循环荷载下纤维加筋土与结构界面切特性研究

目前对于纤维加筋土体与结构界面的循环弱化影响规律尚需进一步研究。为此,针对循环剪切荷载下加筋结构力学特性变化规律,使用自主研发的大尺度恒刚度界面剪切仪,开展了纤维加筋土与结构界面在循环荷载作用下的力学特性试验研究。研究发现,界面剪应力、法向应力与剪切位移关系曲线分别呈"滞回环"和"碟"状发展,随循环次数的增加衰减速率逐渐减小,且峰值均出现在最大位移处。应力路径曲线呈"蝴蝶环"状发展,加入砂的土样界面摩擦角偏大。此外,由于纤维对土颗粒的约束作用,加筋土体的循环弱化程度小于非加筋土体。通过研究循环荷载下纤维加筋土与结构界面剪切特性,揭示了循环荷载作用下界面受力变形的规律和机理,为实际工程的应用提供参考。

Study on shear characteristics of interface between fiber-reinforced soil and structure under cyclic load

At present，the law of the cyclic weakening effect at the interface between fiber-reinforced soil mass and structure is necessary to be further studied. Therefore，aiming at the changing law of the mechanical characteristics of the reinforced structure，an experimental study on the mechanical characteristics of the interface between fiber-reinforced soil and structure under cyclic load is carried out with an independently developed large-scale shear apparatus for the interface of constant normal stiffness. The study finds out that the relationship curves of the shear stress and the normal stress with the shearing displacement stress of the interface exhibit the hysteresis loop shaped and disc-shaped developments respectively，while the attenuation rates are gradually decreased along with the increase of the cyclic number，while the peak values occur at the location of the maximum displacement. The stress path curves exhibit the butterfly ring shaped developments and the interface friction angle of soil sample is a little bit larger. Moreover，due to the restraint effect of fiber on soil particles，the cyclic weakening degree of the reinforced soil mass is less than that of the unreinforced one. Through the study on the shear characteristics of the interface between fiber-reinforced soil and structure，both the law and the mechanism of the stress deformation of the interface under the effect of cyclic load are revealed，thus a reference is provided for the practical engineering application concerned.