BACK ANALYSIS ON DEFORMATION OF XIAOLANGDI DAM

摘要

Xiaolangdi rockfill dam with an inclined loam core was completed in 2000. The safe operation of the reservoir at high level has passed 7 flood seasons and field measurements of deformation have been obtained during reservoir filling and operation. Through the analysis of displacement based on neural network and evolution calculation method combined with elastic-plastic rheologic model, back analysis was conducted for the prototype measurement of the dam body, and rockfill body strength and rheologic parameters were determined. Two assessment methods, namely, uneven settlement coefficients and horizontal strain, were adopted in the analysis due to the longitudinal crack in the dam crest. The analysis indicates that crack may appear within 6.0m in the vertical direction whether the analysis is based on uneven settlement coefficient or horizontal strain, which is close to the observation results. Prediction was also conducted for the deformation under the conditions of a sudden drawdown in reservoir level, a sudden rise in reservoir level rise and a long-term operation at high level, which reveals no problem about the dam safety under each condition.