A single under-reamed pile is installed in a soft clay deposit. The centre of the underream is located at a depth of 15 m from the ground surface. The diameters of the pile shaft and bulb are 1.0 m and 2.5 m respectively. (a) Determine the allowable load with a factor of safety of 2.5. (b)Also determine the allowable load if there is another bulb of the same diameter below the first bulb. The spacing between the centres of the bulbs is 4 m. (Use cu = 65 + 7D, take cu in kN/m2 anda = 1.0.) 5218.97 kN and 7158.9 KN 5466.88 kN and 7789.7 kN 4322.79 kN and 3422.8 kN 5019.43 kN and 7177.3 kN