The ground at a particular location is covered with snow pack at —10°C for a continuous period of 90 days. The average soil properties at that location are: (i) k = 0.4 W/mK, and (ii) a = 0.15 x...

The ground at a particular location is covered with snow pack at —10°C for a continuous period of 90 days. The average soil properties at that location are: (i) k = 0.4 W/mK, and (ii) a = 0.15 x 10-6m2/s. Assuming an initial uniform temperature of 15°C for the ground, determine the maximum depth to bury the water pipes from the surface to avoid freezing.