The Research On Characters Of High-strength Yielding Pressure Bolt And The Coupling Function Of Yielding And Discharging Pressure

High ground stress and large deformation are the two important problems which wehave to face and to be solved during the supporting process in deep buried tunnel. InChina, we are in the vigorous development time of coal industry, deepen the research ofdeep-buried roadway has important practical significance. This thesis through theexperiment of pressure relief pipe’s compression, high-strength bolt pulling experimentand numerical simulation of ADINA and combined with existing support theory,research on a roadway support technology under coupling support between drillingdischarging pressure and new type yielding pressure bolt.First, through yielding pressure tube’s compressing experiment and yieldingpressure bolt experiment, this thesis analyses the functional characters of yieldingpressure bolt and the stress-strain laws, deduce the yielding pressure tube’s structurerelationship which inosculate with the experiment’s result; through theory analysis andnumerical simulation, analyses drilling discharging pressure’s influence towards thetunnel surrounding rock’s stress field and strain field, and further expatiate yieldingpressure aperture, crustal stress and seam strength’s influence relationship towardsyielding pressure radius; on the basis of theoretical study on the stress distribution ofroadway surrounding rock, yielding pressure bolt’s support mechanism, the relationshipbetween intensity of the supporting system and intensity of surrounding rock’s anchor,through a series of analysis on drilling discharging pressure and yielding pressure bolt’scoupling support simulative contrast, study yielding pressure point, yielding pressuredistance, discharging aperture and yielding pressure bolt’s length, discharging hole andyielding pressure bolt’s length, array pitch between discharging hole and yieldingpressure bolt, yielding pressure bolt’s diameter and so on,showing the influencing lawstowards the changing of these different influencing factors on the effect of couplingsupport. In the meanwhile, combined with real construction cases to prove that themethod is applied to a certain extent of coupling support for deep-buried roadway. Mainconclusions are as follows:(1) Let pressure anchor rod has unique let pressuredeformation features, both can protect anchor rod body and can actively controldeformation of roadway, conducive to the stability development of roadway rock;(2)Radius of drilling unloading pressure area, drilling radius, and crustal stress are in proportional relationships, inverse relationship with cohesion of coal seam and has notmuch relation with frictional angle of surrounding rock.(3) The elasticity of yieldingpressure rock bolt, the greater distance of yielding pressure, the higher height ofyielding pressure points, the larger coefficient of yielding pressure of yielding pressureefficiency,the more stability of roadway, anchoring body has more yielding pressurestoring space to resist dynamic pressure or rock body vibration, or other forcesdisturbance, but anchor rod yielding pressure efficiency coefficient should control in2.5~4.0;(4) The influence of pressure relief hole and yielding pressure bolt’s designparameters toward supporting effect of deep buried laneway has a certain regularity.With the increase of yielding pressure hole’s diameter and length, the stress of lanewaysurrounding rock, the quantity of deformation has a changing rule from decrease toincrease. The stress of laneway surrounding rock and the quantity of displacementdecrease with the increase length of anchor and the influence effect decrease gradually,appropriate length of anchor bore should be able to make its anchor end stay in elasticzone of surrounding rock. Diameter of bolt has a certain influence towards lanewaysupport effect, but the effect is not obvious. The distance between yielding pressure holeand anchor has a certain bound toward the effect of laneway support, immoderateincrease or decrease the distance both have bad influence on supporting effect. Pressurerelief hole distance between bolt and the scope of effect there is a roadway, excessiveincrease or decrease the distance between is unfavourable to the supporting effect ofroadway.