中文摘要：

直接量测基础冲刷深度比较困难，通过桩基振动频率推测冲刷深度是一种可行的方法。采用瞬态激发方式使埋在土中的单桩产生振动，分别利用固定在桩头和埋入土中的加速度传感器记录振动信号。通过改变单桩整体埋深来模拟整体冲刷，在桩周放坡开挖模拟局部冲刷，测试单桩的振动频率，初步得到单桩自振频率随冲刷深度和冲刷形态变化的规律。试验研究表明，单桩自振频率随冲刷深度增加而降低，整体冲刷对单桩自振频率的影响略大于局部冲刷。

英文摘要：

The scour depth under the waterlevel for bridge piles is difficult to be detected directly. It may be possible ato estimate the scour depth of a single pile through the relations between scouring depth and natural vibration frequency. Single pile vibration was excited by transient excitation and acceleration sensors fixed on pile head and in soil recorded responses. General scour depth was simulated by changing the embedded depth of single pile and the local scour depth is simulated by excavating around the pile step by step. Natural vibration frequencies of the pile were obtained from the data. The relationship between embeded depth and natural vibration frequency was established, which can be used as a reference value for further research. The tests showed that natural frequencies of the single pile reduce with the scour depth increasing ; and the general scour affect the natural frequency of single pile greater than the local scour.