Study On Ultimate Failure State Of Concrete Surge Shaft

With the increasing demand for electricity in our country, more and more hydropower stations are being built. surge tank plays a very important role in ensuring the normal operation of the hydropower station, its development is becoming more and more quickly. The development trend of surge tank shows that the diameter is bigger and bigger, the arrangement and structure is becoming more and more diverse.Traditional analysis methods, namely, thin wall cylinder method can only analyze small surge tank, For the large surge tank, if traditional structure mechanics method is alone adopted to design and calculate the surge tank, the result often shows a big deviation in comparison with design requirements. Finite element method has been widely used in practical engineering, finite element method also can be to introduced to solve large diameter surge tank. The main research contents in this paper are showed as follows:1.To basically introduce the surge sharf’s basic function and its structure, and to introduce two kinds of analysis methods for surge sharf:thin wall cylinder method and finite element method, and then to state the constitutive relation, the yield criterion and failure criterion of surge tank’s main materials concrete.2. Choose a three cent point loading test beams, and use Willam Warnker five parameters failure criterion to proceed numerical simulation analysis on this beam. Through comparing the ultimate load, the deflection and the load curve of numerical simulation with the experiment results, the results are coincident. It shows that the Willam Warnker five parameters failure criterion is well adapted to simulate the material mechanical behavior of concrete.3. Use the finite element method to analysis a cylindrical surge sharf in numerical simulation. Firstly, regardless of the effect of surrounding rock, under the condition of the lining working alone, this paper shows the lining cracks water level and the limit water level. Secondly, considering the surrounding rock and lining’s working together, this paper obtains the surrounding rock elastic modulus range in the condition that the lining works without cracks. Finally, this paper shows the lining’s working states when the elastic modulus of surrounding rock is a certain value, and shows the lining crack development, changes of stress and displacement in different water levels, different surrounding rock elastic modulus.