Permanent displacement limit analysis of jointed rock slope under the near-fault pulse-like ground motion based on the rotational - translational combined failure model and tensile strength cutoff

As an increasing number of major projects are being planned and constructed in near-fault regions, the issue of slope failure induced by near-fault ground motion has emerged as a focal concern, representing a secondary disaster resulting from earthquakes. In practical engineering, due to the controlling effect of joint surfaces, the translational (TM) and rotational (RM) failure models, as well as the upper rotational-lower translational failure model (URLTM), are prone to occur in rock slopes. In addition, the near-fault ground motion, characterized by short-duration and high-energy pulse-like ground motions (PLGM), amplifies the tension characteristics of back edge cracks, increasing the risk of slope failure. Based on this, this study particularly focuses on exploring the dominant control and contribution of strong PLGM to permanent displacement. Through comparative analysis, the accuracy and reliability of these models are assessed. Based on the URLTM, k c is influenced by both fi and S. As S gradually approaches fi, k c first decreases and then increases. When fi is relatively large, k c increases linearly with the values of S / fi and S. Based on IURLTM, as the tension correction coefficient (mu) increases, D f decreases significantly. When considering vertical ground motion, as the proportional coefficient (A) increases, D f decreases, and the shape of the sliding surface of the upper rotation failure becomes more curved. Notably, strong near-field PLGM induces 25 -35 times greater permanent displacement than far -field non-PLGM, with pulse waves contributing more than 50% to the overall displacement. This study underscores the critical need to consider the controlling effect and contribution degree of near-fault PLGM on the stability of jointed rock slopes, particularly in near-fault regions.