A new integrated experimental and theoretical framework to simultaneously measure mechanical, hydraulic and high frequency dielectric properties of soil during shrinkage was designed aiming at the development, verification and validation of constitutive electromagnetic material relationships. The electromagnetic response of a soil to a high frequency (radio to microwave) signal contains information that can be harvested to characterise soil including its state variables such as water content, density and soil suction. The developed framework allows decoding of this response. In the presented study on kaolin (i) shrinkage tests ii) shrinkage tests with non-destructive determination of dielectric spectra from 50 MHz to 3 GHz, and (iii) determination of the soil suction relationship over a broad range of water content, have been performed. The results of this investigation show a nonlinear evolution of the permittivity at 1 GHz as a function of water content with a sharp transition. None of the advanced mixture approaches that were applied in a forward approach could quantitatively characterize this relationship between the permittivity and the volumetric water content. With a recently developed advanced mixture equation (Augmented Broadband Complex dielectric Mixture model – ABCM) applied in an inverse scheme, the saturated part of the shrinkage curve was able to be estimated from the permittivity measurements. A quantitative relationship between the cementation exponent within this mixture equation and the soil suction have also been established. The conditions and reasons for the drop in permittivity remains subject of future research.

设计了一种新的综合实验和理论框架，用于同时测量收缩过程中土壤的机械、水力和高频介电特性，旨在开发、验证和验证本构电磁材料关系。土壤对高频（无线电到微波）信号的电磁响应包含可以收集来表征土壤的信息，包括其状态变量，如含水量、密度和土壤吸力。开发的框架允许解码此响应。在所介绍的高岭土研究中，(i) 收缩试验 ii) 无损测定 50 MHz 至 3 GHz 介电谱的收缩试验，以及 (iii) 测定大范围含水量范围内的土壤吸力关系。执行。这项调查的结果表明，1 GHz 下的介电常数随含水量的变化呈非线性演变，并具有急剧转变。在前向方法中应用的高级混合方法都不能定量表征介电常数和体积含水量之间的这种关系。通过在逆方案中应用最近开发的高级混合方程（增强宽带复合介电混合模型 - ABCM），能够从介电常数测量中估计收缩曲线的饱和部分。还建立了该混合物方程中胶结指数与土壤吸力之间的定量关系。介电常数下降的条件和原因仍然是未来研究的主题。