冻土纵、横波宽带超声换能器的研制

Developing of a Broadband Ultrasonic Transducer for Frozen Soils

根据冻土弹性波测试的要求，研制了一种冻土测试用的 ５００ ｋＨｚ纵波、横波复合宽带超声换能器，其性能具有灵敏度高、频带宽、声阻抗低的特点，适用于冻土力学特性的测试．文章介绍了它的结构及相应系统特性，并以１０ｐｓ的延时时间精度，在零度以下气温条件下，实测了不同含水量及负温冻结兰州黄土试块的纵、横波速，获得了好的结果．

The authors have developed succeedly a kind of 500 kHz 1- 3 composite broadband ultrasonic transducer used for measuring longitudinal wave and transverse wave in frozen soils. The ultrasonic transducer has the characteristics of highest sensitivity, wide frenquency-band and lower sonic impedance. It is suitable for measuring mechanical properties of frozen soils. The configuration, the corresponding characteristics and testing results are presented in this paper. The longitudinal wave and transverse wave velocities of frozen Lanzhou leoss are measured under various water contents (7% — 25 %) and temperatures (-2— -20℃ ) using this system, and the measuring precision is within 10 ps.