侧装式弯曲元测量软黏土剪切波速的试验研究

发布时间：2018-04-08 12:22

本文选题：侧装式弯曲元　切入点：剪切波　出处：《岩土力学》2015年S1期

【摘要】：判断剪切波到达时间并计算相应的剪切波速是弯曲元试验的关键问题之一。受到试验仪器差异和研究者波速判断主观性的影响,很难客观地、准确地获得土体的剪切波速。针对该问题,提出采用侧装式弯曲元测试系统测量剪切波传播时间和土体的剪切波速,利用上海典型的淤泥质黏土进行试验,分别采用初达波法、特征值法和互相关法计算土体的剪切波速。试验结果表明,(1)初达波法在信号判定过程主观性较大,土体剪切波速受发射信号频率的影响明显;(2)采用第二峰值点(特征点法)得到的试验结果波动性较小;(3)在满足相似性的前提下,互相关法在一定频率范围内(20~30 k Hz)提高了确定剪切波速的客观性,降低了因试验者或激发频率的不同对试验结果产生较大影响的可能性。
[Abstract]:Determining the arrival time of shear wave and calculating the corresponding shear wave velocity is one of the key problems in bending element test.It is difficult to obtain the shear wave velocity of soil objectively and accurately under the influence of the difference of the test instrument and the subjective judgment of the wave velocity of the researcher.In order to solve this problem, a lateral bending element testing system is proposed to measure the propagation time of shear wave and the shear wave velocity of soil, and to use the typical silt clay in Shanghai to carry out the test, respectively, using the initial arrival wave method.The shear wave velocity of soil is calculated by eigenvalue method and cross correlation method.The experimental results show that the initial arrival wave method is more subjective in the process of signal determination.The shear wave velocity of the soil is obviously affected by the frequency of the emission signal. (2) the test results obtained by the second peak point (characteristic point method) are less volatile than those obtained by the method of characteristic points), under the premise of satisfying the similarity, the shear wave velocity of the soil is obviously affected by the frequency of the emission signal.The cross-correlation method improves the objectivity of determining the shear wave velocity in a certain frequency range of 2030kHz, and reduces the possibility that the test results will be greatly affected by the difference of the experimenter or the excitation frequency.
【作者单位】：华东建筑设计研究院有限公司地基基础与地下工程设计研究中心;上海基坑工程环境安全控制工程技术研究中心;
【分类号】：TU442

【共引文献】