Effect of filling grouting material on mechanical properties and mechanism of rock-like samples with double-crack
Grouting is one of the main technologies for controlling the stability of fractured rock masses,and different grouting materials have significant differences in their reinforcement effects on fractured rock masses.In thisstudy,three grouting materials,sulfate-aluminate cement(SAC),ordinary Portland cement(OPC),andepoxy resin(EPR),were selected to fill pre-existing parallel double-cracks rock samples,and uniaxial compression tests、AE and SEM tests were conducted on these samples.The results showed that epoxy resin filling had the highest strength for the fissured samples,followed by OPC cement,and SAC cement had the lowest strength.The failure mode of the samples was significantly influenced by the filling material,with EPR-filled samples not being controlled by pre-existing cracks,while SAC and OPC-filled samples mainly exhibited a tensile-shear mixed failure caused by crack extension and breakthrough.Electron microscopy scans indicated that the differences were primarily due to the bonding characteristics between the different grout types and the rock.The interfaces of SAC and OPC filling were of the cover type,while EPR filling belonged to the fusion type.Based on these experimental results,a numerical model representing different bonding patterns was established using the Particle Flow Code(PFC),and the reinforcement mechanisms of different grouting materials were analyzed.The numerical simulation results showed that the proportion of tensile-shear microcracks,the distribution of microcrack inclination angles,and particle displacement vectors during the sample loading process were significantly influenced by the grouting material.Due to differences in the strength and bonding performance of the grout itself,the bonding pattern between the grout and the rock was altered,leading to changes in the movement of grout and rock particles and microcrack formation during the loading process,ultimately resulting in differences in macroscopic strength and failure modes.
rock mechanicsgrouting materialsgrout-rock bondingstrength propertynumerical simulationfailure mechanism
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