ABSTRACT
The French National project of research and experimentation named RERAU (Rehabilitation of Urban Network Sewers) has developed a design method for non-circular linings subject to groundwater pressure. The method is based on an analytical approach and gives a formula, recently obtained by O. Thepot, for the buckling pressure of a close-fit non-circular lining subject to external water pressure (with initial annular gap). The method puts the liners into two categories according to their shapes: “critical linings” that are liable to buckle but where the lobe remains localized and “sub-critical linings” that do not buckle but where the lobe may extend to the entire lining. This paper presents the complete analytical method for the critical linings.
