In the case where a heat-pulse (HP) sensor installed in a layered soil with the heating and sensing probes positioned at different layers, the HP measurement violates the underlying assumption of soil homogeneity for the cylindrical perfect conductors (CPC) theory that is used to interpret the HP data. In this study, laboratory and numerical studies were performed to evaluate the heat transfer patterns and models to analyze HP measurement data when heating probe was positioned at the interface of a double-layered soil with different upper- and lower-layer properties. A parameterized hetero-CPC model was proposed to describe temperature-by-time curves at the sensing probes in the upper and lower soil layers. The hetero-CPC estimates matched well with the simulated values, and its accuracy relied on the thermal property differences between the soil layers. The heat distributions caused by heat pulse inputs in the layered soils showed semi-circular isotherms with different radii centered on the heating source, therefore showing discrepancies in heat fluxes for the upper and lower soil layers. The proposed hetero-CPC model was able to accurately describe the combined effects of finite probe properties and heterogeneous soil thermal property values on the HP data in a double-layered soil system with the heating probe positioned at the layer interface.

在将热脉冲 (HP) 传感器安装在分层土壤中且加热和传感探头位于不同层的情况下，HP 测量违反了使用的圆柱形完美导体 (CPC) 理论的土壤均匀性的基本假设解释 HP 数据。在这项研究中，进行了实验室和数值研究，以评估传热模式和模型，以分析当加热探头位于具有不同上层和下层特性的双层土壤的界面时的 HP 测量数据。提出了一个参数化的异质 CPC 模型来描述上层和下层土壤中传感探头的温度随时间曲线。异质 CPC 估计值与模拟值非常匹配，其准确性取决于土壤层之间的热特性差异。热脉冲输入在层状土壤中引起的热分布呈半圆形等温线，以热源为中心具有不同的半径，因此上层和下层土壤的热通量存在差异。所提出的异质CPC模型能够准确地描述有限探针特性和异质土壤热特性值对双层土壤系统中HP数据的综合影响，加热探针位于层界面。