考虑加载速率效应的黏土损伤特性研究

Investigation of clay damage characteristics with effect of loading rates considered

对黏土的强度与变形特性的研究是深基坑及矿井建设的施工设计基础,揭示不同固结压力和加载速率对应的黏土强度与损伤特性有助于更好地服务于地下结构的施工设计。对不同固结压力的黏土试样进行不同加载速率的三轴试验,分析黏土的应力-应变曲线及两种因素(固结压力、加载速率)对黏土强度的影响规律;对破坏后试样CT扫描,获取的试样内部裂隙的损伤分布揭示了三轴压缩试样呈现腰鼓状的原因;在试验的基础上,假设黏土的强度服从Weibull分布,引入加载速率对强度参数的影响规律,得到了考虑加载速率效应的黏土损伤本构模型。

The study of the strength and deformation characteristics of clay is the foundation of construction design for deep foundation pits and mines.Revealing the strength and damage characteristics of clay corresponding to different consolidation pressures and loading rates can help better serve the construction design of underground structures.This research conducts triaxial tests on clay samples with different consolidation pressures and loading rates to analyze the stress-strain curve of clay and the influence of two factors(consolidation pressure and loading rate)on clay strength.The CT scan of the damaged sample reveals the distribution of internal cracks and the reason for the bulging appearance of the triaxial compression sample.Based on the experiment and assuming that the strength of clay follows a Weibull distribution,the influence of loading rate on strength parameters is introduced,and a clay damage constitutive model considering the effect of loading rate is obtained.