A Combined Methodology of a Finite Element Method and a Sine Cosine Optimization Algorithm for Inversions of the Thermal Conductivity of Soil Around the High-voltage Cable Horizontal Pipe Jacking

Horizontal pipe jacking is an important non-excavation laying way for high-voltage cable lines to cross rivers and streets. The buried depth of horizontal pipe jacking is generally deep, and most of the heat generated in the cable is dissipated through the soil surrounding the pipe. However, the surrounding soil texture and water content distribution are complex for different regions and seasons, resulting in a significant variation in the corresponding soil thermal conductivity. Moreover, it is impossible to directly measure the soil thermal conductivity in engineering applications. In this point of view, a numerical model for numerical calculations of the coupled thermal-fluid field under the horizontal pipe jacking laying of a dual-circuit high-voltage cable is first developed, and the equivalent thermal conductivity is inversed using a standardized improved sine cosine optimization algorithm to obtain the soil thermal conductivity under the practical laying condition, and finally used to calculate the cable current ratting under this laying way. The standardized improvement of the sine cosine algorithm enhances its search ability and its solution speed.