A Study On Shear Fracture Process And Fracture Toughness Of Joint-grouting In Concrete Dam

To assess the quality and the stability of the grouting construction of dam joints, it is necessary to investigate the property of the mode II fracture and measure the mode II fracture toughness. The paper mainly studies the effect on mode II fracture process and mode II fracture toughness K_(?)c of joint-grouting in concrete dam of highness, width, relative crack lenghth and fiber content. Because of the difficulty in determination of the critical mode II cracking load which was used to ascertain the mode II fracture toughness K_(?)c, the electric property of the joint-grouting material was applied to investigate mode II fracture of double-edge specimen. The main conclusions are as follows.(1) The double-edge mode II specimens allows pure mode II fracture and it is possible to determine mode II fracture toughness K_(?)c of joint-grouting material.(2) The experimental results also show that electric resistance increases with the increase of the measured load and displacement and the behavior of electric resistance of joint-grouting material can be used to determinate the critical mode II fracture load which is a basis to ascertain K_(?)c values of the joint-grouting material using the double-edge specimen.(3) The K_(?)c of the joint-grouting material is depended on the specimen highness and width. The .K_(?)c increases monotonically as the specimen highness or width degreases.(4) The K_(?)c of the joint-grouting material is independent of ligament length and fiber content.