Abstract: To study the instability mechanism and control method of roadway regenerated roof in random joint rock, a random joint simulation program has been written to build a random joint numerical roadway model through FISH language embedded in UDEC software, combined with the Monte-Carlo simulation method and based on statistical result of joint parameters in an excavation roadway of Beizao coal mine. The stability failure process and support form of roadway regenerated roof has been simulated in the model, and the numerical simulation result has been tested by engineering application. The research has shown that some small rock blocks in the support roof are easy to slide and to be caved, then key rock block slides down along the joint interface, and when one end of key rock block is separated from the roadway wall, the whole roof loses its stability and begins to collapse. The proper roadway support form under regenerated roof is the combination of cable anchor and shield support, which can control the roof deformation and prevent the caving of broken small rock blocks.

Key words: random joint rock, regenerated roof, roadway excavation, instability mechanism