Research On Stability Of Surrounding And Bolt Supporting In Soft Rock Roadway

With the development of mining engineering, more regionals in complicated geologicalconditions have been mined. Meanwhile, some issues are becoming increasingly acute, suchas surrounding rock roadway in fracture zone, the roadways with large deformation and softsurrounding rocks, the roadways in three soft coal seam. The different between the roof, thetwo sides and the floor lead to the influence on different parts of surrounding rocks, as a result,it expands the range of the destruction of the surrounding rock,so it should be studied by aintegrated system. During the different research methods in theoretical analysis, numericalsimulation, on-site observations and combining engineering practice, we have a deeper studyin soft rock roadway, it include the mechanical mechanism, the influencing factors and theirrelationships each other and so on of surrounding rock stability. The main research results asfollows:(1)With the method of numerical simulation, we get the interaction relationships andinfluencing factors among the roof, the two sides and the floor of the soft rock roadway fromFlac3D.Whether the two sides can be broken or not it is relate to the deformation anddestruction of the floor, similar trend is found in the sides have an impact on roof, thedifferent degree of influence owing to the different surrounding rock strengths. Analysing thelaw of rectangle surrounding rock, we get that the shape of plastic zone will be anapproximate ellipse when the surrounding rocks are relatively weak.(2) The mechanical model is based on the theory of natural balance arch, then wedefined the range and shapes of the soft rock roadway by theoretical analysis. Conclude thatthe homeostasis arch can be formed if only the roof failures, the limit homeostasis arch willappear if both of the roof and the two sides have been damaged, the limit homeostasis circlewhich is more bigger than the limit homeostasis arch and whose shape is an oval described asabove high below low can be formed if all of the the roof，the two sides and the floor havebeen destroyed.The formula of arch high of the limit homeostasis circle in the soft rock roadways has been deduced.(3) The research paper provide that the damage shape of soft rock roadway is an "oval",the broken surrounding rocks still exist a certain strength and also squeeze each other, thefocal point of bolt supporting is to control the ranges of plastic zone. Simulation found thatanchor supporting have an effictive control on the surrounding rock, it also can reduce theextent of damage and the amount of displacement.An experiment according to the theory of limit homeostasis circle and bolt supportingtechnology have been done in the south No.1main roadway of TaiPing coal. It prove that ourresearch have an effective impact on soft rock roadway.