Experimental study on grouting diffusion mechanism of fractured rock

Bolt-grouting support is a commonly used method for stabilizing surrounding rock in underground engineering. Its effectiveness directly influences the safety and stability of deep underground engineering. Field monitoring showed that the maximum deformation of the pump chamber reached 751.0 mm. The maximum depth of the severely damaged zone was 7.0 m. It is planned to implement bolt-grouting support in the pump chamber to control surrounding rock deformation. In order to clarify the strength variation law of the grouting diffusion zone and guide the bolt-grouting scheme, grouting diffusion tests were conducted. Tests revealed that the compressive strength of the grouted specimens decreased with increasing diffusion distance. According to the compressive strength within different diffusion ranges, it can be classified into initial decline zone, gradual decline zone, and edge zone. Based on the established strength variation indicators, it is found that the aggregate size has a greater influence on the grouting diffusion range than the water-cement ratio. In tests A1 to A3, the grouting diffusion range was increased from 800 mm to 1000 mm. The grouting diffusion range of tests B1, B2 and B3 was all 1000 mm. Based on the research of this paper, relevant suggestions for bolt-grouting support are put forward. After the implementation of bolt-grouting support in the pump chamber, the maximum surrounding rock deformation was 39.5 mm, indicating effective control of the deformation.