In areas where the air temperature remains below 0 deg-C for prolonged periods of time,the freezing of water in underground pipes in a major concern. Fortunately, the soil remains relatively warm during those periods, and intakes weeks for the subfreezing temperatures to reach the water mains in the ground. Thus,the soil effectively serves as an insulation to protect the water from freezing atmospheric temperatures in winter. The ground at a particular location is coveredwith snow pack at -8 deg-C for a continuousperiod of 60 days, and the average soilproperties at that location are k = 0.35 W/m*Kand alpha = 0.15 * 10^-6 m^2/s. Assuming theinitial uniform temperature of 8 deg-C for theground, determine the minimum burial depth toprevent the water pipes from freezing.

Fig: 1

Fig: 2