Experiment And Numerical Analysis For Fracture Character Of RCC Crack Director

The construction technique using RCC (Roller Compacted Concrete) in dam engineering , with simple process , high intensity on the dam , short duration , low cost , adaptability , and other characteristics , has become one of the most competitive dams and has been used and developed widely in China . Integrating our RCC technique , RCC in mixture proportion design has formed the characteristics of a small amount of cement and high fly ash . However , it is because the large number of fly ash are incorporated , the distribution time of heat of hydration become slow, at the same time increasing ascent speed of RCC also results in thermal stress increasing , so the dam is destructed . Currently setting crack director is the more mature measure , that is to say , crack director on the dam enlarges its own tensile stress to give priority to crack . Therefore , the crack director test and numerical simulation analysis are paid attention more and more by professionals .The development status of the construction technique using RCC in dam engineering was described first . According to summarizing the thermal stress and temperature control measures , cracks problem and control measures causing by thermal stress were analyzed and several methods of controlling cracks in the structure were discussed . Crack in RCC arch dam is mainly generated by the temperature stress, setting crack director can dissipate dam stress and control the development direction of crack, thus ensuring the integrity of the dam. Combining with the National Natural Science Foundation project《Equivalent Strength for Crack Director t of High RCC Dam and Study of Optimal Layout》, the axial tension test of unidirectional interval crack directors'and bilateral interval crack directors'specimens were done , and the relationships between equivalent strength for crack director and the number of induced film and weaken degree were obtained , then the fracture analysis of RCC was conducted through the load-displacement and load-strain curves.The different types of axial tension specimens were simulated and the obtained experimental datas were analyzed to verify superiority of the non-penetrating crack director . According to the development of strain around crack director , combing with the stress contours , the damaging process of crack director was judged and the effective layout of crack director was proposed , which make the test of equivalent strength for RCC crack director more complete .The conclusions of the trial can be as designing basis for crack director in practical engineering , test simulations can provide reference for researching similar test of equivalent strength for RCC crack director in the future .