Provided the results of a research conducted to investigate the relationships between the empirical vibration attenuation equation of Peak Particle Velocity （PPV） and the Scaled Charge （SC） through testing the blasting-induced vibrations on the spot of Wanshishan tunnel based on 96 vibration recordings. It is found that the maximum charge amount per delay in Wanshishan tunnel excavating is determined by the buildings on the surface and the constructed tunnel nearby. Considering that the repeated blast loading in tunnel blasting caused accumulative effects of damage on buildings, comfortable threshold damage limits of PPV to maintain buildings safety was given. Dynamic Stress Ratio （DSR） was adopted to study the stability of constructed tunnel on the action of blasting induced vibrations. The method to determine specific maximum charge amount per delay in Wanshishan tunnel excavation was given. It is proved that the findings in this study are very effective to control the negative effects of blasting-induced vibrations on buildings on the surface and constructed tunnel nearby.
By considering the effect of hydraulic pressure filled in wing crack and the connected part of main crack on the stress intensity factor at wing crack tip, a new wing crack model exerted by hydraulic pressure and far field stresses was proposed. By introducing the equivalent crack length lcq of wing crack, two terms make up the stress intensity factor K1 at wing crack tip： one is the component K（1） for a single isolated straight wing crack of length 2l subjected to hydraulic pressure in wing crack and far field stresses, and the other is the component K1^（2） due to the effective shear stress induced by the presence of the equivalent main crack. The FEM model of wing crack propagation subjected to hydraulic pressure and far field stresses was also established according to different side pressure coefficients and hydraulic pressures in crack. The result shows that a good agreement is found between theoretical model of wing crack proposed and finite element method （FEM）. In theory, an unstable crack propagation is shown if there is high hydraulic pressure and lateral tension. The wing crack model proposed can provide references for studying on hydraulic fracturing in rock masses.
