Four-dimensional lattice spring model for blasting vibration of tunnel surrounding rock

Four-dimensional lattice spring model (4D-LSM) has the intrinsic advantage of analyzing the large dynamic problem. It has better adaptability to the dynamic response of tunnel blasting excavation. The 4D-LSM model of the vibration in small-distance tunnel blasting is established. The dynamic response of the surrounding rock was analyzed by applying the nonreflective boundary condition and equivalent explosive load. The results show that the blasting vibration waves and the air pressure waves generated by tunnel blasting excavation are attenuated to the outside in the form of column surface wave. Due to the cavity effect of the blasting vibration, the vibration wave was reflected at the boundary of the neighboring tunnel contour. The peak particle velocity (PPV) of the rock sandwich area in the small clear-distance tunnel decreases with the increase in blasting distance. The blasting vibration wave was reflected by blasting cavity effect. It causes the increase in the peak particle velocity (PPV) of the surrounding rock mass in the local zone.