The Experimental Study Of The Fracture Criterion And Dimensional Effect For Gravity Dam Heel On Bedrock

The cracking problem of concrete dam heel on bedrock is a subject closely related to hydro-dam design. This paper provides experimental study of the fracture criterion and dimensional effect on gravity dam heel zone on bedrock through model test.The stress expression for different elastic ratio V-notch is extrapolated in this paper by using complex variable function and the characteristic equations satisfying with boundary conditions are obtained. At the same time, the nonlinear equations are solved by the Newton iterative method, and the characteristic roots are obtained under different ratio of elasticity modulus of bedrock and concrete. The stress and displacement expression for gravity dam heel zone is obtained. The stress expression shows that the stress at dam heel zone has singularity.The factors of stress intensity of different elastic ratio V-notch are defined. The dimensionless stress intensity factor of test specimen is calculated by using meshless method.Seven dam type specimens under different stress states are chosen based on the calculation results of more than thirty stress combination of the specimens. The stress intensity factors (K_â… ,K_â…¡) of these dam specimens in dam heel zone have different rates.Above specimens are used in the study on fracture criterion about incipient fracture criterion for contact surface of rock and concrete in dam heel zone. Toughness of incipient fracture for contact surface of dam type specimens has been measured to obtain the critical fracture curves and the empirical formula. The empirical formula is expressed as: The dam specimens of different scales are used in the study of the dimensional effect on dimensionless factors of stress intensity and fracture toughness.These results can be applied to analyze incipient fracture in gravity dam heel zone.