Stability Analysis For The Surrounding Concrete Cracks Of Spiral Case

Because of direct contact between steel lining and surrounding concrete,some cracks would be appear in the surrounding concrete of complete beating spiral case under the internal water pressure.If considering the pulsation pressure,maximal internal water pressure and other special conditions.the strainedcondition of spiral case could be more complex.So the research for stability analysis of surrounding concrete cracks of spiral case is very necessarily.There is lack of existing research results based on fracture mechanics and there are very few of research on stability of cracks of concrete of spiral case.Focused on this question,a 3D-nolinear simulation model has been established to calculate the stress intensive factor and analysis the stability of concrete cracks of complete beating spiral case.The following aspects are studied:(1) Using the cycle symmetry method,the FEM section model of has been established and a non-linear finite element analysis has been carded on to anslyze the complete beating spiral case.The distribution of cracks in concrete outside the spiral case could be given.(2) The FEM model of spiral ease with cracks has been established based on the generalized for cracks.The stress intensive factor of concrete cracks under some load conditions has been calculated and the stability analysis of concrete cracks has also been completed based on concrete mixed crack's criterion.(3) Considering the influence to stability of concrete cracks by temperature change,the stress intensive factor of concrete cracks has been calculated under the maximum temperature rise condition and maximum temperature drop condition.The stability of cracks in concrete outside the spiral case has also been completed based on concrete mixed crack's criterion.(4) Using the non-linear spring element in ANSYS to simulate the bond-slip between reinforced and concrete,the FEM model with bond-slip has been established.The stress intensive factor of concrete cracks has been calculated and the stability analysis of concrete cracks has also been completed based on concrete mixed crack's criterion.During the modeling and calculating,the simulation of structure is as accurate as possible to reflect the characteristic of real engineering.As a result,some useful conclusions are drawn and can be referred to the real project.