The Influence of the Internal Properties of River Ice on Ground Penetrating Radar Propagation

Abstract

Ground penetrating radar (GPR) has proven to be a very effective method for examining ice thickness. However, two preconditions must be met for this approach to be useful; the round-trip travel time of electromagnetic (EM) waves and radar transmission speed in the ice must be known. These issues are problematic because many factors affect radar transmission speed in ice, including impurities, physical properties such as porosity and density, and temperature. Results show that if these factors are not taken into account and a signal velocity of 0.17 m/ns in pure ice is used to estimate thickness, overestimates will result. We carried out a series of GPR surveys using dual channel host 200 MHz shielded antennas at the Toudaoguai Hydrological Station on the Yellow River, China, and collected samples to analyze ice impurities and physical properties. The results show that the ice crystal types include frazil, granular, and column at the Toudaoguai Hydrologic Station section. Our analysis of ice gas bubble and sediment content showed that the gas bubble volume content is between 11.95 and 13.0% in the frazil ice and between 7.9% and 8.6% in granular and columnar ice. At the same time, the ice sediment content ranged between 0.11‰ and 0.57‰, and the average was 0.24‰ in granular and columnar ice, which was about one-tenth that of the suspended sediment concentration in water. Additionally, a combination of GPR data as well as ice impurities, porosity, density, and temperature enabled us to provide insights on the variability of radar transmission speed and the equivalent dielectric permittivity in river ice. Our extensive observations reveal that radar transmission speed falls between 0.141 m/ns and 0.164 m/ns and that the equivalent dielectric permittivity of river ice increases in concert with ice temperature.

Review of Sensor-Based Subgrade Distress Identifications

“…Ground-penetrating radar (GPR) [22][23][24][25][26] Total station [27][28][29][30][31] InSAR [32][33][34][35][36] Distributed optical fiber [37][38][39][40][41] Subgrade frost heaving Ground-penetrating radar (GPR) [42][43][44][45] Multi-sensor embedding [46][47][48][49][50] Weak subgrade Falling weight deflectometer (FWD) [51][52][53][54][55][56]…”

“…For subgrade frost heaving, Sabbar Abdalsh Salih [27] and others successfully demonstrated the feasibility of detecting low water levels in shallow water by using groundpenetrating radar. Han Hongwei [28] and others successfully used ground-penetrating radar to detect moisture and the existence of ice crystals under the ground depending on the different transmission speeds of electromagnetic waves in different media. Xu Yi [29] and others used ground-penetrating radar to accurately predict the leakage position at the joint of the underground diaphragm wall, used MATLAB to calculate the average wave velocity amplitude and single channel signal of electromagnetic wave velocity of ground-penetrating radar at different mileage, and drew the trend diagram of average wave velocity amplitude with mileage and the corresponding curve of the relationship between electromagnetic wave amplitude and radar depth.…”

Sea, River, Lake Ice Properties and Their Applications in Practices

“…Ground-penetrating radar (GPR) has proven to be a very effective method for examining ice thickness. Han et al (2022) [17] carried out a series of GPR surveys using dual-channel host 200 MHz shielded antennas at the Toudaoguai Hydrological Station on the Yellow River, China, and collected samples to analyze ice impurities and physical properties. A combination of GPR data, as well as ice impurities, porosity, density, and temperature, provides insights into the variability of radar transmission speed and the equivalent dielectric permittivity in river ice.…”