Mechanics performance and failure modes of fracture grouting reinforced body in water-rich soft surrounding rock
The mechanics performance and failure modes of fracture grouting reinforced bodies in water-rich soft surrounding rock have a significant impact on the grouting effectiveness.A grouting simulation test was conducted to investigate the morphological and spatial distribution characteristics of grout veins and the reinforcement mechanism of grouting.Triaxial compression tests were performed on grouting reinforced body specimens,and corresponding discrete element numerical simulations were carried out.The effects of grout veins roughness,thickness,quantity and dip angle on the mechanical performance and failure modes of grouting reinforced body specimens were analyzed.The evolution of internal porosity and microcracks under triaxial loading conditions was also examined.The results indicate that there are three distinct spatial distribution patterns of grout veins,namely semi-through,cross and through types.The areas affected by grouting are classified as reinforcement,transition,and undisturbed regions.The stiffness and bearing capacity of the grouting reinforced body are improved due to the presence of grout veins,with the peak deviator stress of specimens positively correlated with the roughness,thickness and quantity of the grout veins.However,the strength of the specimens decreases with the increase of the dip angle of grout veins.The failure modes of grouting reinforced body specimens include the local expansion and shear slip types,and their contributions to the deformation are differentially affected by the morphological characteristic of grout veins.The microcracks are first initiated at the soil-slurry vein interface,and then numerous microcracks appear at the weak rocks around grout veins due to the compressed and compacted action under loading process.The porosity variation and initiation of microcracks in the grouting reinforced body are significantly influenced by the morphological characteristics of the grout veins,exhibiting distinct stage of evolution.
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