Compared with far-field ground motion, the most significant feature of near-fault pulse-like ground motion is the long-period, large-scale velocity pulse. This paper proves through statistical analysis that near-fault pulse-like ground motion is an important cause of slope damage and landslide. And use numerical simulation software FLAC3D to establish a homogeneous rock slope model, select near-fault ground motions with velocity pulses and non-pulse near-fault ground motions, and use an improved energy method to identify and extract the selected near-fault ground motions. The dynamic response of the slope under the action of near-fault ground motions with and without velocity pulses is comparatively studied, and the dynamic response law of the slope under the original records, pulse records, and residual records of pulse-like ground motions is explored. The research results show that the near-fault ground motions with velocity pulses can cause a greater dynamic response than ground motions without velocity pulses. There is an elevation magnification effect in the PGA distribution of the slope horizontally. The shorter-duration pulse record can cause a larger dynamic response, and the PGA magnification factor under the effect of the residual record is smaller than the original record. The velocity pulse strengthens the earthquake damage to the slope, and the slope produces a stronger dynamic response.
The near-fault ground motion is different from the far-field ground motion. Researchers began to understand the near-fault pulsed ground motion in the last century. Infield investigation, it was found that the structure near the fault often suffered more serious damage. Housner et al. (1958) studied the seismic records of Port Hueneme in the United States. This is the first time that a single-pulse strong seismic record has been recorded. Through analysis, it is found that almost all the energy in the earthquake is concentrated in one pulse, which is believed to be the main reason for the serious damage to the structure. Bolt et al. (1971) analyzed the San Fernando seismic records in the United States, and the results showed that the near-fault pulsed ground motion would cause more serious damage to the structure compared with the ordinary ground motion. Bertero et al. (1978) reviewed and studied the existing near-fault ground motion and pointed out the main characteristics of high-amplitude and long-period acceleration pulse near-fault ground motion, which would cause devastating damage to buildings. After realizing the great destructivity of near-fault ground motion, a large number of scholars began to conduct in-depth research on the characteristics of such ground motion. Somerville et al. (1993;1997) studied the effects of the directional effect of rupture on the duration and amplitude of ground motion and found that the propagation velocity and direction of fault rupture jointly affect the velocity pulse. In addition, medium and long-period structures are more vulnerable to damage under the action of near-fault pulse ground motion. Bray et al. (2004) studied near-fault ground motions with forwarding directionality and proposed an empirical relationship between PGV and velocity pulse period. It is believed that the energy of ground motion is mainly concentrated in a narrow period band centered on the pulse period.