| Tunnel and underground structures help human beings to greatly expand their living space and reasonably utilize the three-dimensional space, they are becoming important symbols of economic development, scientific progress and contemporary civilization as well. However, frequent great earthquakes and fast-changing underground structures are two aspects of a main contradiction. Therefore, to resolve these problems reasonably and brilliantly is the purport of this dissertation. By using methods of field investigation, theoretical analysis, numerical calculation and shaking table test, the global model seismic disaster instances of fault-crossing tunnel and underground structures were classified and summarized. Based on seismic damage mechanism and earthquake influencing factors, post-seismic restoration measures together with aseismic and damping measures were researched and developed. Moreover, calculation model of damping coat effect and mechanical model of aseismic joint were built by 2-D and 3-D numerical and theoretical analysis respectively. Based on traditional aseismic and damping measures, late-model measures for fault-crossing tunnels were researched and developed. Afterwards, numerical calculation validated the new type aseismic and damping measures. Finally, in order to prove and summarize the above research, large-scale shaking table tests for seismic damage mechanism and control measures of fault-crossing tunnels were conducted. The main jobs, conclusions and achievements are described as follows:(1) Worldwide seismic damage model instances of fault-crossing tunnel and underground engineering are collected and divided into six parts such as overview, patterns, classification, mechanism, influence factors and restoration measures. Generality and individuality of seismic damage instances together with awareness inclination and research direction of academics in different countries are deeply analyzed. Seismic damage mechanism and influence factors are analyzed on the basis of seismic damage overview, patterns and classification. Furthermore, these series research jobs are able to guide numerical calculation and model test to achieve seismic damage patterns reappearance and promote research for aseismic and damping measures.(2) As the basic aseismic and damping measure in the cross direction of tunnel structures, damping coat has different shapes and materials. The range of values of geometric and material parameters in numerical calculation model are defined to constitute many dimensionless elements for evaluating damping coat effect. The bending moment ratio of tunnel structures cross-section with and without damping coat is the function coefficient of damping coat effect. Finally, calculation model for damping coat effect is put forward to research and develop more effective and economic damping coats and validated by numerical calculation and shaking table test.(3) As the basic aseismic and damping measure along the longitudinal direction of tunnel structures, the aseismic joint endows tunnel structures with malleability and flexibility. Generally, there are flexible materials and connectors in aseismic joint gaps, thus, the mechanical calculation model for aseismic joint is put forward to evaluate lateral mechanics behavior of tunnel structures, which is on the basis of all the assumptions of the Bernoulli-Euler theory of beams and the Winkler theory for the beam on an elastic foundation. Based on this model, the fault maximum action width is defined when a single effective aseismic joint locate in the middle of fault. The new method of dislocation arrangement of aseismic and damping measures relative to fault and compound measures are put forward, they are validated by numerical calculation as well.(4) In order to fully validate correctness of the above research achievements, seismic damage mechanism and counter measures for fault-crossing tunnel structures are conducted by shaking table tests. A fault sliding device is invented to be used in shaking table tests and it can drive fault-slip by seismic waves under the circumstance of a single model box on a signal shaking table. Fault-crossing tunnel structures without aseismic and damping measures act as the contrast example to research the mechanism and effect of damping coat, aseismic joint and casing-shape deformable measures in cross section and longitudinal direction of tunnel structures. Besides, temporal and spatial damage process law of tunnel structures and surrounding rock are researched by these series of shaking table tests. |
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