Study On Risk Analysis And Security Early Warning Index For Large Dam

It's an urgent subject for investigation to hold dam safety status and degree of its risk completely and scientifically, and warn risk sources in time. On the base of the previous work, slip and seepage risk analysis model of earth dam is founded, simultaneously, security early warning index of concrete dam and earth dam is lucubrated. In this paper, the following contents are included.Firstly, according to physical character and engineering operation condition of earth dam, main invalidation modes about earth dam engineering are investigated. Aimed at two main invalidation styles: slip and seepage, the risk computation models are founded correspondingly, and then they are adopted to research on slide instability risk coefficient for Fuhuashan dam. The research shows that, although Fuhuashan dam is satisfied with the least safety coefficient in traditional meaning, slip risk also exists based on the result of risk analysis.Secondly, in the foundation of early warning system theories about military affairs, economy and disaster, dam security early warning system is establish, three dimension and one dimension early warning principle is discussed, concept of early warning index is expatiated. Early warning index is estimated from dam safety monitoring index, commonly methods to confirm monitoring index is discussed in dam security early warning system.Thirdly, one of sixty-four-dollar questions on security early warning for concrete dam is lucubrated—to confirm security early warning index for concrete dam. Integral stability against sliding of the No.3 powerhouse dam Section in left bank of the Three Gorges Project is calculated with discontinuous deformation analysis and strength storage safety coefficient method. The phase of dam which is at elastic phase, elastic-plastic phase or unstable failure phase with great distortion is confirmed by sliding criterions combined with relationship between displacement of enactment measure points and strength storage safety coefficient. Strength storage safety coefficient in limit loading state is gained. In addition, primary monitoring index and secondary monitoring index of this section displacement are concluded. Consequently, its deformation early warning index corresponds to primary monitoring index.Finally, one of sixty-four-dollar questions on security early warning for earth dam is lucubrated—to confirm security early warning index for earth dam. With the result of seepage finite element method, key permissive permeability gradient of the body and the foundation is estimated for Fuhuashan earth dam, combined with sensitivity analysis and qualitative risk analysis. The value is confirmed as seepage early warning index of earth dam.