冻土纵、横波复合宽带超声换能器系列研制

Development of Broadband Ultrasonic Transducers for Frozen Soil Tests

根据冻土弹性波测试的要求 ,本文研制成功一种冻土测试用 2 5 0kHz、5 0 0kHz和 1MHz系列的纵波、横波复合宽带超声换能器 .这种换能器具有灵敏度高、频带宽、声阻抗低的特点 ,适于冻土力学特性测试 .作者介绍了它的结构及相应系统特性 ,并以1 0ps的延时时间精度 ,在零度以下气温条件下 ,实测了不同含水量 ( 7%、1 0 %、1 6 %、2 2 %和 2 5 % )及负温 ( - 2℃、- 4℃、- 6℃、- 8℃、- 1 0℃、- 1 2℃、- 1 4℃、- 1 6℃、- 1 8℃和 - 2 0℃ )冻结兰州黄土试块的纵、横波速 ,获得了较好的结果 .

A series of broadband ultrasonic transducers are developed, which has the advantage of high sensitivity,wide frequency band and lower sonic impedance, and suitable for use in frozen soil test to measure the longitudinal and transverse waves in frozen soil. The structure and system characteristics of the transducers are described. An experiment for measuring the longitudinal and transverse wave velocities in Lanzhou loess with different moisure contents and under different minus temperatures is reported. The measuring precision in the experiment is up to 10ps.