Portable Geotechnical Sensors for Tropical Soils: A Review of Applications, Challenges, and Future Directions in Geoscience

Abstract

Portable geotechnical and soil sensors have emerged as transformative tools for field-based characterization, particularly in contexts where rapid, non-invasive, and scalable measurements are required. This review provides a comprehensive synthesis of recent advances in sensor technologies and their applications to tropical geoscience. Literature published between 2000 and 2025 was systematically screened across major databases, with emphasis on studies relevant to slope stability, hydrology, soil–infrastructure interactions, and biogeochemistry. The results highlight five dominant categories of portable sensors: electrical resistivity probes, TDR/FDR moisture sensors, penetrometers and pressiometers, portable X-ray fluorescence (pXRF), and integrated IoT-enabled devices. These technologies have demonstrated significant potential for monitoring soil strength, infiltration dynamics, contaminant mobility, and the degradation of infrastructure in tropical soils. However, the review also reveals persistent challenges, including calibration drift, site-specific soil variability, environmental constraints, and a gap between laboratory accuracy and field reliability. A geographical imbalance was observed, with most field applications concentrated in Asia and Latin America, and relatively few studies conducted in sub-Saharan Africa. Overall, portable sensors hold strong promise for advancing sustainable geoscience in the tropics, but their broader adoption will require standardized calibration protocols, long-term field validation, and integration into decision-making frameworks.