关键词: 土工测试, 加速度时程, 积分位移, 数据分析方法, 振动台试验, 可靠性

Abstract: Measurement on strain deformation of soils is one of the significant challenge in geotechnical testing technology. Double integration of acceleration measurement for displacement is a common method in understanding the shear strain response of soil in in-situ monitoring and model tests under dynamic loading, but it lacks validity and reliability study. In this paper, the sand-slope-rocker-mass vibration table model test was designed, besides the mass acceleration and time-history response of displacement under multiple working conditions and two seismic loads were measured. Four representative methods were applied to solve dynamic and permanent displacement and their reliability and deflection effects were discussed. The results show that high-pass filtering method, which is less affected by the integral methods, is reliable to obtain dynamic displacements. Comparing the integral displacement with the measurement values in different dynamic displacement conditions under two earthquake loadings, the average errors of peak values are less than 25%. However, the dynamic displacements calculated by double integration present obvious deviation, which is related to the function form and processing flow. To obtain permanent displacements, the integral methods consisting of high-pass filtering process are invalidated due to the loss in low frequency components of acceleration records. The permanent displacements calculated by double integration method are in good agreement with the measured values. The relative errors are 7% and 5% respectively under two seismic loading conditions. The base deflection presents less impact on the reliability of dynamic displacements in different integral methods. But it plays obvious impacts on the permanent displacements. The permanent displacements calculated by double integration are distorted induced by the influence of base deflection. Experimental methods and conclusions herein provide valuable scientific reference and useful suggestions in the selection of double integral methods of acceleration to obtain soil displacement .

Key words: geotechnical testing, acceleration time history, integral displacement, data analysis methods, shaking table tests, reliability