Shear behavior of a two-component non-water reactive foamed polyurethane (TNFPU) grouting material under different stress levels

Abstract

The two-component non-water reactive foamed polyurethane (TNFPU) material utilized in structural restoration scenarios may experience shear failure when subjected to multifaceted external factors, potentially culminating in structural instability or even failure. Consequently, it is imperative to conduct a thorough examination of the shear properties of TNFPU material. A series of direct shear tests were conducted to investigate the impact of factors such as density, normal stress, and shear rate on the shear properties of TNFPU material. These properties encompass shear strength, shear modulus, peak shear displacement, shear deformation, and shear dilation angle. The findings underscore the density and normal stress had more significant effects on the shear properties of TNFPU material. Conversely, the impact of shear rate on shear performance was relatively modest and exhibited a diminishing trend as density increased. Notably, a specific discovery emerged: the effects of density, normal stress, and shear rate on the shear properties of TNFPU displayed pronounced distinctions before and after reaching a critical density threshold of 0.51 g/cm³ . Furthermore, the study revealed a phenomenon of shear dilation and contraction transformation when the density or normal stress exceeded a certain critical value.