Study On The Mechanism And Control Of Large Section Roadway Floor Heave In Complicated Conditions

Large section roadway floor heave control in complicated conditions is one ofthe problems needed to be solved when coal mines carry out the large mining heighttechnology. Taking the+540aclinic electric locomotive auxiliary transportation mainentry of coal mine in Wangzhuang, Shanxi province for the background,comprehensive methods application of field observation， theoretical analysis，physics experiment，numerical calculation contributes to the deformation law anddistribution characteristics of large section roadway in complicated conditions undermultiple influencing factors as well as its deformation and failure mechanism.Basedon this，the paper puts forward the control technology. The study gets the followingacheivements.1.Gaining the coal rock samples’ physical and mechanical parameters and itscompressive failure characteristics through uniaxial compression，triaxial compressionand brazilian split test of coal rock samples. The result shows that,coal rock samplespresent brittle tension failure under the circumstances of uniaxial compression, rocksturn into shear failure; when samples are broken，the sample still has carrying capacityafter destruction which is lower; along with the increasing of Ambient Pressure，themaximum bearing capacity and the retained intensity will accordingly enhance.2. Floor rock damage mechanics model is established, the calculating formula ofcritical axial stress, deflection and the critical analytical solution for the damage ofroadway floor mode are put forward. Floor heave controlling mechanism of flooranchor and relieving groove is raised.3. Calculation model of floor heave of large cross section roadway incomplicated conditions is conducted. The greater burial depth of roadway, the floorplastic zone is larger, the roadway deformation is more serious.horizontal stress has agreater influence on roadway roof and floor deformation.With the increase of lateralpressure coefficient, the deformation of roof and floor increase significantly; rockmass properties of floor has an especially impact on the stability of roadway. As Rockstrength weakening, the deformation becomes more serious and depth of damagebecomes larger. Damage of roadway always starts at the weak point.4. Numerical model of floor heave of large cross section roadway in complicatedconditions is conducted. Situations such as strengthening, pressure relief and joint support are considered to study the the stability of surrounding rock of roadway. Theresults show that: reinforcement method can control the floor heave of roadway, asfloor strength becomes higher, the controlling effect of floor heave becomesbetter.Floor heave decreases as depth of pressure relief groove increases, peak of floorheave horizontal stress moves to deeper position and peak of roadway sides verticalstress moves to further position of the roadway, the damage depth becomes deeperand the area becomes larger. joint support can effectively control the floor heave ofroadway, the peak of horizontal stress decreases, the stress concentration area reduces;the peak of vertical stress declines and damage area becomes smaller; deformation ofpressure relief groove diminishes.5. A joint support method is put forward to control floor heave of large sectionroadway in complicated conditions. Using bolt mesh spray as the basic supportingframework, with the help of pressure relief groove and floor grouting anchor cable,the deformation is well controlled, the industrial practice is very successful.The paper has65pictures，9charts and87references.