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

Microbially induced calcite precipitation (MICP) that utilizes the bio-mineralization process to generate calcium carbonate, is a method for reinforcing the geomaterials. It has been widely used in the field of soil reinforcement, but the research results on its application in the field of rock mass plugging are not common, and the researches on the acid erosion durability of the MICP method are rarely reported. Therefore, acid erosion tests on MICP-treated rock joint specimens were performed by considering different erosion solution pH and erosion time, then the dissolution of calcium carbonate in the specimens and the corresponding permeability evolution were investigated. The experimental results showed that the amount of dissolved calcium carbonate in the rock joint specimens increased with the decrease of the pH value of the erosion solution and the erosion time, and the calcium carbonate dissolution mainly occurred at the peripheral area around the specimen edges. The average permeability of the rock joint specimens decreased by 97% after MICP treatment. Though the permeability of MICP-treated rock joint specimens restored slightly after acid erosion, the decrease of the permeability was still more than 95%, which indicates the good effect of the MICP method on sealing rock joint after acid erosion. The achievements can provide scientific bases for the application of MICP technology for rock fracture sealing in rock mass projects.