Major loss of life can occur after a dam failure when people are toppled by the current of the floodwater. Case histories and available risk analysis procedures are reviewed. Much judgement is involved in the risk analysis. The probability judgements are poorly calibrated because data are scarce. Moreover, risk analysts are hampered without a rational model of the mechanics on which to base their judgements. Three approximate mechanical models and two empirical models of the hydrodynamics of toppling are presented and calibrated to agree with available experimental observations. The mechanical models consider circular cylindrical, square cylindrical and cylindrical composite, heavy bodies assembled to represent a human immersed in a flow field subject to drag and buoyancy forces. The models account for height and weight of those exposed, and velocity and depth of current. the models are in good mutual agreement and, calibrated, yield stability failure functions that can be used to calculate the probability of loss of stability by the methods of structural mechanics.
展开▼
