Deformation of the central pier of the permanent shiplock, Three Gorges Project, China: an analysis case study

摘要

The central pier (CP) is one of the key structures of the permanent shiplock in the Three Gorges Project on the Yangtze River, China. This paper deals with the study of the rock mass deformation of the CP of the second shiplock under various operation conditions. Numerical simulations using the 2-D distinct-element method and 3-D finite-element method are applied to analyze the rock mass deformation. Also, time-series analysis and gray system theory are used to predict the trends of rock displacements based on in situ measured data. The results can be summarized as follows: (1) the main deformation of the rock mass in the CP occurs after excavation completion, while the shiplock is in operation, the dominant displacements mainly occurring on both sides of the northern chamber, developing generally towards the chamber; (2) the horizontal displacement varies with the process of excavation, and is in a steady state after excavation, and during operation of the shiplock the displacement is slightly decreased; (3) the horizontal displacement parallel to the axial line of the shiplock occurs downstream; and (4) the vertical displacement occurs during excavation, and then subsidence with various values takes place in different parts of the CP for different operation conditions.