关键词: 软弱夹层, 振动台试验, 加速度放大系数, 动力响应, 影响因素分析

Abstract: Based on similarity theory, two models of rock slope with different thicknesses of horizontal weak interlayers are maded. The sizes of slope models are: 1.80 m in height, 1.65 m in length, 1.50 m in breadth, and the slope angel is about 60°, the thicknesses of weak interlayers are 3 cm and 15 cm, respectively. Using the recorded data of sensors in the large-scale shaking table test and orthogonal design, the acceleration dynamic response characteristics of slope and influencing factors are investigated with different input wave kinds, excitation directions, frequencies and amplitudes. The results show that the dynamic acceleration amplification coefficients in the slope body increase with increasing elevation, and the amplification coefficients show nonlinearly surface effect. The horizontal amplification coefficients along slope surface increase with the increase of elevation in the form of fluctuation, especially at the middle and upper part of the slope with thin interlayer. The vertical amplification coefficients differ owing to the thickness of weak interlayer, it decreases in the local part of slope with thin interlayer and then increase to the maximum at the shoulder, but it appears at the bottom of interlayer for the slope with thick interlayer. Under the equal input seismic load, the vertical amplification coefficients are 0.75 times the horizontal amplification coefficients in the interior of slope body. On the surface of slopes, the magnitude of amplification coefficients in both horizontal and vertical directions are concerned with the elevation. Under the weak interlayer, the vertical amplification coefficients are greater than the horizontal’s, whereas above the weak interlayer, the result is reverse. The effect of weak interlayer on dynamic response of slopes also varies with the different excitation directions. The dynamic responses are amplified in horizontal direction, but it is weakened in the vertical direction. In order of importance, the factors influenting dynamic response of solpe is in turn: elevation, position of slope, thickness of weak interlayer, amplitude, wave types and excitation direction. Among the selected influencing factors, the elevation, position of slope and thickness of weak interlayer can significantly influence acceleration dynamic response of slopes.

Key words: weak interlayer, shaking table test, acceleration amplification coefficients, dynamic response, analysis of influencing factors