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To focus on the key scientific problem of process control of dynamic catastrophe of high dams, presented for the first time are the modelling theory of liquid-gas-solid tri-phase coupling of the air-cushion isolation control of high dams and its numerical simulation method, and theoretical description of the complicated dynamics problem of the tri-phase coupling-thermodynamics state-material-contact bi-nonlinearity, as well as the simulation analysis of the key effects of dynamic catastrophe of the air-cushion isolated high dam engineering. The analytic solution of plane-wave with rigid-dam body was created. The simulation comparison of dynamic catastrophe processes of 305 m Jinping arch dam with and without seismic control was carried out, and the results were basically in agreement with that obtained from the large shaking table tests, and verify each other. The entire air-chamber and optimized air-cushion with varying thickness were presented to develop a optimization method. The large shaking table tests of the isolated dam model, which is satisfied with the basic dynamic similarity relations, were performed for the first time. The test data seemed to be convincing and were in agreement with the dynamic simulation results of the tested model, thereby providing an experimental verification to the simulation theory and method. The combination experiments of theoretical model and physical model demonstrated that the hydrodynamic pressure of high arch dams can be reduced by more than 70% as well as the first and third principle stresses of the dam body reduced by more than 20%-30%, thereby the global anti-seismic capacity of the high dam being improved significantly. The results have shown that the air-cushion isolation is the prior developing direction of structural control technology of high concrete dams.air-cushion isolation of high concrete dam, liquid-gas-solid multi-field coupling, material-geometry bi-nonlinearity, large shaking table test, hydrodynamic pressure Citation:Liu H W, Zhang S J, Chen J, et al. Simulation analysis theory and experimental verification of air-cushion isolation control of high concrete dams.

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The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology, which was used in health monitoring of Wu Gorge Bridge on Yangtze River and a large dam successfully, have been investigated. A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model, as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented. A series of verification experiments, including mechanical experiments and mechanics-optics coupling experiments, have been preformed. The results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close agreement. Both the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system. optic-fiber sensing, mechanics-optics coupling, micromechanics, health monitoring, concrete structure, crack detection Citation:Liu H W, Chen J, Sun M, et al. Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing.

A three-dimensional (3D) finite element model of air-cushion isolated arch dam is presented with the nonlinear gas-liquid-solid multi-field dynamic coupling effect taken into account. In this model, the displacement formulation in Lagrange method, pressure formulation in Euler method, nonlinear contact model based on Coulomb friction law are applied to the air-cushion, reservoir and contraction joint domain, respectively. The dynamic response of Jinping I arch dam with a height of 305 m is analyzed using the seismic records of the Wenchuan Earthquake in 2008. Numerical results show that the air-cushion isolation reduces significantly the hydrodynamic pressure as well as the opening width for the contraction joints of high arch dam.