Research On Mechanical Effect Of Prestressed Anchor Support And Surrounding Rock Control Effect In Arbitrary Installation Form

With the increase of coal mining intensity and the depletion of shallow coal resources,deep mining has become the mainstream trend.Under the influence of deep high ground stress and strong excavation unloading,surrounding rock cracks develop and stability control is more difficult,which also puts forward higher requirements for traditional anchoring technology.To solve the above problems,this thesis adopts the research method combining theoretical analysis and numerical simulation.The distribution characteristics of stress field in surrounding rock support under single bolt,multiple bolt and bolt-cable coupling are analyzed.Based on the typical roadway of Zhaolou Coal mine in typical Juye mining area,UDECTrigon numerical simulation method is used to study the mechanical effect of prestressed bolt support and the control effect of surrounding rock.The main research work is as follows:1.Based on the basic theory of elasticity and superposition principle of mechanics,the mechanical analysis models of surrounding rock supported by single bolt and multiple bolts with arbitrary installation form are constructed respectively.The theoretical analytical solutions of bolt body stress and surrounding rock supporting stress are derived.The influence of anchorage design parameters such as bolt installation angle,pretension,anchor length,bolt length and spacing on the distribution characteristics of surrounding rock supporting stress field is analyzed.Furthermore,numerical simulation was carried out by FLAC3 D software to verify the validity of the theoretical method.2.On the basis of the previous research work,considering the influence of anchor cable support,a mechanical analysis model of surrounding rock under the action of bolt-cable coupling support is constructed.The theoretical calculation formula of surrounding rock support stress under the coupling action of bolt-cable is derived.Considering the influence of the number of cable roots and spacing,four kinds of bolt-cable coupling support layout schemes are designed.Further,considering the influence of different bolt and cable pretension,the distribution characteristics of surrounding rock support stress under different bolt-cable pretension combination schemes are calculated and analyzed.3.Based on the typical roadway of Zhaolou Coal mine in Juye Mining area,UDECTrigon numerical simulation method is used to consider the influences of different anchorage design parameters and reveal the influence law of different parameters on the distribution of stress field in surrounding rock support.Furthermore,considering the influence of different ground stress,side pressure coefficient and anchorage design parameters,the numerical simulation of the whole process of roadway excavation and support in fractured surrounding rock was carried out.The influence law of different parameters on the control effect of roadway surrounding rock is revealed.