit stress ratios, and obtain a linear relationship equation of limit stress ratio versus strain increment ratio of saturated remolded loess.