Unified semi-analytical solution for elastic-plastic stress of deep circular hydraulic tunnel with support yielding

Abstract

A unified semi-analytical solution is presented for elastic-plastic stress of a deep circular hydraulic tunnel with support yielding under plane strain conditions. The rock mass is assumed to be elastic-perfectly plastic and governed by the unified strength theory (UST). Different major principal stresses in different engineering situations and different support yielding conditions are both considered. The unified solution obtained in this work is a series of results, rather than one specific solution, hence it is suitable for a wide range of rock masses. In addition, parametric study is conducted to investigate the effect of intermediate principal stress. The result shows the major principal stress should be rationally chosen according to different engineering conditions. Finally, the applicability of the unified solution is discussed according to the critical pressures.