Determination of the Small-Strain Stiffness of Hard Soils by Means of Bender Elements and Accelerometers
Determination of the Small-Strain Stiffness of Hard Soils by Means of Bender Elements and Accelerometers
复制标题
利用弯曲元件和加速度计测定硬土的小应变刚度
DOI：
10.1007/s10706-013-9678-7
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发表时间：
2014
影响因子：
1.7
通讯作者：
A. Gomes Correia
中科院分区：
文献类型：
--
作者：
C. Ferreira;J. Martins;A. Gomes Correia
在实验室中直接测定地震波速度已成为世界范围内的普遍做法，因为它在定义非常小应变下的刚度方面具有很大的潜力。用于地震波测量的技术之一利用压电换能器，诸如弯曲元件（BE）。然而，这种技术的适用性仍然存在一些限制，即对于刚性地质材料，如压实土壤，天然或人工胶结土壤和软或弱岩石。为了克服这个问题，两个加速度计已经与BE结合使用。在本文中，将详细介绍在应力路径三轴室上实施的这种组合试验装置。将提出一个应用研究的硬土，准备通过实验室压实和三轴压缩在不同的各向同性应力水平的测试。本文还将介绍仪器、程序和解释分析。这种设置的优点有两个方面：（1）加速度测量结果的解释是直接的，因为信号具有相同的性质;（2）这些测量结果可用于验证BE信号，从而最大限度地减少BE结果解释的主观性。此外，加速度计可以在BE的解释变得过于复杂的地方自主使用。这项研究的结果，使验证用于BE测试的解释方法。此外，这种传感器的组合设置提供了一种简单而强大的工具，用于消除BE测试固有的主观性，从而能够可靠地测量各种材料的小应变刚度。
AbstractDirect determination of seismic wave velocities in the laboratory is becoming common practice worldwide, given its great potential in the definition of the stiffness at very small strains. One of the techniques for seismic wave measurement makes use of piezoelectric transducers, such as bender elements (BE). However, some limitations remain to the applicability of this technique, namely for stiff geomaterials, such as compacted soils, naturally or artificially cemented soils and soft or weak rocks. To overcome this issue, two accelerometers have been used in conjunction with BE. In the present paper, this combined test setup implemented on a stress-path triaxial chamber will be detailed. An application study will be presented for a hard soil, prepared by laboratory compaction and tested in triaxial compression at different isotropic stress levels. The equipments, procedures and interpretation analyses will also be described. The advantages of this setup are twofold: (1) the interpretation of the acceleration measurements is straightforward, since the signals are of the same nature; (2) these measurements can be used to verify the BE signals, and thus minimize the subjectivity of the interpretation of BE results. Additionally, the accelerometers can be used autonomously wherever the interpretation of BE becomes too complex. The results of this research enabled to validate the interpretation methods used for BE testing. Moreover, this combined setup of transducers provided a simple yet powerful tool for eliminating the subjectivity inherent to BE testing, enabling reliable measurements of small-strain stiffness for a wide range of materials.