3-Dimensional Stress Analysis and Safety Assessment of the Underground Draft Tube

Abstract

It is well known that research on mechanical characteristics of the underground draft tube and corresponding stress distribution of the steel lining under complex conditions plays an important role on assessing the underground powerhouse and hydropower project safety. However, due to complex boundaries and load conditions of the draft tube, especially the concrete itself is so easy to crack, crush and become plastic that it is more difficult to determine its 3-Dimensional mechanical behavior of the underground draft tube. To better solve the above difficulties, 3-D FEM simulated model was built based on the universal software named Ansys to analyze the stress distribution of the draft tube structure and the steel lining. The calculation results showed that the hoop stress and radial stress of the tube were all satisfied with the standard requirement, and maximum stress of the steel lining also accorded with the strength requirement, which indicated that simulation model and the analysis method brought forward in the paper was applicable and practical, and also provided an effectie method for the underground structures design and steel arrangement of the draft tube.