关键词: 地震液化, 碎石桩复合地基, 减震作用, 振动台试验

Abstract: The soil liquefaction induced from earthquake and associated ground failure have been a major concern for geotechnical engineers in seismically-active regions. The harm of liquefaction and associated ground deformation can be controled using various ground-reinforcement methods; the macadam pile is the one that is commonly used. The effectiveness of macadam piles for the prevention of soil liquefaction during vibration period is often of three folds: densification, drainage and the reduction of the total cyclic shear stress in the soil. However, the design and evaluation methods remain focused on the densification of in-situ soils at present. In this study, the shaking table test is conducted to assess the effect of reducing the total cyclic shear stress in the soil for macadam piles as a liquefaction countermeasure. In a series of three separate model tests, the saturated sand is studied first without, then with stone columns. The effect of reducing the total cyclic shear stress is discussed based on the recorded dynamic responses and established theory model. The test and theoretical analysis results demonstrate that macadam piles can reduce the total cyclic shear stress in the liquefiable soil remarkably.

Key words: seismic liquefaction, composite foundation of macadam pile, decreasing vibration effect, shaking table test