Study On Applicability Of The Indices For Varied Damage Locations On The Concrete Arch Dam

As we all know ,the concrete arch dams have fine bearing capacity, but actually the harm resulted in damage of the arch dam crack and the unstability of arch dam shoulder or foundation can not be ignored. Now the dam safety monitoring system which can timely detected and analyse the damage has been widely used all over the world. Using dynamic detection technique to analyse the damage of the dam is gradually becoming a research hotspot in this domain. Much theory studying on this method shuold be carrying out before going to apply better in practice.In this paper, the main content is respectively using the indices methods to detect the varied damage on arch dam(including the cracks in various locations on the dam body and the dam shoulder harm),carrying out the effect distinguishing,finally choosing out the locations which can be detected better using this technique.And then using numerical model with the elements getting in touch with together to simulate crack on the dam body. Building eight kinds of numerical value models for the damages of different location and build the corresponding undamaged model with the identical element node of the damaged model. Respectively caculating every order modal of all kinds of the damaged and corresponging undamaged numerical value model,and then extracting out the relevant modal parameter to be used in the method to distinguish the damaged location. Comparing the different effect of varied damaged locations.Regarding the downstream surface crown's crack damage, low-order presents miscarriage of justice with the Beta law and the modal curvature law, the strain modality combination indices method recognition effect is very good; Regarding each kind of crack damage of the upstream surface's middle section, recognition effect is quite good with these three kinds of indices, can distinguish the damage location, and the miscarriage of justice and error is limited; Regarding the downstream surface base and the upstream surface base's crack damage, recognition effect with three kinds of indices is different, the Beta law's result is the best.Dam shoulder's unsteady situation adopt the method that reducing the stiffness to carry out a simulation , analyse the modal of the numerical value model on the damaged and undamaged condition. Calculating the frequency of first ten order, the fall of every order frequency instruct loss out. In this paper, I attempted to adept the loss indices to identificate the damage location, finally find the identification effect is bad with beta law and modal law of curvature, but the result with the method of combined strain modal law, can basiclly distinguish out the dam shoulder loss location.