The buttresses of a free deck buttress dam are provided at ‘x’ m clear spacing and buttress thickness is proposed to be ‘t’ m. The buttress section can then be designed like the section of a concrete gravity dam by considering the effective unit weight of water = Surcharge factor (S) x actual unit weight of water. The value of this surcharge factor is given as _____________

• A. S = (x + t)/x
• B. S = (x + t)/t
• C. S = (x + t)/(x + 1)
• D. S = (x + t)/(t + 1)