The Response Characteristic Research Of Shallow-tunnel Timbering Structure Under Earthquake Loads

With the rapid development of construction in cities and the exploitation of underground space, the anti-seismic performance of underground constructions is being paying close attention to increasingly. A perfect method for the seismic design of underground structure was presented still, which makes the research about the seismic design of underground structure more important and urgent. The main achievements of this dissertation are described as follows:The summary of worldwide typical instances of tunnels behavior during earthquake, the characteristics regarding the tunnel damages during earthquake and classification are summed up, the damage mechanism of action from earthquake is described too. The transient dynamic method of ANSYS compute software is used to establish the planar model of surrounding rock & tunnel lining construction systems, discuss the tunnels behavior during earthquake under different depth, different lining thickness, different material concrete grade and diferent geologic conditions, find out some basic disciplinarians of seismic response of lining construction. At last discussed the characteristics regarding the tunnel damages during earthquake of the twin-arch tunnel.By the above study, the following conclusions are reached:(1)The displacement of lining structure during earthquake minished with depth increased, while stress and internal force increased.(2)The displacement of lining structure minished unnoticeably with lining thickness increased. Meanwhile, the stress of the tunnel invert increased, which we should consider when change the lining thickness of the tunnel with arch invert.(3)The displacement of lining structure minished very unnoticeably with lining stiffness increased, while stress maximum increased. So it's infeasible to resist deformation of tunnels on earthquake loads by increasing stiffness merely.(4)The displacement and stress of lining structure minished noticeably with surrounding rock grade improved, which as surrounding rock bears most of the loads, the interaction between rock and structure reduced.(5)On horizontal earthquake loads, the four angles of the middle wall, side wall footing and hance of twin-arch tunnel are the weak points on section. Moreover, one of the tunnel invert subjected to tension and another in compression, so we should ensure both tensile performance and compressive performance of tunnel invert in anti-seismic design.