Experimental study on acid erosion behavior of artificial rock joint plugged by MICP method

The microbially induced calcite precipitation (MICP) method has been widely used for rock mass and soil reinforcement, but the researches on its acid erosion durability are rarely reported. Therefore, the acid erosion tests on the MICP-treated artificial rock joint specimens are performed by considering different erosion solution pH values (4, 5 and 7) and erosion time (7, 14 and 28 d), then the dissolution of calcium carbonate within the specimens and the corresponding permeability evolution are investigated. The experimental results show that the amount of dissolved calcium carbonate in the specimens increases with the decrease of the erosion solution pH values and erosion time, and the calcium carbonate dissolution mainly occurs at the peripheral area around the specimen edges. Moreover, the average permeability of rock joint specimens decreases by 97% after the MICP treatment. Though the permeability of the MICP-treated rock joint specimens restores slightly after acid erosion, the permeability decrease is still more than 95% compared with that of the rock joint specimens before the MICP treatment, which indicates that the effects of the MICP method on sealing rock joints are good after acid erosion. The achievements can provide scientific bases for the application of the MICP technology for rock fracture sealing in rock mass projects.