不同成样方式下含水率与非饱和膨胀土抗剪强度的关系

Relations between water content and shear strength of unsaturated expansive soils based on different sample-preparing method

为探讨不同成样方式下土体抗剪强度与含水率的关系,以膨胀土为研究对象,测定3种成样方式下试样含水率与抗剪强度的关系,并与前人研究结果作对比分析。结果表明,成样方式对抗剪强度影响显著。含水率较低时,饱和脱水试样抗剪强度高于静压和吸水试样;当含水率超过某一临界值时,静压试样抗剪强度较高。3种成样方式下,都存在黏聚力曲线随含水率增加而急剧降低段,且黏聚力急剧降低的含水率起始点不同。由于成样方式影响,含水率增加导致土的密实度降低和颗粒间隙增大的程度不同,加之吸力存在滞后性,在工程实践中应对土的形成过程加以考虑。

In order to explore the relations between shear strength and water content under different sampling methods,by studying the based on expansive soil,the relations between water content and shear strength under three kinds of sample-preparing methods were determined,and the experimental results were compared with the previous studies. The researches show that different sample-preparing methods have significant effects on the shear strength. As the water content was lower,the shear strength of saturated dehydrate samples was higher than that of static pressure samples and water absorbing samples. When the water content exceeded a certain critical value,the shear strength of the static pressure sample was higher. With the increase of water content,cohesive strength curves under different methods have a sharp decrease,and the initial water contents where cohesion rapidly decreased were different. Because of the influence of sample-preapring methods,the increases of water content showed different effects on the density reduction and the particle spacing. Coupled with the existence of hysteresis suction,the formation process of the soil should be paid attention to in engineering practice.