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有研究结果表明,孔隙比是影响土–水特征曲线(SWCC)的直接因素,而应力状态是通过孔隙比影响SWCC的间接因素。然而相关文献中关于孔隙比对SWCC影响的试验研究,一般只控制了试样的初始孔隙比相同或者不同,而在SWCC试验过程中对试样的孔隙比并没有加以控制。为了深化对孔隙比和应力状态对SWCC影响的认识,以山东东营黏土为研究对象,采用应力相关土水特征曲线仪,对试样沿预定路径进行单向压缩或单向压缩–回弹以后,控制竖向应力或孔隙比在脱—吸湿SWCC试验过程中保持不变。结果表明:在本次吸力范围内(未超过400 k Pa)的脱湿—吸湿过程中,即使竖向应力相同(等应力状态),只要孔隙比不同,则SWCC就不同;但只要保持试验过程中试样孔隙比不变(等孔隙比状态),则竖向应力的变化对SWCC几乎没有影响。等孔隙比状态下,即使竖向应力不同,但试样的进气值相近,脱/吸湿速率也几乎保持一致;等应力状态下,进气值随着孔隙比的增大而减小,脱—吸湿SWCC的滞回度和滞回圈面积随孔隙比增加而增大。研究结果对于建立SWCC模型时,如何选取模型参数具有理论指导意义。
Some studies have shown that the void ratio is a direct factor affecting the soil-water characteristic curve (SWCC), while the stress state is an indirect factor that affects the SWCC through the porosity ratio. However, the relevant literature on the porosity ratio on SWCC experimental study, the general control of the sample only the same or different initial porosity ratio, while in the SWCC test the void ratio of the sample is not controlled. In order to deepen the understanding of the influence of void ratio and stress state on SWCC, taking Dongying clay as the research object and using stress-related soil-water characteristic curve instrument, after unidirectional compression or unidirectional compression- Control of vertical stress or void ratio remains unchanged during the de-hygroscopic SWCC test. The results show that SWCC is different when the void ratio is different, even in the same vertical stress (equal stress state) during the desorption-moisture absorption within this suction range (up to 400 kPa), but as long as the experimental process The void ratio in the sample is constant (equal porosity ratio state), then the vertical stress change has almost no effect on the SWCC. In the case of equal pore ratio, even if the vertical stress is different, the air intake values of the samples are similar and the dehumidification / absorption rates are almost the same. Under equal stress, the air inlet value decreases with the increase of void ratio. - Hysteresis and hysteresis area of hygroscopic SWCC increases with increasing void ratio. The result of the research is of theoretical significance for how to choose the model parameters when establishing the SWCC model.