Bulk density and soil stiffness moduli are vital physical parameters related to soil compaction, porosity, moisture storage capacity, soil penetration resistance and structural integrity. Conventional methods for measuring soil density and stiffness moduli are destructive, time-consuming, complex, expensive and often require skilled operators to conduct the tests. A new soil density and stiffness moduli measurement technique that can evaluate soil density and stiffness moduli more rapidly, efficiently and precisely, at a low cost is introduced here. This study evaluated the use of shear wave velocity measurements using the piezoelectric extender and bender elements as a viable alternative to measure soil density and stiffness moduli of soil. To test this idea, soda-lime glass beads of <0.002, 0.04–0.07 and 1.00–1.30 mm in diameter were used to develop the empirical relationship between the shear wave velocity and the bulk density of soil in laboratory conditions. These empirical equations were then tested on sands and clayey soils for validation. Accuracy in terms of coefficient of determination (R2) and root mean squared error (RMSE) from the current and existing studies ranged within 0.91–0.93 and 0.073–0.177 g cm–3 respectively. Both shear and Young moduli were compared with the shear wave velocity of soil, with R2 and RMSE of 0.96–0.97 and 0.48–3.5 MPa respectively. The major advantage of this technique is that input and output signal data can be stored in a computer that can be used to calculate soil density and stiffness moduli automatically. This technique could play a vital role in improving crop yield and soil management practices.

中文翻译：

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使用压电传感器根据剪切波速度测量土壤容重

容重和土壤刚度模量是与土壤压实、孔隙度、水分储存能力、土壤渗透阻力和结构完整性相关的重要物理参数。测量土壤密度和刚度模量的传统方法具有破坏性、耗时、复杂、昂贵，并且通常需要熟练的操作员进行测试。本文介绍了一种新的土壤密度和刚度模量测量技术，可以更快速、有效和精确地以低成本评估土壤密度和刚度模量。本研究评估了使用压电扩展器和弯曲器元件作为测量土壤密度和土壤刚度模量的可行替代方案的剪切波速度测量的使用。为了测试这个想法，使用 <0.002、0.04–0.07 和 1.00–1 的钠钙玻璃珠。30 毫米直径被用来开发剪切波速度和实验室条件下土壤容重之间的经验关系。然后在沙子和粘土上测试这些经验方程以进行验证。当前和现有研究的决定系数 (R2) 和均方根误差 (RMSE) 的准确度分别在 0.91–0.93 和 0.073–0.177 g cm–3 范围内。剪切模量和杨氏模量都与土壤的剪切波速度进行了比较，R2 和 RMSE 分别为 0.96-0.97 和 0.48-3.5 MPa。这种技术的主要优点是输入和输出信号数据可以存储在计算机中，可用于自动计算土壤密度和刚度模量。该技术可以在提高作物产量和土壤管理实践方面发挥重要作用。