桩基低应变完整性测试的多次波分析

The Multi-reflected Wave Analysis on the Low Strain Integrity Testing of Pile Foundation

为了准确识别桩基低应变完整性测试中桩基缺陷的程度和深度,必须进一步研究速度信号中多次波的影响.利用反射波法成功地模拟出桩基动测中包含透射和多次反射波影响的速度曲线,可处理任意个不等距反射界面的情况,使得应力波在桩基中的传播规律有了进一步的认识;同时提出了相应的多次波反演新方法,可以反演包含透射和多次反射影响的速度波信号,该方法只需准确识别每次的第1个速度波,就可以准确识别桩基缺陷所对应界面的波阻抗变化规律及其对应深度.数值算例说明该方法是确实可行的.

In order to determine the exact pile faults and their corresponding depth on the low strain integrity testing of pile foundation,it is necessary to investigate the disturbance by the multi-reflected wave.The synthetic velocity wave in the integrity testing of pile is derived by the reflection method,considering the transmitted and the multi-reflected wave from no matter how many layers.So the behavior of the stress wave in the pile is clearer.Furthermore,the resulting new method to inverse the velocity wave is presented.When the every first exact wavelet can be determined,all the reflectance of the layers from the pile faults can be obtained.And the changes of the stress wave impedance and their depth are determined.The numerical examples show that the method is effective.