| The accumulated elastic strain energy and deformation induced by the fault movement exceeds the strength of rock, and in sequence causes fault rupture and strata failure, and then earthquake occurs. Earthquake usually causes the instability of slope, endangering the safety of architectures. How to ensure the stability of rock slope on active fault zone is still a sophisticated problem needed to be solved urgently.Based on the investigation of engineering geological conditions of the rock slope of Xichong bridge at Yalu express way, a shaking table test was done to study the damage mechanism and failure mode of anti-dip rock slope under seismic condition. Additionally, 2D numerical modeling was employed to analyze the rock slope stability. At the end of paper, a supporting measure was put forward. Research contents and achievements were represented as follows:(1)According to the slip rate, distribution characteristics of active fault, the data of ground deformation and the historic record of earthquake, a conclusion was drawn that the east branch of An-ning River Fault and Tiezhaizi Fault have an important effect on the slope stability.(2)After detailed investigation of engineering geological condition of slope and elaborate description of slope rock structure, failure mode under natural condition is primarily estimated to be bending-fracturing-falling.(3)The model of the rock slope was made in the map scale 1:150 depending on the similarity theory, and a shaking table test was completed by means of this model on the six degree of freedom shaking table designed by CDUT. The experiment shows that the rock structure of physical scale model has loosed under earthquake with the deformation rate accelerated, the deformation range extended and the deformation degree increased; the evolution of a tensile crack is observed from the localization of joints at the slope surface; the front of slope collapses partly. According to the experiment, the loosed slope mass recesses within 55.6m from toe of slope to inside of slope horizontally, 45m from toe of slope to the top vertically; Deformation of the front of slope can reach 75cm, and fold-line fracture plane cuts the slope thoroughly and crops out at an elevation of 1340 meters.(4)To check the acceptability of the shaking table test, 2D numerical modeling was applied to study the deformation and damage of toppling rock slope under earthquake. In the process of numerical simulation, 9 monitoring points were distributed inside of the slope in order to monitor the displacement of the slope. The simulation result is as follows: the front of slope collapses and rock mass has partly loosed under earthquake; the maximum displacement, 61.6cm, is on the top; comparing the data of two experiments, it is found that two researching means lead to similar results. Besides, the displacement record of the monitoring points indicates that the displacement from the toe of slope to the top of the slope increases with the height; the displacement increases from inside to the outside of slope in the same horizontal level.(5)The result of physical simulation and numerical simulation illustrates that the deformation process is "loosing→toppling→falling of the rock mass" under earthquake within the shaking time; the thorough breakage leads to the instability of front of slope which ranges from EL. 1314m to EL.1340m.(6)In conclusion, the above mentioned experiments illustrate that instability of slope has obvious negative influence on the project. To cope with this problem, a supporting measures is designed as follows: firstly, slope is excavated with the ratio of 1:0.75, platform of 2m laying between them; secondly, anchor cables which are located with vertical and horizontal spacing of 4m in 5 rows with anchorage section of 3m, free section of 9.9m and anchorage angle of 20°are provided to protect and support the slope.
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