Nonlinear Stability Performance of Grouted Composite Liner with a Crown Void under a Radially Directed Concentrated Load

This paper is concerned with the nonlinear performance of the grouted liner with a crown void under a concentrated load. The liner consists of three deformed shapes based on three void sizes: the small void, the contact, and the noncontact case, respectively. The theoretical studies are conducted firstly to derive the maximum load (buckling load), which is later verified successfully by the numerical results for all three examined cases. A later developed numerical simulation is implemented to track the load-displacement curves, from which the maximum load is extracted. We found a small crown void shows a negligible reduction on the load capacity (buckling load), compared with the fully grouted liner. This observation suggests the void be constrained that is not larger than the small size level in practical systems. Finally, a full evaluation is taken by analyzing the influence of length and thickness of the void on the buckling load, which indicates the increase of length or thickness of the void reduces the maximum load except for the small void case.