Research On Mechanical Properties Of Granular Concrete And Anti-explosion Performance Of Tunnel Lining

In In recent years,the field of tunnel and underground engineering has developed rapidly,which has provided great convenience for people's life and production.At the same time,the tunnel construction and operation of a variety of safety hazards have gradually attracted people's attention.In order to explore the anti-explosion properties of granular concrete as tunnel lining and its influencing factors,this paper experimentally studies the mechanical behavior of granular concrete at static and different strain rates,and establishes the Z-W-T constitutive equation of granular concrete,using which the numerical simulation of tunnel lining is carried out.Using MTS universal testing machine,based on the relevant knowledge of material mechanics,the relevant mechanical parameters of particles and ordinary concrete are obtained The static stress-strain relationship and failure mode of granular concrete are compared and analyzed.The experimental results show that the granular concrete specimen only appears obvious failure when the strain rate is 448.8s-1 and remains intact block,while the ordinary concrete specimen has no bearing capacity at the strain rate of 116.01s-1.At the same time,with the increase of the strain rate,the ordinary concrete is broken from fragment to powder.Both kinds of concrete are strain rate sensitive materials,that is,the peak stress of granular concrete and ordinary concrete increases with the increase of strain rate.Under different strain rates,the dynamic stress growth factor DIF increases with the increase of strain rate,and the linear curve and relational equation between the two are obtained by fitting.The strain rate sensitivity of granular concrete compressive strength is not as good as that of ordinary concrete.Based on Z-W-T constitutive relation,under the condition of known each physical quantity,makes the simplified Z-W-T contains A constitutive relation equation,A?????E0?E1??1?E2??2 eight parameters,sets up A dynamic approximate equivalent particle concrete constitutive relation,Relevant data are obtained through experiments and Origin software is used to obtain the value of each parameter of the constitutive relation.Meanwhile,the dynamic constitutive equation can describe the information before and after the peak,which provides a good equation for the subsequent simulation and is convenient for generalization.By establishing the improved Z-W-T constitutive relation,the anti-explosion performance of granular concrete tunnel lining structure is simulated under different equivalent mass of TNT and different explosive positions.And compared with ordinary concrete;The simulation results show that:With the increase of TNT equivalent mass,the maximum equivalent plastic strain of granular concrete as tunnel lining layer is 0.8015,0.8385,0.8840,0.9159,0.9068,0.9293,0.9724,0.9751,0.9604 and 0.9342 of the control group,respectively.Granular concrete is superior to the control group as tunnel lining layer.For the change of explosion position,the maximum value of equivalent plastic strain after explosion generally increases.When the equivalent mass of TNT is 100kg,the maximum value of equivalent plastic strain of granular concrete as tunnel lining layer is 1.406 times that of equivalent plastic strain of corresponding equivalent mass TNT in the following scheme.