Abstract: In this paper, based on the growth law of support circulation resistance in the fully-mechanized mining face of No.2-2 coal seam, Ordos basin, the fracture structure model of weakly cemented roof in shallow coal seam was built, the supporting strength formulas of hydraulic support in different roof movement stages were derived, and were compared with the field observations. The results show that there exits a rock beam composed of some squeezing rock blocks in the weakly cemented roof, which can be seen as a similar basic roof. The rock beam can not only transfer the horizontal force, but also reduce the impact of overlying strata on support. During the mining process of shallow seam, the moving process of weakly cemented roof can be divided into three stages. Stage one, the immediate roof caves, and the overlying sandy mudstone breaks, squeezes and generates separations. Stage two, similar basic roof breaks and forms the rock beam. Stage three, the basic roof subsides and impacts the support. With the working face advancing forwards, the growth of the support resistance can also be divided into three stages, which are initial increasing stage, slow increasing stage and significant increasing stage. This research can provide reference to roof control design, support selection, et al, in shallow seam of Ordos Basin.

Key words: shallow seam, weakly cemented roof, similar basic roof, fracture structure