利用弯曲元测量土体表层剪切波速的初步试验

Preliminary tests of measuring shear wave velocity on soil surface using bender elements

土体剪切波速是土力学研究与岩土工程设计的关键参数之一。根据压电弯曲元波速测量的方向性,提出了侧向激发与接收的测量模式,使得弯曲元技术可用于室内和现场土体表层剪切波速的测量。在砂土模型内的初步试验表明,以激发元和接收元内侧间距为剪切波传播距离,并采用时域初达波法判别剪切波到达时间,则侧向激发与接收方式弯曲元的剪切波速测量结果准确可靠,精度与常规"对向激发与接收"方式相同。该弯曲元测试方法为当前大量涉及的取样扰动评价及地基处理质量控制等重要问题提供了便捷可靠的无损检测手段。

The shear wave velocity in soils was geotechnical engineering practices. A side-to-side the main parameter generally used in soil mechanics researches and type of source and receiver arrangement for bender element tests was proposed based on its plane directivity, and a new bender element system capable of measuring shear wave velocity on soil surfaces both in the laboratory and in the field was developed. It was shown by preliminary tests performed on sand model that, the travel distance of the proposed arrangement was taken as the distance between the inner edges of the elements, and the travel time of shear waves could be readily determined by the time domain first arrival method. The bender element tests with the side-to-side arrangement gave reliable measurement compared with that of the conventional tip-to-tip type, which offered a nondestructive tool for important themes such as assessment of soil disturbance and quality check of soil improvement.