摘要
针对原状非饱和及饱和黄土的体积变形问题,提出了一个复合体计算模型。该模型将黄土看作由各自均匀分布于土中的原状部分和扰动部分组成的,这两部分土体的体积比率,可由黄土结构的微观几何模型、孔隙率密度曲线及考虑广义吸力的微结构失稳条件计算得出。假设原状部分仅发生弹性变形,扰动部分符合重塑土的变形规律。复合体的应变增量包括原状部分的弹性、重塑土的塑性及结构崩塌3部分;其中:结构崩塌变形特指微结构失稳时原状土体的孔隙率突然变为重塑土的孔隙率;重塑土的体积应变形采用广义吸力理论计算。采用不同的初始饱和度的黄土结构强度计算出非饱和土微观结构刚度与饱和度的函数,从而获得非饱和土黄土微观结构失稳的判别条件。分别计算了低含水天然非饱和及饱和黄土的压缩曲线,并与试验结果对比说明了模型的合理性。
A new compound model is developed to calculate volumetric strains of unsaturated and saturated collapsible loess. In this model, loess is regarded as the compound of undisturbed and disturbed parts, both of which are respectively and uniformly distributed in loess; and the proportion of the two parts can be calculated through the combination of a pore size distribution curve; a suggested geometric structural model and structural instability criterion with the generalized suction being considered. The volumetric strain increment includes three components： the elastic increment of undisturbed part; the plastic increment of disturbed part determined by the application of the generalized suction theory; and the structure collapse contribution which is particularly relevant to the change of void ratio from undisturbed soils to disturbed soils. The relationship between the angle-stiffness of the structural instability criterion and the degree of saturation is determined by the structural strengths revealed by compression tests of natural loess. The rationality of this model is verified by comparing calculated results with published experimental data.
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2007年第12期2517-2523,共7页
Rock and Soil Mechanics
基金
甘肃省自然科学基金(No.GZS041-A25-041)
关键词
湿陷
微结构
失稳
黄土
collapse
microstructure
instability
loess
