Application and prospect of hard rock TBM for deep roadway construction in coal mines

With increasing coal mining intensity, the number, length and depth of coal mine roadways is increasing drastically, the traditional drill-&-blast method and comprehensive mechanized driving method, and corresponding support methods are incapable of controlling the surrounding rock stability gradually. Hard rock TBMs (Full-face tunnel boring machine) have significant advantages in terms of fast advance rates, high support capacity, being favorable to environmental protection and low construction costs. Meanwhile some modern mines are possible target for TBM application. TBMs have been successfully used for some roadway and inclined shaft construction. Therefore, it can be foreseeable that the TBM tunnelling method will be the first choice and preferred future method for deep rock roadway construction in coal mines. However, because of the complicated construction environments, many technical challenges are encountered during TBM tunnelling in deep roadway including the presence of: (a) mixed and changing grounds; (b) high geostress; (c) squeezing deformation and the induced TBM entrapment or overstressing on supports; (d) fractured and faulted zones; (e) special requirements for TBM assembly, explosion-proof, influences of roadway or cavern groups, drainage due to the construction environments in coal mine. Therefore, in order to cope with these challenges in deep roadway tunnelling, the following scientific problems are identified as needing urgent examination: ground stress distribution and geological conditions investigation of deep roadway; interaction mechanism between the surrounding rock and the TBM; safety control for surrounding rock stability; informatization construction, optimization decision and intelligent control for TBM tunnelling. Some research progresses are also presented. Solution to these problems will provide an important theoretical foundation for application of TBMs in deep coal mines.