The coupling effects of rainfall, earthquake, and complex topographic and geological conditions complicate the dynamic responses and disasters of slope-tunnel systems. For this, the large-scale shaking table tests were carried out to explore the dynamic responses of steep bedding slope-tunnel system under the coupling effect of rainfall and earthquake. Results show that the slope surface and elevation amplification effect exhibit pronounced nonlinear change caused by the tunnel and weak interlayers. When seismic wave propagates to tunnels, the weak interlayers and rock intersecting areas present complex wave field distribution characteristics. The dynamic responses of the slope are influenced by the frequency, amplitude, and direction of seismic waves. The acceleration amplification coefficient initially rises and then falls as increasing seismic frequency, peaking at 20 Hz. Additionally, the seismic damage process of slope is categorized into elastic (2-3 m/s2), elastoplastic (4-5 m/s2) and plastic damage stages (>= 6.5 m/s2). In elastic stage, MPGA (ratio of acceleration amplification factor) increases with increasing seismic intensity, without obvious strain distribution change. In plastic stage, MPGA begins to gradually plummet, and the strain is mainly distributed in the damaged area. The modes of seismic damage in the slope-tunnel system are mainly of tensile failure of the weak interlayer, cracking failure of tunnel lining, formation of persistent cracks on the slope crest and waist, development and outward shearing of the sliding mass, and buckling failure at the slope foot under extrusion of the upper rock body. This study can serve as a reference for predicting the failure modes of tunnel-slope system in strong seismic regions. (c) 2025 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/ 4.0/).

With more and more the transportation tunnels that have been and will be constructed in loess areas in Northwest China with high earthquake potential, the overall stability of tunnel portal sections under earthquake action and the related aseismic countermeasures has attracted the attention of both scholars and engineers, especially for tunnels in upper slope connecting high bridges crossing rivers or valleys. To study the dynamic response characteristics and damage evolution of steep loess slopes with tunnels under earthquake action, large-scale shaking table tests and numerical simulations were performed on steep loess slopes with tunnels. In particular, three-dimensional noncontact optical measurement techniques were used to obtain the slope surface displacements. The results showed that the main deformation patterns of the studied slopes were horizontal movement and settlement when the seismic waves were input in the X and X-Z directions, respectively. However, the seismic wave from the X direction had a greater impact on the deformation of a slope than that from the X-Z direction, and the tunnel portal slopes were ultimately destroyed under the action of a large horizontal seismic acceleration. Slope failure ahead of a tunnel was divided into four stages, i.e., the elastic deformation stage, plastic deformation accumulation stage, local failure stage, and overall failure stage. The existence of the tunnel had a great influence on the peak ground acceleration (PGA) and the PGA amplification factor (PGAAF) of the surrounding soil mass. The changes in the PGD and PGA on the slope surface determined via numerical simulation were basically consistent with the experimental results.