Figure 12
The horizontal axis, Time in days, uses a logarithmic scale from 10 to the power of minus 2 to 10 to the power of 3. The vertical axis, Normalised mean absolute Shapley additive explanation, ranges from 0.0 to 1.0. Concrete thermal conductivity begins near 0.97, reaches 1.0 before 0.1 days, and then decreases steadily towards 0 by about 300 days. Average soil thermal conductivity begins near 0.05, falls to 0 near 0.1 days, and then rises sharply. It reaches about 1.0 between 20 and 30 days before declining slightly to about 0.93. The curves cross near 1 day at approximately 0.45. Vertical reference lines mark one quarter of t star at 1.60 days, mean t star at 6.4 days and nine quarters of t star at 14.4 days.Normalised mean absolute SHAP importance of concrete and soil thermal conductivities over time, with the mean t*, t*/4 and 9t*/4 overlaid