动弹模量阻尼比测试技术与归一化特性研究

动弹模量与阻尼比是土动力分析最基本的力学参数,一般通过较小应变范围的动三轴试验得到,测试技术的可靠性与试验参数求取的准确性是进行抗震安全性评估的关键。通过室内动三轴试验,比较了力与位移传感器内置与外置、不同相对位置等因素对滞回圈、动弹模量与阻尼比的影响,提出了针对存在残余变形的不闭合滞回圈的动弹模量与阻尼比的计算方法,比较了频率、围压、固结比等因素对试验成果的影响规律及特征,并在Janbu公式中引入固结比的幂函数影响因子,对不同围压、不同固结比下的动弹模量阻尼比进行了归一化特性研究。研究成果有利于提高国内科研机构在土动力参数测试方面的能力,对抗震工程与科研有积极的参考价值。

Test technology and normalized characteristics of dynamic elastic modulus and damping ratio

Dynamic elastic modulus and damping ratio are the basic mechanical parameters for dynamic analysis of soils, which can be usually got by dynamic triaxial tests with small strain range. The reliability of test technology and the accuracy of the test parameters are the key to the aseismic safety assessment. Based on the results of the dynamic triaxial tests, the influences of several factors such as using internal or external sensors, relative position of force and displacement sensors on the hysteresis loop, dynamic elastic modulus and damping ratio are analyzed. A new method is proposed, which can be used to calculate the dynamic modulus and damping ratio when there is non-closed hysteresis loop of residual deformation, and the influence laws of the frequency, confining pressure, consolidation ratio and other factors on the test results and their characteristics are compared. The influence factor of power function is also added to the Janbu formula, and the normalized characteristics of dynamic elastic modulus and damping ratio with different confining pressures and consolidation ratios are studied. The research results will help improve the ability of domestic research institutions to test the dynamic parameters of soils, and this study also has a positive reference significance to the antiseismic engineering and scientific research.