Research On Thermo-Mechanical Coupling Properties Of Resin Anchorage System In Deep Mine Roadway

In the coal mine roadway, supporting with resin anchor bolt is the main form of speedy drivage, and the stress-transfer is provide by the resin anchoring layer, so the mechanical reliability of resin anchoring layer is a important factors for roadway supporting. With the deepening of the coal mining, roadway excavates in high crustal stress and high temperature ground is growing more and more. The mechanical behavior of epoxy bonded bolt system which compose by anchor bolt, resin anchoring layer and the surrounding rock is different from the shallow strata, research on thermo-mechanical coupling properties are rare, and the cognize perceive of impact mechanism is prematuration.Some related question are researched by laboratory test, theoretical analysis and numerical simulation as followed.(1) A thermo-mechanical coupling experiment on mechanical property of resin anchoring material is carried out, and the thermodynamics influence of high temperature is quantitative analyses. Experimental results show that:when the temperature is rising between20℃and60℃, the strength resin anchoring material is descending in a rate of0.94MPa/℃, the elasticity modulus is descending in a rate of0.144GPa/℃, poisson’s ratio is rising in a rate of3.14×10-3/℃,and the thermal expansion is rising in a rate of0.559×10-6/℃.(2) A rheological experiment of resin anchoring material has been done; basis of the rheological experiment, a rheological model couple with thermo-mechanical effects is established. Experiments show that rheological behavior of resin anchoring material is affected by thermo and mechanical significantly. The higher stress and temperature is, the larger rheological deformation and steady-state creep rate are. When the thermal-mechanical coupled loads exceed a certain critical value, the steady creep will transform into viscoplastic accelerated creep; while it is less than the critical value, the steady creep will keep in a viscoelastic steady rheological. In a dead load of10MPa,20MPa,30MPa and40MPa, the certain critical value respectively are52.5℃,44℃,33℃and30℃.(3) Basis of the pulling test and numerical analysis of resin anchoring material bond with bolt under thermo-mechanical coupling, a point is developed that the tensile-shear strength and stiffness is the main factors of anchoring system capacity. when the temperature is rising between26℃and80℃, the tensile-shear strength and stiffness is descending respectively in a rate of0.428MPa/℃and1.38GPa*m-1/℃.(4) A thermo-mechanical coupling experiment on mechanical property of sandstone and mudstone is carried out to obtain the deformation parameters. Preliminary results show that:Compared with the resin anchoring material, the temperature has less impact on the deformation parameters of sandstone and mudstone. Then a simple mechanical model of interaction between full length anchoring bolt and surrounding rock is established. Basis of the experimental result of surrounding rock and resin anchoring material under thermo-mechanical coupling, consider of the in site temperature of surrounding rock, the simplify interaction model is analysed by numerical simulation, and the mechanism of epoxy bonded bolt system affected by high temperature in ground is being revealed.(5) In order to make sure the transmit effect of resin layer, the failure mechanism of resin layer is analyzed by elastic-plastic theory, combine with the numerical calculation results of interaction on resin anchorage and surrounding rock, a design method of anchoring parameters in high temperature mine is proposed.