Research On Optimization Of Shock Absorption Scheme For New Primary Support Structure Of Tunnel

In recent years,with the rapid development of underground traffic,more and more tunnels have been constructed.At the same time,China is a country with frequent earthquakes.Therefore,the research on shock absorption of tunnels has become an increasingly important issue for scholars.Under this background,relying on the new high strength foam concrete material,the tunnel shock absorption structure that combines the primary support with the shock absorption layer is proposed,which is called the new primary supporting structure,and the dynamic response rules and the optimal primary support thickness of the tunnel are explored under this structure.In order to achieve this goal,this paper uses the method of rock mechanics and finite difference software FLAC3 D to construct and calculate the model.The main contents and results of the research are as follows:(1)The boundary conditions and damping parameters of the model are determined by studying the previous data and combining the purpose of the paper.The back analysis,filtering and baseline correction of seismic waves are also carried out.(2)The dynamic response rules of tunnels under different seismic intensity,different surrounding rock grade and stiffness of new primary support are explored from the angle of safety factor,maximum principal stress and acceleration,and some suggestions are also made for t the range of optimal thickness of new primary support.(3)Then the sensitivity of tunnels under different variables is further studied from different perspectives,and the variation law of sensitivity of tunnels under different variables is summarized.It is concluded that the most sensitive variable for tunnels under different angles is seismic intensity.(4)Finally,in order to highlight the rationality and superiority of this scheme design,it is compared with the conventional construction scheme and other schemes with shock absorption measures.It is found that the proposed scheme has good shock absorption effect,at the same time,the construction cost is also reduced due to the less construction procedure.After research,under different working conditions and different research perspectives,using high strength foam concrete material to combine the primary support with the shock absorption layer,it shows a good shock absorption effect,and reduces the construction cost and improves the economic efficiency.