Study On Reinforced Supporting Technology Of Inner Interlocked Tail Road On Island Working Face

Skip-mining way not only can solve the problem of succeed tensionbetween mining and tunneling effectively, but also can reduce the stressconcentration in mining roadway. So this technology is favored by many coalenterprises. But it forms island working face inevitably, which both sides of theworking face are mined-out area at least. Compared with ordinary working face,island working face affected by lead abutment pressure of mining and lateralabutment pressure of mined-out area, which leads to a high degree of stressconcentration. It is a serious challenge to control surrounding rock and tomaintain mining roadway.Although Chinese coal enterprises have much success experience in miningisland working face, obtained a quantity of measured data and research results,most of them are strengthen anchorage supporting and grouting reinforcement toimprove the self bearing capacity of rock mass anchorage in tunnel on theworking face, to control the deformation of surrounding rock of. Although thealternate interior tail roadway and working face crossheading belong to the sameroadway, but different position and different use decision the methods ofstrengthening of anchor and grouting reinforcement are not applicable to thealternate interior tail roadway surrounding rock, has not been effectivelyresolved the problem of serious deformation of roadway surrounding rock.In this paper, the engineering background is the inner interlocked tailroadway of80704working face, which in the second mine of Yangquan Coal Industry. Through the system research of seam conditions, mining technologyand current supporting way of15#coal, analyzed the overburden structuralfeatures, distortion and breakage form and influence factors of the isolatedisland working surface in theoretical, mastered the control theory of surroundingrock. The author proposed a new rock control technology firstly, combined withthe actual situation, which use section assembled high strength reinforcedconcrete pillars to reinforce the internal tail roadway. Using finite elementsoftware ANSYS to establish different bearing area of Concrete pillar model,observed the destructions after loading the force, determined the diameter of theconcrete pillars main carrying surface is0.3m. According to the roadwaysurrounding rock stress situation, built the numerical simulated model of80704face through FLAC3Dsoftware, simulated the two different cases of using theoriginal tail roadway internal anchorage support programs and strengthensupport program, the analysis showed that after using concrete pillar reinforcedsupport, the roadway plastic zone distribution reduced significantly, the relativedisplacement of the top and bottom reduced by65%,the contraction of bothsides reduced by60%, roadway deformation is controlled within a reasonablerange, ensured the effective ventilation section. Determined the pillar layoutprogram of the inner interlocked tail roadway of80704working face finally, andtook rock pressure observation regularly. According to the observation data,distortion and breakage phenomenon, force deformation of concrete pillar andeffective ventilation section analyzed the effect of strengthening support in thetail roadway.Field test results showed that roadway surface displacement is small duringthe observation, did not appear obvious floor heave phenomenon, bottom ofpillars had not inserted the floor, only a few top parts of pillars appeared skinshedding phenomenon, but it does not affect the stability of the surrounding rock,basal area remained at least7.2m2generally, necking-down rate is only18%. Sothe effect of section assembled concrete pillars for rock stability control is remarkable, verified that section assembled concrete pillars will deliver the roofpressure to the central floor to control the floor heave and reduce the two sidesforces at the same time, then control the relative shifting amount is right.The results of this study have wide application prospects in the area ofYangquan, and to provide reference for similar tunnel face in other supportingproblem.