加筋粗粒土筋土界面剪切特性与统计损伤软化模型研究
Shear behavior of geogrid-soil interface and its statistical damage softening model

土工合成材料与土的界面力学特性对于加筋土结构设计与稳定性分析具有重要意义。采用大型直剪试验研究不同法向应力下粗粒土与土工格栅界面的剪切特性。试验结果表明：筋土界面剪切应力与剪切位移曲线呈现出应变软化特征，加筋粗粒土较素粗粒土界面黏聚力增加，但内摩擦角降低；格栅的加筋作用明显减小了加筋粗粒土在峰值后强度的降低幅度，提高了土体的延性。基于统计损伤理论提出了考虑筋土界面应变软化特性的统计损伤本构模型，通过与试验结果进行对比分析，该模型能较好地反映筋土界面的应变软化特征，验证了模型的合理性。
The interface mechanical properties between geosynthetics and soil are of great significance for the design and stability analysis of reinforced soil structure. In this study, large direct shear tests were performed on coarse-grained soil with/without geogrid reinforcement under different normal stress. The test results show that interface shear stress-shear displacement curves are characterized as strain softening; Compared with the no-reinforced case, the case reinforced with geogrid have larger cohesion and lower friction angles. The reduction in shear strength after reaching max value is obviously diminished and the ductility of soil is enhanced due to geogrid reinforcement. Based on statistical damage theory, a new statistical damage constitutive model is proposed to describe the strain-softening characteristics of geogrid-soil interface. Furthermore, the proposed model is verified by experimental results