地基阻尼比测试的一种计算方法

基于规范1－2]，对某动力基础阻尼比进行了测试及计算。数值处理结果表明，在自由振动和强迫激励作用下，阻尼比测试数值与弹性半空间近似公式及规范推荐近似公式的结果存在较大差别。为此提出了利用基础表面若干测点的3向振动时程合成基础质心6自由度时程，并以该时程曲线作为地基动力参数的测试依据。在此基础上，建议相关规范应推荐在某些重要基础建造时，在基础底面适当位置预埋传感器，以基础底面振动测试数据作为地基阻尼比等动力参数的计算依据更为准确。

A subsoil damping ratio testing and data processing method

Damping ratio testing method of a foundation was studied theoretically and experimentally based on the corresponding Chinese measurement and design codes. It is shown that there is a relatively large difference between numerical results of codes and approximate formulae based on elastic half-space analytical solution. Therefore, six-degree-freedom time histories of the center of mass center of a foundation are calculated from three-component vibration curves of some points on the foundation surface to be selected as the analytical time-history of some dynamic parameters such as compressive stiffness, rotational stiffness, shearing stiffness, torsional stiffness, damping ratio and mass of vibration of subsoil. It is recommended that the vibration sensors should be pre-embedded in some proper positions of the foundation bottom surface to improve the precision of subsoil dynamic parameters measurement.