Seepage analysis of a diversion tunnel with high pressure in different periods: a case study

摘要

The seepage field for a diversion tunnel with high pressure in the Coca Codo Sinclair hydroelectric project is investigated using finite difference algorithms during periods of construction completion, operation and overhaul. The transient seepage calculation using FLAC(3D) is verified by a one-dimensional confined flow problem. The equivalent permeability coefficient of the lining, for which cracks are considered, is characterised with empirical formulas. The pressures of the internal and external surfaces of the lining and the external surface of the consolidation grouting region in each period are calculated. The maximum pressure difference between the lining region and the grouted region for each period are obtained. The effect of emptying speed on the seepage field in the emptying period is also discussed.