Abstract This paper describes a recently developed technique of evaluating elastic properties of geomaterials in the large size triaxial apparatus enabling to propagate elastic waves even in coarse-grained geomaterials. A flat surface transducer of 80 mm in diameter has been developed embedding four pairs of compressional and shear wave measuring piezoceramic elements. The assemblage of piezoceramics, interpretation of results, verification of performance and applicability are corroborated. It has been shown that an accumulated strength of numerous piezoceramics in form of a single transducer significantly improved the integrity of the transducer enabling to evaluate elastic wave velocity in a large size the triaxial specimen of 230 mm × 230 mm × 500 mm. An investigation on three sorts of granular materials; fine, (d50 = 0.2 mm), medium, (d50 = 1.7 mm) and coarse, (d50 = 12 mm) is carried out. Small strain stiffness of tested geomaterials is evaluated by newly developed large-size disk transducer method and small-strain cyclic loadings. Stiffness measured by both static and elastic wave measurement is confirmed to be followed similar trends. The large size disk transducer evinces the competent performance showing the stiffness evaluated by this method scattered within 20% of the stiffness achieved by a static method and compared with available previous researches as well.

中文翻译：

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升级圆盘换能器测量粗粒颗粒材料弹性波的发展与性能启示

摘要 本文描述了一种最近开发的评估大尺寸三轴装置中地质材料弹性特性的技术，即使在粗粒地质材料中也能传播弹性波。已开发出直径为 80 毫米的平面换能器，嵌入了四对压缩和横波测量压电陶瓷元件。压电陶瓷的组合、结果的解释、性能和适用性的验证都得到了证实。已经表明，单个换能器形式的众多压电陶瓷的累积强度显着提高了换能器的完整性，从而能够评估大尺寸 230 mm × 230 mm × 500 mm 三轴试样的弹性波速度。三种颗粒材料的研究 精细，（d50 = 0.2 毫米），中等，（d50 = 1。7 毫米）和粗，（d50 = 12 毫米）进行。通过新开发的大尺寸圆盘换能器方法和小应变循环加载来评估被测土工材料的小应变刚度。通过静态和弹性波测量测量的刚度被证实遵循类似的趋势。大尺寸盘式换能器表现出良好的性能，表明通过这种方法评估的刚度分散在静态方法获得的刚度的 20% 内，并与可用的先前研究进行了比较。