Assessment of the role of slit as a safety valve in failure of levees

The development of a narrow channel or slit due to piping just underneath the base of levees channel has been reported to be useful to withstand the increase in the head beyond critical head conditions. Also, the maximum slit length has been emphasized to be up to half of the base width. By developing a model of critical head considering slit, it is found that the critical head can increase with the development of slit length only under certain conditions. Analysis of piping failure data indicates that the critical head expressions considering slit length constitute a potentially useful model for critical head.