软件滤波在土体自振柱试验中的应用

Application of Software Filter in the Free Vibration Column Test of Soils

自振柱试验是测量土样动剪切模量和阻尼比的常用方法,但由于噪声等环境因素的影响,土样扭剪自由振动的衰减波曲线有时会因高频干扰出现不平滑现象,难以得到合理的测试结果。软件数字滤波是解决这类问题的有效方法。本文通过多种软件数字滤波方法优缺点的对比,认为平均滤波法和惯性滤波法能有效解决试验数据中的高频干扰问题,并分别选择适当的滤波参数,得到了平滑的自振衰减波曲线;最后,采用平均滤波法处理了两组自振柱试验数据。结果表明,软件滤波法确能有效消除不合理数据,得到符合一般规律的土体动剪切模量和阻尼比试验结果,从而验证了其在土体自振柱试验中的应用价值。

Free vibration column test is a common and damping ratio of soil specimen. Because of the testing method for measuring dynamic shear modulus influence of environmental factors, such as noises etc, the free vibration attenuation wave curve of soil specimen obtained from the test sometimes may be unsmooth, which leads to incorrect dynamic shear modulus and damping ratio. Software digital filter is an effective method to solve this problem. By comparing with the main advantages and disadvantages of many filters, the average method filter and the inertia method filter can be adopted to solve this problem more effectively for this problem. Suitable parameters of the two filters are chose to obtain smoothing curves of free-vibration attenuation wave. At last, three groups of experimental data are selected to discuss the effectiveness using the average method filter. The result shows that it can eliminate the abnormal results due to high-frequency interfering wave effectively, and thus the desirable results of dynamic shear modulus and damping ratio can be obtained. This result verified the application value of software filter in free vibration column test.