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Abstract To solve surrounding rock control problem in super-high roadway，the ultrahigh segment(section size is 5.25 m×8 m) of No. 5201 main transport roadway in Wujiagou mine was selected as research object. Response characteristic of coal side un-stable triangle block was analyzed by UDEC and balance arch theory. The results showed that：(1) Coal side force state is like unconfined uniaxial compression，the failure form is triangle block shear slip，whose angle is 45°－?/2 in the direction for lateral wall. (2) The vertical stress and the horizontal stress difference increases gradually in deep part，which constitutes main force source of un-stable triangle block slip. (3) Subsidence curve and horizontal displacement curve in coal side both have obvious inflections，which transfers to outside gradually with roadway height increasing. (4) Maximum width and roof pressure of un-stable triangle block add with roadway height increasing，stability gradually drops. It proves that：(1) High performance，high pre-stress bolt could enhance surrounding rock characteristics，decrease roof pressure and keep integrity of un-stable triangle block，and with middle and lower bolt in coal side pass through the shear slip face，also could resist shear and slip of un-stable triangle block. (2) Diagonal cable beam structure could be anchored in the shoulder and floor stable area out the caving arch，develope advantage of high strength，increases friction of un-stable triangle block. Based on this，the support technology of high strength and high pre-stressing bolt net bar and sides diagonal cable beam is proposed. During the period of driving influence，roof-to-floor relative convergent velocity is 4.1 mm/d，both sides maximal relative convergent velocity of sides is 4 mm/d，roof-to-floor relative convergence is 104 mm，both sides relative convergence is 150mm，the total roof separation was 3.5 mm，roadway self-stable period after it was dig out for 10 days，integrity of un-stable triangle block is well and slip sign is not obvious.
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2015, Vol. 34 
