【作者】 韩华强；

【导师】 陈生水；

【作者基本信息】 南京水利科学研究院 ， 岩土工程， 2003， 硕士

【摘要】 本文利用常规直剪仪、三轴仪以及轻便固结仪，分别对非饱和膨胀土的强度和变形特性以及干湿循环对强度和变形的影响进行了一系列的试验研究。以饱和度、干湿循环次数为变量，分别探求了外力约束对膨胀土强度的影响，不同饱和度膨胀土的总应力强度特性，干湿循环对非饱和膨胀土总应力强度的影响，饱和度与压缩模量以及孔隙比的关系，干湿循环对饱和膨胀土有效应力强度指标的影响，广义吸力与饱和度的关系，建议了一组计算非饱和膨胀土变形及强度特性的经验公式。 在试验的基础上结合广义吸力提出了非饱和膨胀土预应力的概念，认为预应力强度的存在是非饱和膨胀土与饱和膨胀土的主要差别。 最后我们采用两个算例分别计算了干湿循环对非饱和膨胀土路基沉降以及边坡稳定的影响，通过计算得出了在以非饱和膨胀土作为构筑物基础或构筑物时，应认真考虑干湿循环对其强度和变形特性降低的影响的结论。更多还原

【Abstract】 In this paper, the influence of cycles of drying and wetting on strength and deformation are studied by means of routine direct shear apparatus , triaxial apparatus and light consolidation apparatus which include: the influence of force of constraint on strength, the total stress strength of expansive soils with different saturation degree, the influence of cycles of drying and wetting on the total stress strength, the relation between saturation degree and compression modulus and that between saturation degree and void ratio, the influence of cycles of drying and wetting on the effective stress strength, the relation between saturation degree and generalized suction. As a result, a group of experience equations of strength and deformation of expansive soils are suggested.Moreover, the concept of prestress of unsaturated expansive soils is given in this paper, it is found that the prestress strength is the main difference between unsaturated expansive soils and saturated expansive soils.Finally, two examples were used to analyse the influence of cycles of drying and wetting on subgrade sedimentation and slope stability of expansive soils, the conclusion is given that the influence of cycles of drying and wetting on strength and deformation must be considered to the foundation or structures which consists of expansive soils.更多还原