Experiment And Dynamic Response Analysis Of Immersed Tunnel Under Earthquake

With the rapid development of economy in our country, it has become increasingly important to build a transportation network extending in all directions. The advances in transportation can lead to the new ways of crossing rivers. The emergence of immersed tube tunnel greatly changes people's needs and reduces the impact on the surrounding environment to solve the shipping problem of the large area of waters at the same time.As a country possesses vast territory and abundant resources, China has a long coastline, so the development of underwater traffic form will alleviate China's regional traffic pressure in a wide range. The immersed tube tunnel has small requirements for foundation, especially for soft foundation or when the riverbed depth is shallow. Sometimes, the tunnel is built in earthquake-prone seismic belt, so the earthquake has particularly significant influence on it. The geographical location for immersed tube tunnel determines that its importance cannot be ignored. In the event of damage, it may generate an immeasurable loss. Thus, the analysis of dynamic response of immersed tube tunnel under the effect of earthquake is very important.At present, China has obtained certain achievements on the study of land tunnel, but analysis of dynamic response of the immersed tube tunnel is still very few. To this end, this paper to complete the following works based on the results of previous studies:(1) Carry out the shaking table test of dynamic soil structure interaction of the immersed tube. Through analyzing the two kinds of site conditions of saturated sand and unsaturated sand under horizontal earthquake, the discipline of seismic response of the surrounding soil and immersed structure can be obtained. At the same time, the experiment was carried out on the two conditions of considering water and not considering water, and the research on the response of the tunnel under the influence of different earthquake intensity was conducted.(2) Demonstrate the feasibility of artificial boundary. Through adopting the viscoelastic artificial boundary, applying the numerical simulation by using the large finite element software ADINA, and comparing the dynamic responses of horizontal and vertical earthquake movements of immersed tunnels, the reliability of the experiments and the feasibility of numerical simulation are testified. Moreover, the key points of immersed structures are analyzed and discussed in detail in the research, and the influence of the key units under the earthquake was concluded. At the same time, the influence of different water depth on the immersed tunnel is also considered.By means of experiment and numerical simulation, this paper obtains the general rule of immersed tube tunnel under earthquake excitation, which can provide reference and basis for practical engineering design and construction.