Upper limit analysis of seismic permanent displacement of near fault irregular inclined joint slopes based on the optimal reinforcement position of anti slip piles

In practical engineering, the slopes with inclined joints are mostly irregular in shape, and their geometric concavity and concavity characteristics have a significant impact on slope stability.Due to the influence of the concave convex characteristics of the slope surface, there is an optimal reinforcement position problem when using anti slip piles to reinforce the slope, and this problem becomes more prominent under short-term and high-energy near-fault pulse ground motions. Based on this, this article adopts the limit analysis upper limit method and Newmark permanent displacement method, Establish an energy consumption analysis model for permanent displacement of inclined joint slopes reinforced with anti slip piles on any irregular slope surface. The accuracy of the energy consumption model calculation results was verified by comparing the instability regions of three types of inclined joint slopes, namely straight, concave, and convex, through theoretical and numerical calculations. The research results indicate that:①The influence of slope geometric characteristics on slope stability is more dependent on the magnitude of slope line angle βi, followed by line height ai; ②As the cohesion cr and internal friction angle φr of the rock and soil increase, the influence of βi on slope stability gradually increases. With this proportional coefficient λ The increase in slope height H, the impact of βi on slope stability gradually decreases. The joint inclination angle is within the range of 10°~25°, convex slope is most sensitive to joint inclination angle; ③The permanent displacement of the slope generated by irregular slope inclined joints under strong pulse seismic motion is 32-35 times that of non pulse seismic motion; ④The optimal reinforcement position of anti slip piles on irregular inclined joint slopes under pulse seismic motion is more sensitive than that under non pulse seismic motion. The optimal reinforcement position for anti slip piles on convex and concave slopes is achieved in the upper and middle parts of the slope （xp/xl=0.6~0.7）. The optimal reinforcement position for anti slip piles on concave slope, convex slope, upper concave and lower convex slope, and straight slope is achieved in the upper middle part （xp/xl =0.5~0.6）, and as φr increases from 28°to 30°, the optimal reinforcement position moves towards the middle part （xp/xl=0.5）. The research results can provide theoretical support and guidance for the optimal reinforcement position of anti slip piles on non regular inclined joint slopes near-fault in similar engineering projects.