Predicting crater formation from failure of pressurized water mains through analogy with buried explosive events

Brittle failure of a buried pressurized water pipe can result in rapid crater formation, causing debris to be thrown out over large distances as well as longer-term flooding and scour effects. Due to the potential for injury and property damage in a failure event, it is desirable to develop policies to enforce safe stand-off distances around high-risk pipes. Little published data are available on the formation of craters during the initial pressure release from a pipe burst, but an analogy can be made with buried explosives events, for which a large body of data exists. This paper uses finite-element modeling of buried pipe failures to assess the parameters affecting crater diameter, where pipe diameter, pressure, air content, and burial depth are shown to be significant. An explosive cratering tool is modified for use with water pipes by converting the energy release from a failing pipe to an equivalent mass of explosive. The modified tool reliably replicates the crater size from the modeling results, and accurately predicts the modeled crater size in new failure scenarios (r2=0.95), indicating the potential of the tool for use in developing policy on safe stand-off distances.