Dynamic Response Analysis Of Underground Cylindrical Composite-lining Cavern Subjected To Seismic Waves

The dynamic response of the underground cavern subjected to the earthquake waves has been one of the most striking research topics in domestic and overseas for many years, it has the important guiding significance to the anti-seismic research and design of the underground excavation engineering project.By using wave function expansion method, dynamic response of a underground cylindrical composite-lining cavern in an elastic space subjected to earthquake waves(the SH-wave, the P-wave and the SV-wave ) is analyzed, the composite-lining is composed of flexible lining and rigid lining, and the corresponding series solution is obtained. Apply the series solutions to compile computer program by means of the mathematics software Mathcad, and then makes parametric analysis in allusion to its result, discusses the main factors affecting the dynamic stress concentration factor of the surrounding rock and the lining structure, such as the frequency of incident waves, the ratio of thickness of the flexible lining to the rigid lining, and the elastic modulus, poisson's ratio and density of the flexible lining as well as the distribution of the dynamic stress around the cylindrical cavern. The topic of this paper is converted to the dynamic response of the cavity, rigid-body and single-lining cavern in an elastic space by doing some parameter variation, and its results are completely consistent with the previous research achievement, so the validity of this thesis is proved.The calculating results show that: compared with the single-lining, the composite -lining composed of the flexible lining and the rigid lining really brings the surrounding rock's self-supporting ability into full play effectively and reduces the dynamic stress concentration factor of the lining structure, and the effect is remarkable when the frequency of the incident waves is low. All of this indicate that the composite-lining have a good action to underground cavern to resist against earthquake. Among this three earthquake waves, the decreased degree of the dynamic stress is smallest for SH-wave, it's next for P-wave, and it's biggest for SV-wave. Furthermore, it is obtained the optimal value of the ratio of the thickness of the flexible lining and the rigid lining and the ratio of the elastic modulus of the flexible lining to the rigid lining, and at the same time discovers that the poisson's ratio and the density of the flexible lining have a slight influence on the dynamic stress concentration factor of the surrounding rock and the lining structure when the frequency of the incident waves is low. moreover, its effect is negligible when the frequency of the incident waves is high.