摘要
基质吸力-饱和度的本构关系对研究非饱和土强度和变形具有重要意义。为考虑土体中存在的不同孔隙结构,以及孔隙比对毛细和吸附作用的不同影响,建立了一个单/双峰土体持水曲线(soil-water retention curve,简称SWRC)模型。明确区分了毛细和吸附作用的持水机制,将毛细饱和度和吸力的关系描述为与孔径分布特征有关的函数,而对吸附饱和度的模拟中显式地考虑了毛细凝聚的影响,并提出了毛细和吸附饱和度的解耦公式。此特性为合理地考虑SWRC对孔隙比的依赖关系奠定了基础,即孔隙比对SWRC的影响主要作用在毛细水部分,这也与微观试验揭示的规律一致。基于改进的模型提出了一种不同初始孔隙比下非饱和土强度的预测方法。利用不同类型土体的持水试验和强度试验数据验证了模型的有效性。
The constitutive relationship between suction and degree of saturation is of great significance for estimating the shear strength and deformation behavior of unsaturated soils. A unimodal/bimodal soil-water retention curves(SWRC) is proposed considering the effects of various pore structures and the effects of void ratio on capillarity and adsorption. The different mechanisms of water retention through capillarity and adsorption are explicitly distinguished in the proposed model. The relationship between the capillary degree of saturation and suction is described as a specific function related to the characteristics of pore-size distribution, while the adsorptive degree of saturation is modeled considering the effect of capillary condensation explicitly. Subsequently, the decoupling formula of capillary and adsorptive saturation is further put forward. The formula lays a foundation for the model to account for the dependence of capillary part of SWRC on void ratio, which is consistent with the results from micro-scale tests. Eventually, an approach to estimate the shear strength of unsaturated soils with different initial void ratios has been proposed based on the improved SWRC model. The model is verified using data from water retention and direct shear tests reported for various types of soils in the literature.
作者
林志强
钱建固
时振昊
LIN Zhi-qiang;QIAN Jian-gu;SHI Zhen-hao(Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 20092,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2021年第9期2499-2506,共8页
Rock and Soil Mechanics
基金
国家自然科学基金项目(No.41877252)。
关键词
土体持水曲线
单双峰
毛细作用
吸附作用
孔隙比
强度预测
soil-water retention curve
unimodality/bimodality
capillarity
adsorption
void ratio
strength
