Model for detecting multiple concentrated seepage passages in earth dams based on reverse analysis of temperature field

On the basis of the analytic solution of temperature field analysis for detecting a single seepage passage suggested by the authors,a new analytic solution for multiple seepage passages is established by means of superposition principle.The Bursa-Wolf model is used to implement the coordination transformation and the model applying the reverse analysis for detecting multiple concentrated seepage pessages is established.The model is applied to analyze the seepage problem occurred to the earth dam of Douhe Reservoir.The model is simplified as a plane model for temperature detection of multiple cylindrical seepage passages.First,the fitting of the measurement data of single concentrated seepage is carried out,and then the residual errors of every measurement data point relative to the fitting curve can be calculated and used to establish the cubic spline interpolation curve of the errors.The amount of concentrated seepage passages can be directly determined consequently.The analysis result shows that three obvious temperature wave troughs happen to the dam.The three seepage passages located at the left abutment of the dam are accurately determined by optimized calculation method accordingly.This result is in good agreement with the situation of in-situ investigation.