Factors Influencing the Thermal Conductivity of Silt in the Yellow River Delta

The thermal conductivity of marine sediments is an important thermophysical parameter in the study of seafloor heat flow and marine engineering construction. Understanding the effect of thermal conductivity of marine sediments in the environment has a major engineering value and theoretical significance. In this work, a modified test method was used to measure the thermal conductivity of silt in the Yellow River Delta under different void ratios, moisture contents, temperatures, and salinities. Results showed that the thermal conductivity of silt in the Yellow River Delta decreased with the increase in the void ratio and increased with the water content. Compared with sand and clay, silt in the Yellow River Delta was the least affected by the void ratio and moisture content. Under low temperatures, the heat transfer of soil was controlled by the average velocity of the phonons; therefore, the thermal conductivity of silt in the Yellow River Estuary increased with temperature. The thermal conductivity of pore water decreased with increasing salinity. Moreover, certain salinity levels resulted in a phenomenon known as the 'compressing twin electrical layer', which led to an increase in the contact area between soil particles. With the increase in salinity, the thermal conductivity of silt in the Yellow River Delta experiences an initial decline and a subsequent increase. The proposed thermal conductivity test method is more accurate than the existing technique, and the findings provide a basis for further study on the thermal characteristics of submarine sediments.