Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, 205, North Mathews Avenue, Urbana, IL 61801, USA.
School of Civil, Environmental and Architectural Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Korea.
Sensors (Basel). 2019 Sep 5;19(18):3841. doi: 10.3390/s19183841.
Ground moisture content and strength properties are the most important factors for a proper assessment of ground stability. This study developed a dynamic cone penetrometer incorporated with time domain reflectometry (TDR) sensors (TDCP). The TDCP is composed of an anvil, a driving rod, and a TDCP probe. Three wave guides and a K-type thermocouple are installed on the TDCP probe. For utilization of TDCP, relationships between relative permittivities measured by TDCP and those measured by standard TDR probe, temperature, and volumetric water content of the soils were investigated. In addition, the relationship between penetration indices by TDCP (TPI) and by standard dynamic cone penetrometer was established. In the field application test, relative permittivity, ground temperature, and TPI were measured along the depth. Moreover, gravimetric water contents were also measured for comparison. The experimental results showed that volumetric water contents compensated by ground temperature showed good agreement with the volumetric water contents estimated from the gravimetric water contents of the soil samples and TPI. This study suggests that the TDCP may be effectively used for the evaluation moisture contents and for the strength characterization of the subsurface.
土壤湿度含量和强度特性是评估地面稳定性的最重要因素。本研究开发了一种带有时域反射计（TDR）传感器的动锥贯入仪（TDCP）。TDCP 由砧座、驱动杆和 TDCP 探头组成。在 TDCP 探头中安装了三个波导和一个 K 型热电偶。为了利用 TDCP，研究了由 TDCP 测量的相对介电常数与由标准 TDR 探头测量的相对介电常数、温度和土壤体积含水量之间的关系。此外，还建立了 TDCP（TPI）和标准动锥贯入仪的贯入指数之间的关系。在现场应用测试中，沿深度测量相对介电常数、地面温度和 TPI。此外，还测量了重量含水量进行比较。实验结果表明，经地面温度补偿的体积含水量与根据土壤样品的重量含水量和 TPI 估算的体积含水量吻合较好。本研究表明，TDCP 可有效地用于评估地下水位和土壤强度特性。
