The Response Characteristic Research of Shallow-tunnel Timbering Structure under Earthquake Loads

With the rapid development of urban construction and development of underground space, the seismic performance of underground structures more and more attention. For these underground buildings, there is no mature seismic design methods, which makes underground seismic research is becoming increasingly urgent and important. Based on this, we mainly do the following work: examples of earthquake damage to the domestic and foreign representative of the tunnel project, tunnel damage types and characteristics as well as earthquake damage mechanism; using transient dynamic finite element analysis software ANSYS analysis method, country rock - lining 2D simplified model, the seismic response of tunnel lining tunnel in case of different depths, different lining thickness of the lining concrete level and different rock conditions to identify some of the basic law of the seismic response of the shallow tunnel; final analysis of the deformation and failure characteristics of arch tunnel under earthquake. Obtained through the above study the following conclusions: (1) increase the depth of the displacement response of the structure under seismic action is reduced, and the stress was increased with increasing tunnel depth, tunnel by external forces. in the increase, while the structure of Nei Lizhi also increase accordingly. (2) With the increase in the thickness of the tunnel lining, the lining of the displacement is reduced, but the reduced rate is not obvious. Lining thickness increases, the increase in the force of the tunnel invert, so the tunnel invert the same time should be considered in determining whether or not to change the lining thickness when the invert in which played an important role. (3) With the tunnel lining stiffness increases, the displacement of the tunnel lining decreasing trend, but the magnitude is very obvious, but the tunnel lining stress peak increase visible rely solely on the to improve lining stiffness to resist tunnel seismic loading The deformation effect is not ideal. (4) improve the level with the surrounding rock, tunnel lining displacement and the stress is reduced, and reduce by a big margin, improve the level with the surrounding rock, country rock bear most external load, the structure and the interaction of the surrounding rock decreases. (5) horizontal earthquake, parts of the wall of the four corners, side skirting and arch back arched tunnel is the weak point in the cross section; left, right hole invert, a major tensile stress, another major compressive stress, seismic design, while ensuring that the tensile and compressive properties of the double-arch tunnel invert.